Re: [time-nuts] Achieving maximum performance when driving 5370A/B inputs
But YOU don't want to pay for those (OK if someone else is paying) - they are painfully expensive. D. -Original Message- From: time-nuts-boun...@febo.com [mailto:time-nuts-boun...@febo.com] On Behalf Of Bruce Griffiths Sent: 28 February 2010 03:00 To: Discussion of precise time and frequency measurement Subject: Re: [time-nuts] Achieving maximum performance when driving 5370A/B inputs Actually there are miniature twinax style connectors, for example: http://www.amphenolrf.com/products/twinbnc.asp?N=0sid=4B8860805409E17F; http://www.amphenolrf.com/products/twinbnc.asp?N=0sid=4B8860805409E17F; Bruce ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] Achieving maximum performance when driving 5370A/B inputs
Hi That's been my experience in the past with unusual RF connectors. Unless they went into large scale production you can't afford them. Bob On Mar 1, 2010, at 7:44 AM, David C. Partridge wrote: But YOU don't want to pay for those (OK if someone else is paying) - they are painfully expensive. D. -Original Message- From: time-nuts-boun...@febo.com [mailto:time-nuts-boun...@febo.com] On Behalf Of Bruce Griffiths Sent: 28 February 2010 03:00 To: Discussion of precise time and frequency measurement Subject: Re: [time-nuts] Achieving maximum performance when driving 5370A/B inputs Actually there are miniature twinax style connectors, for example: http://www.amphenolrf.com/products/twinbnc.asp?N=0sid=4B8860805409E17F; http://www.amphenolrf.com/products/twinbnc.asp?N=0sid=4B8860805409E17F; Bruce ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] Achieving maximum performance when driving 5370A/B inputs
The 0032 was an op-amp and the 0033 and 0063 a buffer. The 0063 was a high power/higher slew-rate version. They were, and still are, great to use. I do have some 0032s and 0033s. Never played with the 0063. 73 - Mike Mike B. Feher, N4FS 89 Arnold Blvd. Howell, NJ, 07731 732-886-5960 -Original Message- From: time-nuts-boun...@febo.com [mailto:time-nuts-boun...@febo.com] On Behalf Of Bruce Griffiths Sent: Saturday, February 27, 2010 9:56 PM To: Discussion of precise time and frequency measurement Subject: Re: [time-nuts] Achieving maximum performance when driving 5370A/B inputs Mike Feher wrote: In general, what about the old National damn fast and super damn fast LH0032 LH0033? I used to use a lot of those in my designs many years ago. - Mike Mike B. Feher, N4FS 89 Arnold Blvd. Howell, NJ, 07731 732-886-5960 The LH0032 was a fast FET input opamp. I presume you meant the LH0033 and LH0063? Their slew rate is adequate to ensure that the 5370A/B trigger jitter is insignificant. However they need a negative supply as well as the positive supply when being driven by a 3.3V or 5V CMOS output. Bruce ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] Achieving maximum performance when driving 5370A/B inputs
Hi That's the one, right down to the description of the pots. If it doesn't become a working counter, it's cheap enough to be a parts donor. Of course having multiple counters all with the exact same broken parts doesn't do much good . For the external arm level control I might go for a fixed level and forget about the pot entirely. It's been about 20 years since I've played with a 5370, so Im drawing a blank on the display update control. Bob On Feb 28, 2010, at 12:10 AM, Mark Sims wrote: If it's the one that I think it is... look closely at the photo. The shafts on two of the pots are sheared off at the panel. These are the display update control and the external arming level control. These were custom HP pots with a funky (and delicate) switch. They had brittle plastic shafts. Gee, how do I know this... could it be that a large percentage of the 5370's for sale have the same defect? Luckily those controls are not too critical for normal operation. They can be replaced with regular (switchless) pots if you jumper the switch pads correctly. Be careful, there were two different layouts to those controls. -- So exactly how did you know that I bought a (cheap) 5370B a few hours ago on the e-place _ Hotmail: Trusted email with powerful SPAM protection. http://clk.atdmt.com/GBL/go/201469227/direct/01/ ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] Achieving maximum performance when driving 5370A/B inputs
Today I have been trying to drive a 5370B directly from a TADD-2, with little luck (other HP freq counters seem to work OK). I was about to ask about it on this list, but noticed this thread. I guess this could explain why I am getting erroneous, random readings? Dave On Sat, Feb 27, 2010 at 4:01 PM, Bruce Griffiths bruce.griffi...@xtra.co.nz wrote: The attached excerpts from the 5370A and 5370B manuals indicate that for best performance, that the common practice of driving the 5370A/B 1x inputs directly from a 5V CMOS logic signal is a bad idea. For the 5370A attenuating the 5V CMOS signal to a 1V swing with the threshold set to 0.5V is close to optimum. An input signal with limits of 0V and +1.4V with a trigger threshold of 0.7V is the maximum usable (for high performance). An input signal with limits of 0V and +0.3V with a trigger threshold of 0.15V is the minimum usable (for high performance). For the 5370A attenuating the 5V CMOS signal to a 2V swing with the threshold set to 1V is close to optimum. An input signal with limits of 0V and +3.5V with a trigger threshold of 0.7V is the maximum usable (for high performance). An input signal with limits of 0V and +0.3V with a trigger threshold of 0.15V is the minimum usable (for high performance). Bruce ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] Achieving maximum performance when driving 5370A/B inputs
The TADD-2 output drivers exhibit significant ringing and crosstalk due to ground and Vcc bounce. To minimise crosstalk dedicate each 74AC04 output device to a single frequency and load. Because of the ringing setting the trigger threshold is more critical than usual. No damage occurs when driving the 5370A/B 1x inputs with 5V logic levels however various protection diodes will turn on and the preamp input stage becomes nonlinear. Bruce Dave hartzell wrote: Today I have been trying to drive a 5370B directly from a TADD-2, with little luck (other HP freq counters seem to work OK). I was about to ask about it on this list, but noticed this thread. I guess this could explain why I am getting erroneous, random readings? Dave On Sat, Feb 27, 2010 at 4:01 PM, Bruce Griffithsbruce.griffi...@xtra.co.nz wrote: The attached excerpts from the 5370A and 5370B manuals indicate that for best performance, that the common practice of driving the 5370A/B 1x inputs directly from a 5V CMOS logic signal is a bad idea. For the 5370A attenuating the 5V CMOS signal to a 1V swing with the threshold set to 0.5V is close to optimum. An input signal with limits of 0V and +1.4V with a trigger threshold of 0.7V is the maximum usable (for high performance). An input signal with limits of 0V and +0.3V with a trigger threshold of 0.15V is the minimum usable (for high performance). For the 5370A attenuating the 5V CMOS signal to a 2V swing with the threshold set to 1V is close to optimum. An input signal with limits of 0V and +3.5V with a trigger threshold of 0.7V is the maximum usable (for high performance). An input signal with limits of 0V and +0.3V with a trigger threshold of 0.15V is the minimum usable (for high performance). Bruce ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] Achieving maximum performance when driving 5370A/B inputs
Thanks for the tips Bruce. Is there a better version of the 74AC04? It sounds like I should also use an attenuator, perhaps 3 - 10 dB... Dave On Sun, Feb 28, 2010 at 7:43 PM, Bruce Griffiths bruce.griffi...@xtra.co.nz wrote: The TADD-2 output drivers exhibit significant ringing and crosstalk due to ground and Vcc bounce. To minimise crosstalk dedicate each 74AC04 output device to a single frequency and load. Because of the ringing setting the trigger threshold is more critical than usual. No damage occurs when driving the 5370A/B 1x inputs with 5V logic levels however various protection diodes will turn on and the preamp input stage becomes nonlinear. Bruce ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] Achieving maximum performance when driving 5370A/B inputs
You could substitute a 74AHC04 which has better control of ground and Vcc bounce. At least they are specified. At least a 3dB attenuator with a 5370B. at least 11dB with a 5370A. Or just use the built in 20dB (10x) attenuator. Bruce Dave hartzell wrote: Thanks for the tips Bruce. Is there a better version of the 74AC04? It sounds like I should also use an attenuator, perhaps 3 - 10 dB... Dave On Sun, Feb 28, 2010 at 7:43 PM, Bruce Griffithsbruce.griffi...@xtra.co.nz wrote: The TADD-2 output drivers exhibit significant ringing and crosstalk due to ground and Vcc bounce. To minimise crosstalk dedicate each 74AC04 output device to a single frequency and load. Because of the ringing setting the trigger threshold is more critical than usual. No damage occurs when driving the 5370A/B 1x inputs with 5V logic levels however various protection diodes will turn on and the preamp input stage becomes nonlinear. Bruce ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] Achieving maximum performance when driving 5370A/B inputs
At 07:01 PM 2/27/2010, Bruce Griffiths wrote... For the 5370A attenuating the 5V CMOS signal to a 1V... For the 5370A attenuating the 5V CMOS signal to a 2V... ITYM 5370B for the second part. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] Achieving maximum performance when driving 5370A/B inputs
Oops! a small correction (2nd paragraph): For the 5370A attenuating the 5V CMOS signal to a 1V swing with the threshold set to 0.5V is close to optimum. An input signal with limits of 0V and +1.4V with a trigger threshold of 0.7V is the maximum usable (for high performance). An input signal with limits of 0V and +0.3V with a trigger threshold of 0.15V is the minimum usable (for high performance). For the 5370B attenuating the 5V CMOS signal to a 2V swing with the threshold set to 1V is close to optimum. An input signal with limits of 0V and +3.5V with a trigger threshold of 0.7V is the maximum usable (for high performance). An input signal with limits of 0V and +0.3V with a trigger threshold of 0.15V is the minimum usable (for high performance). Thus using the PPS output (~270 ohm is series with a 5V 74AC04 output) from a Synergy evaluation board that uses an M12M or M12+ GPS timing receiver to drive the inputs (with a 0-750mV signal) of a 5370A or 5370B is well within the recommended input signal range for high performance. This avoids having to adding an external 5V 50 ohm driver that some would use. Bruce Bob Camp wrote: Hi So exactly how did you know that I bought a (cheap) 5370B a few hours ago on the e-place and was just about to ask about how best to use it. H... Bob On Feb 27, 2010, at 7:01 PM, Bruce Griffiths wrote: The attached excerpts from the 5370A and 5370B manuals indicate that for best performance, that the common practice of driving the 5370A/B 1x inputs directly from a 5V CMOS logic signal is a bad idea. For the 5370A attenuating the 5V CMOS signal to a 1V swing with the threshold set to 0.5V is close to optimum. An input signal with limits of 0V and +1.4V with a trigger threshold of 0.7V is the maximum usable (for high performance). An input signal with limits of 0V and +0.3V with a trigger threshold of 0.15V is the minimum usable (for high performance). For the 5370A attenuating the 5V CMOS signal to a 2V swing with the threshold set to 1V is close to optimum. An input signal with limits of 0V and +3.5V with a trigger threshold of 0.7V is the maximum usable (for high performance). An input signal with limits of 0V and +0.3V with a trigger threshold of 0.15V is the minimum usable (for high performance). Bruce 5370ATriggering.png5370BTriggering.png___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] Achieving maximum performance when driving 5370A/B inputs
Hi Which *still* carefully avoids the issue of how . Bob On Feb 27, 2010, at 8:52 PM, Bruce Griffiths wrote: Oops! a small correction (2nd paragraph): For the 5370A attenuating the 5V CMOS signal to a 1V swing with the threshold set to 0.5V is close to optimum. An input signal with limits of 0V and +1.4V with a trigger threshold of 0.7V is the maximum usable (for high performance). An input signal with limits of 0V and +0.3V with a trigger threshold of 0.15V is the minimum usable (for high performance). For the 5370B attenuating the 5V CMOS signal to a 2V swing with the threshold set to 1V is close to optimum. An input signal with limits of 0V and +3.5V with a trigger threshold of 0.7V is the maximum usable (for high performance). An input signal with limits of 0V and +0.3V with a trigger threshold of 0.15V is the minimum usable (for high performance). Thus using the PPS output (~270 ohm is series with a 5V 74AC04 output) from a Synergy evaluation board that uses an M12M or M12+ GPS timing receiver to drive the inputs (with a 0-750mV signal) of a 5370A or 5370B is well within the recommended input signal range for high performance. This avoids having to adding an external 5V 50 ohm driver that some would use. Bruce Bob Camp wrote: Hi So exactly how did you know that I bought a (cheap) 5370B a few hours ago on the e-place and was just about to ask about how best to use it. H... Bob On Feb 27, 2010, at 7:01 PM, Bruce Griffiths wrote: The attached excerpts from the 5370A and 5370B manuals indicate that for best performance, that the common practice of driving the 5370A/B 1x inputs directly from a 5V CMOS logic signal is a bad idea. For the 5370A attenuating the 5V CMOS signal to a 1V swing with the threshold set to 0.5V is close to optimum. An input signal with limits of 0V and +1.4V with a trigger threshold of 0.7V is the maximum usable (for high performance). An input signal with limits of 0V and +0.3V with a trigger threshold of 0.15V is the minimum usable (for high performance). For the 5370A attenuating the 5V CMOS signal to a 2V swing with the threshold set to 1V is close to optimum. An input signal with limits of 0V and +3.5V with a trigger threshold of 0.7V is the maximum usable (for high performance). An input signal with limits of 0V and +0.3V with a trigger threshold of 0.15V is the minimum usable (for high performance). Bruce 5370ATriggering.png5370BTriggering.png___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] Achieving maximum performance when driving 5370A/B inputs
Mike S wrote: At 07:01 PM 2/27/2010, Bruce Griffiths wrote... For the 5370A attenuating the 5V CMOS signal to a 1V... For the 5370A attenuating the 5V CMOS signal to a 2V... ITYM 5370B for the second part. Yes, a result of cutting and pasting. Bruce ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] Achieving maximum performance when driving 5370A/B inputs
1) One method with 5V CMOS is to add a resistive voltage divider at the CMOS driver output with a 50 ohm output impedance at the tap that drives the 5370A/B input. 2) If one has a 5V 50 ohm driver (eg Thunderbolt PPS output) use a 50 ohm attenuator at the 5370A/B input. For a 5370A an attenuation of at least 11dB is required. For a 5370B an attenuation of at least 3dB is required. 3) One can always use the 10x input attenuation setting built in to the 5370A/B however this reduces the signal swing to 0.5V at the trigger amplifier input (5V CMOS input). 4) Attenuate the output of the logic signal by a factor of 2 and use an npn emitter follower to drive the 50 ohm load. 5) Use 3.3V CMOS signal levels for the 5370B. 6) Use a current mode emitter or source coupled switch to drive the 5370A/B input. The switching jitter of the above drivers will be much lower than the internal noise of the 5370A/B as long as HCMOS or faster logic is employed. Bruce Bob Camp wrote: Hi Which *still* carefully avoids the issue of how . Bob On Feb 27, 2010, at 8:52 PM, Bruce Griffiths wrote: Oops! a small correction (2nd paragraph): For the 5370A attenuating the 5V CMOS signal to a 1V swing with the threshold set to 0.5V is close to optimum. An input signal with limits of 0V and +1.4V with a trigger threshold of 0.7V is the maximum usable (for high performance). An input signal with limits of 0V and +0.3V with a trigger threshold of 0.15V is the minimum usable (for high performance). For the 5370B attenuating the 5V CMOS signal to a 2V swing with the threshold set to 1V is close to optimum. An input signal with limits of 0V and +3.5V with a trigger threshold of 0.7V is the maximum usable (for high performance). An input signal with limits of 0V and +0.3V with a trigger threshold of 0.15V is the minimum usable (for high performance). Thus using the PPS output (~270 ohm is series with a 5V 74AC04 output) from a Synergy evaluation board that uses an M12M or M12+ GPS timing receiver to drive the inputs (with a 0-750mV signal) of a 5370A or 5370B is well within the recommended input signal range for high performance. This avoids having to adding an external 5V 50 ohm driver that some would use. Bruce Bob Camp wrote: Hi So exactly how did you know that I bought a (cheap) 5370B a few hours ago on the e-place and was just about to ask about how best to use it. H... Bob On Feb 27, 2010, at 7:01 PM, Bruce Griffiths wrote: The attached excerpts from the 5370A and 5370B manuals indicate that for best performance, that the common practice of driving the 5370A/B 1x inputs directly from a 5V CMOS logic signal is a bad idea. For the 5370A attenuating the 5V CMOS signal to a 1V swing with the threshold set to 0.5V is close to optimum. An input signal with limits of 0V and +1.4V with a trigger threshold of 0.7V is the maximum usable (for high performance). An input signal with limits of 0V and +0.3V with a trigger threshold of 0.15V is the minimum usable (for high performance). For the 5370A attenuating the 5V CMOS signal to a 2V swing with the threshold set to 1V is close to optimum. An input signal with limits of 0V and +3.5V with a trigger threshold of 0.7V is the maximum usable (for high performance). An input signal with limits of 0V and +0.3V with a trigger threshold of 0.15V is the minimum usable (for high performance). Bruce 5370ATriggering.png5370BTriggering.png___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] Achieving maximum performance when driving 5370A/B inputs
Hi AC cmos will easily drive an L pad to match a 50 ohm cable at these levels. That's true at either 3.3 or at 5.0 volts. There are a lot of cmos families out there that beat AC for speed and match the output drive capability. Bob On Feb 27, 2010, at 9:12 PM, Bruce Griffiths wrote: 1) One method with 5V CMOS is to add a resistive voltage divider at the CMOS driver output with a 50 ohm output impedance at the tap that drives the 5370A/B input. 2) If one has a 5V 50 ohm driver (eg Thunderbolt PPS output) use a 50 ohm attenuator at the 5370A/B input. For a 5370A an attenuation of at least 11dB is required. For a 5370B an attenuation of at least 3dB is required. 3) One can always use the 10x input attenuation setting built in to the 5370A/B however this reduces the signal swing to 0.5V at the trigger amplifier input (5V CMOS input). 4) Attenuate the output of the logic signal by a factor of 2 and use an npn emitter follower to drive the 50 ohm load. 5) Use 3.3V CMOS signal levels for the 5370B. 6) Use a current mode emitter or source coupled switch to drive the 5370A/B input. The switching jitter of the above drivers will be much lower than the internal noise of the 5370A/B as long as HCMOS or faster logic is employed. Bruce Bob Camp wrote: Hi Which *still* carefully avoids the issue of how . Bob On Feb 27, 2010, at 8:52 PM, Bruce Griffiths wrote: Oops! a small correction (2nd paragraph): For the 5370A attenuating the 5V CMOS signal to a 1V swing with the threshold set to 0.5V is close to optimum. An input signal with limits of 0V and +1.4V with a trigger threshold of 0.7V is the maximum usable (for high performance). An input signal with limits of 0V and +0.3V with a trigger threshold of 0.15V is the minimum usable (for high performance). For the 5370B attenuating the 5V CMOS signal to a 2V swing with the threshold set to 1V is close to optimum. An input signal with limits of 0V and +3.5V with a trigger threshold of 0.7V is the maximum usable (for high performance). An input signal with limits of 0V and +0.3V with a trigger threshold of 0.15V is the minimum usable (for high performance). Thus using the PPS output (~270 ohm is series with a 5V 74AC04 output) from a Synergy evaluation board that uses an M12M or M12+ GPS timing receiver to drive the inputs (with a 0-750mV signal) of a 5370A or 5370B is well within the recommended input signal range for high performance. This avoids having to adding an external 5V 50 ohm driver that some would use. Bruce Bob Camp wrote: Hi So exactly how did you know that I bought a (cheap) 5370B a few hours ago on the e-place and was just about to ask about how best to use it. H... Bob On Feb 27, 2010, at 7:01 PM, Bruce Griffiths wrote: The attached excerpts from the 5370A and 5370B manuals indicate that for best performance, that the common practice of driving the 5370A/B 1x inputs directly from a 5V CMOS logic signal is a bad idea. For the 5370A attenuating the 5V CMOS signal to a 1V swing with the threshold set to 0.5V is close to optimum. An input signal with limits of 0V and +1.4V with a trigger threshold of 0.7V is the maximum usable (for high performance). An input signal with limits of 0V and +0.3V with a trigger threshold of 0.15V is the minimum usable (for high performance). For the 5370A attenuating the 5V CMOS signal to a 2V swing with the threshold set to 1V is close to optimum. An input signal with limits of 0V and +3.5V with a trigger threshold of 0.7V is the maximum usable (for high performance). An input signal with limits of 0V and +0.3V with a trigger threshold of 0.15V is the minimum usable (for high performance). Bruce 5370ATriggering.png5370BTriggering.png___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] Achieving maximum performance when driving 5370A/B inputs
If one is feeling paranoid about ground loop noise (and wishes to avoid transformers, optoisolators , or fibre optics), etc one could always use an LVDS driver with a batter powered(?) LVDS to CMOS receiver/translator right at the 5370A/B input BNC connector. This may be useful for a DMTD system that uses a 5370A/B. Bruce Bob Camp wrote: Hi AC cmos will easily drive an L pad to match a 50 ohm cable at these levels. That's true at either 3.3 or at 5.0 volts. There are a lot of cmos families out there that beat AC for speed and match the output drive capability. Bob On Feb 27, 2010, at 9:12 PM, Bruce Griffiths wrote: 1) One method with 5V CMOS is to add a resistive voltage divider at the CMOS driver output with a 50 ohm output impedance at the tap that drives the 5370A/B input. 2) If one has a 5V 50 ohm driver (eg Thunderbolt PPS output) use a 50 ohm attenuator at the 5370A/B input. For a 5370A an attenuation of at least 11dB is required. For a 5370B an attenuation of at least 3dB is required. 3) One can always use the 10x input attenuation setting built in to the 5370A/B however this reduces the signal swing to 0.5V at the trigger amplifier input (5V CMOS input). 4) Attenuate the output of the logic signal by a factor of 2 and use an npn emitter follower to drive the 50 ohm load. 5) Use 3.3V CMOS signal levels for the 5370B. 6) Use a current mode emitter or source coupled switch to drive the 5370A/B input. The switching jitter of the above drivers will be much lower than the internal noise of the 5370A/B as long as HCMOS or faster logic is employed. Bruce Bob Camp wrote: Hi Which *still* carefully avoids the issue of how . Bob On Feb 27, 2010, at 8:52 PM, Bruce Griffiths wrote: Oops! a small correction (2nd paragraph): For the 5370A attenuating the 5V CMOS signal to a 1V swing with the threshold set to 0.5V is close to optimum. An input signal with limits of 0V and +1.4V with a trigger threshold of 0.7V is the maximum usable (for high performance). An input signal with limits of 0V and +0.3V with a trigger threshold of 0.15V is the minimum usable (for high performance). For the 5370B attenuating the 5V CMOS signal to a 2V swing with the threshold set to 1V is close to optimum. An input signal with limits of 0V and +3.5V with a trigger threshold of 0.7V is the maximum usable (for high performance). An input signal with limits of 0V and +0.3V with a trigger threshold of 0.15V is the minimum usable (for high performance). Thus using the PPS output (~270 ohm is series with a 5V 74AC04 output) from a Synergy evaluation board that uses an M12M or M12+ GPS timing receiver to drive the inputs (with a 0-750mV signal) of a 5370A or 5370B is well within the recommended input signal range for high performance. This avoids having to adding an external 5V 50 ohm driver that some would use. Bruce Bob Camp wrote: Hi So exactly how did you know that I bought a (cheap) 5370B a few hours ago on the e-place and was just about to ask about how best to use it. H... Bob On Feb 27, 2010, at 7:01 PM, Bruce Griffiths wrote: The attached excerpts from the 5370A and 5370B manuals indicate that for best performance, that the common practice of driving the 5370A/B 1x inputs directly from a 5V CMOS logic signal is a bad idea. For the 5370A attenuating the 5V CMOS signal to a 1V swing with the threshold set to 0.5V is close to optimum. An input signal with limits of 0V and +1.4V with a trigger threshold of 0.7V is the maximum usable (for high performance). An input signal with limits of 0V and +0.3V with a trigger threshold of 0.15V is the minimum usable (for high performance). For the 5370A attenuating the 5V CMOS signal to a 2V swing with the threshold set to 1V is close to optimum. An input signal with limits of 0V and +3.5V with a trigger threshold of 0.7V is the maximum usable (for high performance). An input signal with limits of 0V and +0.3V with a trigger threshold of 0.15V is the minimum usable (for high performance). Bruce 5370ATriggering.png5370BTriggering.png___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the
Re: [time-nuts] Achieving maximum performance when driving 5370A/B inputs
Hi Gee, LVDS what an unusual approach :) It would be nice if these instruments had a balanced input. Common mode noise is indeed an issue in a lot of cases. Of course wrapping the coax headed to the counter 10X around a fairly large core can help things a bit. Bob On Feb 27, 2010, at 9:32 PM, Bruce Griffiths wrote: If one is feeling paranoid about ground loop noise (and wishes to avoid transformers, optoisolators , or fibre optics), etc one could always use an LVDS driver with a batter powered(?) LVDS to CMOS receiver/translator right at the 5370A/B input BNC connector. This may be useful for a DMTD system that uses a 5370A/B. Bruce Bob Camp wrote: Hi AC cmos will easily drive an L pad to match a 50 ohm cable at these levels. That's true at either 3.3 or at 5.0 volts. There are a lot of cmos families out there that beat AC for speed and match the output drive capability. Bob On Feb 27, 2010, at 9:12 PM, Bruce Griffiths wrote: 1) One method with 5V CMOS is to add a resistive voltage divider at the CMOS driver output with a 50 ohm output impedance at the tap that drives the 5370A/B input. 2) If one has a 5V 50 ohm driver (eg Thunderbolt PPS output) use a 50 ohm attenuator at the 5370A/B input. For a 5370A an attenuation of at least 11dB is required. For a 5370B an attenuation of at least 3dB is required. 3) One can always use the 10x input attenuation setting built in to the 5370A/B however this reduces the signal swing to 0.5V at the trigger amplifier input (5V CMOS input). 4) Attenuate the output of the logic signal by a factor of 2 and use an npn emitter follower to drive the 50 ohm load. 5) Use 3.3V CMOS signal levels for the 5370B. 6) Use a current mode emitter or source coupled switch to drive the 5370A/B input. The switching jitter of the above drivers will be much lower than the internal noise of the 5370A/B as long as HCMOS or faster logic is employed. Bruce Bob Camp wrote: Hi Which *still* carefully avoids the issue of how . Bob On Feb 27, 2010, at 8:52 PM, Bruce Griffiths wrote: Oops! a small correction (2nd paragraph): For the 5370A attenuating the 5V CMOS signal to a 1V swing with the threshold set to 0.5V is close to optimum. An input signal with limits of 0V and +1.4V with a trigger threshold of 0.7V is the maximum usable (for high performance). An input signal with limits of 0V and +0.3V with a trigger threshold of 0.15V is the minimum usable (for high performance). For the 5370B attenuating the 5V CMOS signal to a 2V swing with the threshold set to 1V is close to optimum. An input signal with limits of 0V and +3.5V with a trigger threshold of 0.7V is the maximum usable (for high performance). An input signal with limits of 0V and +0.3V with a trigger threshold of 0.15V is the minimum usable (for high performance). Thus using the PPS output (~270 ohm is series with a 5V 74AC04 output) from a Synergy evaluation board that uses an M12M or M12+ GPS timing receiver to drive the inputs (with a 0-750mV signal) of a 5370A or 5370B is well within the recommended input signal range for high performance. This avoids having to adding an external 5V 50 ohm driver that some would use. Bruce Bob Camp wrote: Hi So exactly how did you know that I bought a (cheap) 5370B a few hours ago on the e-place and was just about to ask about how best to use it. H... Bob On Feb 27, 2010, at 7:01 PM, Bruce Griffiths wrote: The attached excerpts from the 5370A and 5370B manuals indicate that for best performance, that the common practice of driving the 5370A/B 1x inputs directly from a 5V CMOS logic signal is a bad idea. For the 5370A attenuating the 5V CMOS signal to a 1V swing with the threshold set to 0.5V is close to optimum. An input signal with limits of 0V and +1.4V with a trigger threshold of 0.7V is the maximum usable (for high performance). An input signal with limits of 0V and +0.3V with a trigger threshold of 0.15V is the minimum usable (for high performance). For the 5370A attenuating the 5V CMOS signal to a 2V swing with the threshold set to 1V is close to optimum. An input signal with limits of 0V and +3.5V with a trigger threshold of 0.7V is the maximum usable (for high performance). An input signal with limits of 0V and +0.3V with a trigger threshold of 0.15V is the minimum usable (for high performance). Bruce 5370ATriggering.png5370BTriggering.png___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and
Re: [time-nuts] Achieving maximum performance when driving 5370A/B inputs
In general, what about the old National damn fast and super damn fast LH0032 LH0033? I used to use a lot of those in my designs many years ago. - Mike Mike B. Feher, N4FS 89 Arnold Blvd. Howell, NJ, 07731 732-886-5960 ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] Achieving maximum performance when driving 5370A/B inputs
Since the input amplifier and trigger circuit are located on a small daughter board it wouldn't be too difficult to replace this with an LVDS to CML stage. The only remaining isue would be what input connector to use (twinax??, SATA??). Bruce Bob Camp wrote: Hi Gee, LVDS what an unusual approach :) It would be nice if these instruments had a balanced input. Common mode noise is indeed an issue in a lot of cases. Of course wrapping the coax headed to the counter 10X around a fairly large core can help things a bit. Bob On Feb 27, 2010, at 9:32 PM, Bruce Griffiths wrote: If one is feeling paranoid about ground loop noise (and wishes to avoid transformers, optoisolators , or fibre optics), etc one could always use an LVDS driver with a batter powered(?) LVDS to CMOS receiver/translator right at the 5370A/B input BNC connector. This may be useful for a DMTD system that uses a 5370A/B. Bruce Bob Camp wrote: Hi AC cmos will easily drive an L pad to match a 50 ohm cable at these levels. That's true at either 3.3 or at 5.0 volts. There are a lot of cmos families out there that beat AC for speed and match the output drive capability. Bob On Feb 27, 2010, at 9:12 PM, Bruce Griffiths wrote: 1) One method with 5V CMOS is to add a resistive voltage divider at the CMOS driver output with a 50 ohm output impedance at the tap that drives the 5370A/B input. 2) If one has a 5V 50 ohm driver (eg Thunderbolt PPS output) use a 50 ohm attenuator at the 5370A/B input. For a 5370A an attenuation of at least 11dB is required. For a 5370B an attenuation of at least 3dB is required. 3) One can always use the 10x input attenuation setting built in to the 5370A/B however this reduces the signal swing to 0.5V at the trigger amplifier input (5V CMOS input). 4) Attenuate the output of the logic signal by a factor of 2 and use an npn emitter follower to drive the 50 ohm load. 5) Use 3.3V CMOS signal levels for the 5370B. 6) Use a current mode emitter or source coupled switch to drive the 5370A/B input. The switching jitter of the above drivers will be much lower than the internal noise of the 5370A/B as long as HCMOS or faster logic is employed. Bruce Bob Camp wrote: Hi Which *still* carefully avoids the issue of how . Bob On Feb 27, 2010, at 8:52 PM, Bruce Griffiths wrote: Oops! a small correction (2nd paragraph): For the 5370A attenuating the 5V CMOS signal to a 1V swing with the threshold set to 0.5V is close to optimum. An input signal with limits of 0V and +1.4V with a trigger threshold of 0.7V is the maximum usable (for high performance). An input signal with limits of 0V and +0.3V with a trigger threshold of 0.15V is the minimum usable (for high performance). For the 5370B attenuating the 5V CMOS signal to a 2V swing with the threshold set to 1V is close to optimum. An input signal with limits of 0V and +3.5V with a trigger threshold of 0.7V is the maximum usable (for high performance). An input signal with limits of 0V and +0.3V with a trigger threshold of 0.15V is the minimum usable (for high performance). Thus using the PPS output (~270 ohm is series with a 5V 74AC04 output) from a Synergy evaluation board that uses an M12M or M12+ GPS timing receiver to drive the inputs (with a 0-750mV signal) of a 5370A or 5370B is well within the recommended input signal range for high performance. This avoids having to adding an external 5V 50 ohm driver that some would use. Bruce Bob Camp wrote: Hi So exactly how did you know that I bought a (cheap) 5370B a few hours ago on the e-place and was just about to ask about how best to use it. H... Bob On Feb 27, 2010, at 7:01 PM, Bruce Griffiths wrote: The attached excerpts from the 5370A and 5370B manuals indicate that for best performance, that the common practice of driving the 5370A/B 1x inputs directly from a 5V CMOS logic signal is a bad idea. For the 5370A attenuating the 5V CMOS signal to a 1V swing with the threshold set to 0.5V is close to optimum. An input signal with limits of 0V and +1.4V with a trigger threshold of 0.7V is the maximum usable (for high performance). An input signal with limits of 0V and +0.3V with a trigger threshold of 0.15V is the minimum usable (for high performance). For the 5370A attenuating the 5V CMOS signal to a 2V swing with the threshold set to 1V is close to optimum. An input signal with limits of 0V and +3.5V with a trigger threshold of 0.7V is the maximum usable (for high performance). An input signal with limits of 0V and +0.3V with a trigger threshold of 0.15V is the minimum usable (for high performance). Bruce 5370ATriggering.png5370BTriggering.png___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] Achieving maximum performance when driving 5370A/B inputs
Hi I don't even have the counter and already we're butchering it The big issue is suitable twin-ax connectors and cable. I have both, but they are *big*. They never really made it into the world of miniature connectors and miniature cable. Shielded twisted pair would be another option. That eliminates the cable as an issue. Small connectors (BNC drop in) are still an issue though. Bob On Feb 27, 2010, at 9:48 PM, Bruce Griffiths wrote: Since the input amplifier and trigger circuit are located on a small daughter board it wouldn't be too difficult to replace this with an LVDS to CML stage. The only remaining isue would be what input connector to use (twinax??, SATA??). Bruce Bob Camp wrote: Hi Gee, LVDS what an unusual approach :) It would be nice if these instruments had a balanced input. Common mode noise is indeed an issue in a lot of cases. Of course wrapping the coax headed to the counter 10X around a fairly large core can help things a bit. Bob On Feb 27, 2010, at 9:32 PM, Bruce Griffiths wrote: If one is feeling paranoid about ground loop noise (and wishes to avoid transformers, optoisolators , or fibre optics), etc one could always use an LVDS driver with a batter powered(?) LVDS to CMOS receiver/translator right at the 5370A/B input BNC connector. This may be useful for a DMTD system that uses a 5370A/B. Bruce Bob Camp wrote: Hi AC cmos will easily drive an L pad to match a 50 ohm cable at these levels. That's true at either 3.3 or at 5.0 volts. There are a lot of cmos families out there that beat AC for speed and match the output drive capability. Bob On Feb 27, 2010, at 9:12 PM, Bruce Griffiths wrote: 1) One method with 5V CMOS is to add a resistive voltage divider at the CMOS driver output with a 50 ohm output impedance at the tap that drives the 5370A/B input. 2) If one has a 5V 50 ohm driver (eg Thunderbolt PPS output) use a 50 ohm attenuator at the 5370A/B input. For a 5370A an attenuation of at least 11dB is required. For a 5370B an attenuation of at least 3dB is required. 3) One can always use the 10x input attenuation setting built in to the 5370A/B however this reduces the signal swing to 0.5V at the trigger amplifier input (5V CMOS input). 4) Attenuate the output of the logic signal by a factor of 2 and use an npn emitter follower to drive the 50 ohm load. 5) Use 3.3V CMOS signal levels for the 5370B. 6) Use a current mode emitter or source coupled switch to drive the 5370A/B input. The switching jitter of the above drivers will be much lower than the internal noise of the 5370A/B as long as HCMOS or faster logic is employed. Bruce Bob Camp wrote: Hi Which *still* carefully avoids the issue of how . Bob On Feb 27, 2010, at 8:52 PM, Bruce Griffiths wrote: Oops! a small correction (2nd paragraph): For the 5370A attenuating the 5V CMOS signal to a 1V swing with the threshold set to 0.5V is close to optimum. An input signal with limits of 0V and +1.4V with a trigger threshold of 0.7V is the maximum usable (for high performance). An input signal with limits of 0V and +0.3V with a trigger threshold of 0.15V is the minimum usable (for high performance). For the 5370B attenuating the 5V CMOS signal to a 2V swing with the threshold set to 1V is close to optimum. An input signal with limits of 0V and +3.5V with a trigger threshold of 0.7V is the maximum usable (for high performance). An input signal with limits of 0V and +0.3V with a trigger threshold of 0.15V is the minimum usable (for high performance). Thus using the PPS output (~270 ohm is series with a 5V 74AC04 output) from a Synergy evaluation board that uses an M12M or M12+ GPS timing receiver to drive the inputs (with a 0-750mV signal) of a 5370A or 5370B is well within the recommended input signal range for high performance. This avoids having to adding an external 5V 50 ohm driver that some would use. Bruce Bob Camp wrote: Hi So exactly how did you know that I bought a (cheap) 5370B a few hours ago on the e-place and was just about to ask about how best to use it. H... Bob On Feb 27, 2010, at 7:01 PM, Bruce Griffiths wrote: The attached excerpts from the 5370A and 5370B manuals indicate that for best performance, that the common practice of driving the 5370A/B 1x inputs directly from a 5V CMOS logic signal is a bad idea. For the 5370A attenuating the 5V CMOS signal to a 1V swing with the threshold set to 0.5V is close to optimum. An input signal with limits of 0V and +1.4V with a trigger threshold of 0.7V is the maximum usable (for high performance). An input signal with limits of 0V and +0.3V with a trigger threshold of 0.15V is the minimum usable (for high performance). For the 5370A attenuating the 5V CMOS
Re: [time-nuts] Achieving maximum performance when driving 5370A/B inputs
Mike Feher wrote: In general, what about the old National damn fast and super damn fast LH0032 LH0033? I used to use a lot of those in my designs many years ago. - Mike Mike B. Feher, N4FS 89 Arnold Blvd. Howell, NJ, 07731 732-886-5960 The LH0032 was a fast FET input opamp. I presume you meant the LH0033 and LH0063? Their slew rate is adequate to ensure that the 5370A/B trigger jitter is insignificant. However they need a negative supply as well as the positive supply when being driven by a 3.3V or 5V CMOS output. Bruce ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] Achieving maximum performance when driving 5370A/B inputs
Actually there are miniature twinax style connectors, for example: http://www.amphenolrf.com/products/twinbnc.asp?N=0sid=4B8860805409E17F; http://www.amphenolrf.com/products/twinbnc.asp?N=0sid=4B8860805409E17F; Bruce Bob Camp wrote: Hi I don't even have the counter and already we're butchering it The big issue is suitable twin-ax connectors and cable. I have both, but they are *big*. They never really made it into the world of miniature connectors and miniature cable. Shielded twisted pair would be another option. That eliminates the cable as an issue. Small connectors (BNC drop in) are still an issue though. Bob On Feb 27, 2010, at 9:48 PM, Bruce Griffiths wrote: Since the input amplifier and trigger circuit are located on a small daughter board it wouldn't be too difficult to replace this with an LVDS to CML stage. The only remaining isue would be what input connector to use (twinax??, SATA??). Bruce Bob Camp wrote: Hi Gee, LVDS what an unusual approach :) It would be nice if these instruments had a balanced input. Common mode noise is indeed an issue in a lot of cases. Of course wrapping the coax headed to the counter 10X around a fairly large core can help things a bit. Bob On Feb 27, 2010, at 9:32 PM, Bruce Griffiths wrote: If one is feeling paranoid about ground loop noise (and wishes to avoid transformers, optoisolators , or fibre optics), etc one could always use an LVDS driver with a batter powered(?) LVDS to CMOS receiver/translator right at the 5370A/B input BNC connector. This may be useful for a DMTD system that uses a 5370A/B. Bruce Bob Camp wrote: Hi AC cmos will easily drive an L pad to match a 50 ohm cable at these levels. That's true at either 3.3 or at 5.0 volts. There are a lot of cmos families out there that beat AC for speed and match the output drive capability. Bob On Feb 27, 2010, at 9:12 PM, Bruce Griffiths wrote: 1) One method with 5V CMOS is to add a resistive voltage divider at the CMOS driver output with a 50 ohm output impedance at the tap that drives the 5370A/B input. 2) If one has a 5V 50 ohm driver (eg Thunderbolt PPS output) use a 50 ohm attenuator at the 5370A/B input. For a 5370A an attenuation of at least 11dB is required. For a 5370B an attenuation of at least 3dB is required. 3) One can always use the 10x input attenuation setting built in to the 5370A/B however this reduces the signal swing to 0.5V at the trigger amplifier input (5V CMOS input). 4) Attenuate the output of the logic signal by a factor of 2 and use an npn emitter follower to drive the 50 ohm load. 5) Use 3.3V CMOS signal levels for the 5370B. 6) Use a current mode emitter or source coupled switch to drive the 5370A/B input. The switching jitter of the above drivers will be much lower than the internal noise of the 5370A/B as long as HCMOS or faster logic is employed. Bruce Bob Camp wrote: Hi Which *still* carefully avoids the issue of how . Bob On Feb 27, 2010, at 8:52 PM, Bruce Griffiths wrote: Oops! a small correction (2nd paragraph): For the 5370A attenuating the 5V CMOS signal to a 1V swing with the threshold set to 0.5V is close to optimum. An input signal with limits of 0V and +1.4V with a trigger threshold of 0.7V is the maximum usable (for high performance). An input signal with limits of 0V and +0.3V with a trigger threshold of 0.15V is the minimum usable (for high performance). For the 5370B attenuating the 5V CMOS signal to a 2V swing with the threshold set to 1V is close to optimum. An input signal with limits of 0V and +3.5V with a trigger threshold of 0.7V is the maximum usable (for high performance). An input signal with limits of 0V and +0.3V with a trigger threshold of 0.15V is the minimum usable (for high performance). Thus using the PPS output (~270 ohm is series with a 5V 74AC04 output) from a Synergy evaluation board that uses an M12M or M12+ GPS timing receiver to drive the inputs (with a 0-750mV signal) of a 5370A or 5370B is well within the recommended input signal range for high performance. This avoids having to adding an external 5V 50 ohm driver that some would use. Bruce Bob Camp wrote: Hi So exactly how did you know that I bought a (cheap) 5370B a few hours ago on the e-place and was just about to ask about how best to use it. H... Bob On Feb 27, 2010, at 7:01 PM, Bruce Griffiths wrote: The attached excerpts from the 5370A and 5370B manuals indicate that for best performance, that the common practice of driving the 5370A/B 1x inputs directly from a 5V CMOS logic signal is a bad idea. For the 5370A attenuating the 5V CMOS signal to a 1V swing with the threshold set to 0.5V is close to optimum. An input signal with limits of 0V and +1.4V with a trigger threshold of 0.7V is the maximum usable (for high performance). An input signal
Re: [time-nuts] Achieving maximum performance when driving 5370A/B inputs
Hi Sure never seen any of them on any gear in my junk pile. I also never seen a customer ask for them as an output connector on an oscillator. I wonder how common they actually are. Bob On Feb 27, 2010, at 9:59 PM, Bruce Griffiths wrote: Actually there are miniature twinax style connectors, for example: http://www.amphenolrf.com/products/twinbnc.asp?N=0sid=4B8860805409E17F; http://www.amphenolrf.com/products/twinbnc.asp?N=0sid=4B8860805409E17F; Bruce Bob Camp wrote: Hi I don't even have the counter and already we're butchering it The big issue is suitable twin-ax connectors and cable. I have both, but they are *big*. They never really made it into the world of miniature connectors and miniature cable. Shielded twisted pair would be another option. That eliminates the cable as an issue. Small connectors (BNC drop in) are still an issue though. Bob On Feb 27, 2010, at 9:48 PM, Bruce Griffiths wrote: Since the input amplifier and trigger circuit are located on a small daughter board it wouldn't be too difficult to replace this with an LVDS to CML stage. The only remaining isue would be what input connector to use (twinax??, SATA??). Bruce Bob Camp wrote: Hi Gee, LVDS what an unusual approach :) It would be nice if these instruments had a balanced input. Common mode noise is indeed an issue in a lot of cases. Of course wrapping the coax headed to the counter 10X around a fairly large core can help things a bit. Bob On Feb 27, 2010, at 9:32 PM, Bruce Griffiths wrote: If one is feeling paranoid about ground loop noise (and wishes to avoid transformers, optoisolators , or fibre optics), etc one could always use an LVDS driver with a batter powered(?) LVDS to CMOS receiver/translator right at the 5370A/B input BNC connector. This may be useful for a DMTD system that uses a 5370A/B. Bruce Bob Camp wrote: Hi AC cmos will easily drive an L pad to match a 50 ohm cable at these levels. That's true at either 3.3 or at 5.0 volts. There are a lot of cmos families out there that beat AC for speed and match the output drive capability. Bob On Feb 27, 2010, at 9:12 PM, Bruce Griffiths wrote: 1) One method with 5V CMOS is to add a resistive voltage divider at the CMOS driver output with a 50 ohm output impedance at the tap that drives the 5370A/B input. 2) If one has a 5V 50 ohm driver (eg Thunderbolt PPS output) use a 50 ohm attenuator at the 5370A/B input. For a 5370A an attenuation of at least 11dB is required. For a 5370B an attenuation of at least 3dB is required. 3) One can always use the 10x input attenuation setting built in to the 5370A/B however this reduces the signal swing to 0.5V at the trigger amplifier input (5V CMOS input). 4) Attenuate the output of the logic signal by a factor of 2 and use an npn emitter follower to drive the 50 ohm load. 5) Use 3.3V CMOS signal levels for the 5370B. 6) Use a current mode emitter or source coupled switch to drive the 5370A/B input. The switching jitter of the above drivers will be much lower than the internal noise of the 5370A/B as long as HCMOS or faster logic is employed. Bruce Bob Camp wrote: Hi Which *still* carefully avoids the issue of how . Bob On Feb 27, 2010, at 8:52 PM, Bruce Griffiths wrote: Oops! a small correction (2nd paragraph): For the 5370A attenuating the 5V CMOS signal to a 1V swing with the threshold set to 0.5V is close to optimum. An input signal with limits of 0V and +1.4V with a trigger threshold of 0.7V is the maximum usable (for high performance). An input signal with limits of 0V and +0.3V with a trigger threshold of 0.15V is the minimum usable (for high performance). For the 5370B attenuating the 5V CMOS signal to a 2V swing with the threshold set to 1V is close to optimum. An input signal with limits of 0V and +3.5V with a trigger threshold of 0.7V is the maximum usable (for high performance). An input signal with limits of 0V and +0.3V with a trigger threshold of 0.15V is the minimum usable (for high performance). Thus using the PPS output (~270 ohm is series with a 5V 74AC04 output) from a Synergy evaluation board that uses an M12M or M12+ GPS timing receiver to drive the inputs (with a 0-750mV signal) of a 5370A or 5370B is well within the recommended input signal range for high performance. This avoids having to adding an external 5V 50 ohm driver that some would use. Bruce Bob Camp wrote: Hi So exactly how did you know that I bought a (cheap) 5370B a few hours ago on the e-place and was just about to ask about how best to use it. H... Bob On Feb 27, 2010, at 7:01 PM, Bruce Griffiths wrote: The attached excerpts from the 5370A and 5370B manuals
Re: [time-nuts] Achieving maximum performance when driving 5370A/B inputs
You could look at a surplus F16 (probably wont fit in your garage though) or similar STP was heavily used in MIL STD 1553 avionics buses. Bruce Bob Camp wrote: Hi Sure never seen any of them on any gear in my junk pile. I also never seen a customer ask for them as an output connector on an oscillator. I wonder how common they actually are. Bob On Feb 27, 2010, at 9:59 PM, Bruce Griffiths wrote: Actually there are miniature twinax style connectors, for example: http://www.amphenolrf.com/products/twinbnc.asp?N=0sid=4B8860805409E17F; http://www.amphenolrf.com/products/twinbnc.asp?N=0sid=4B8860805409E17F; Bruce Bob Camp wrote: Hi I don't even have the counter and already we're butchering it The big issue is suitable twin-ax connectors and cable. I have both, but they are *big*. They never really made it into the world of miniature connectors and miniature cable. Shielded twisted pair would be another option. That eliminates the cable as an issue. Small connectors (BNC drop in) are still an issue though. Bob On Feb 27, 2010, at 9:48 PM, Bruce Griffiths wrote: Since the input amplifier and trigger circuit are located on a small daughter board it wouldn't be too difficult to replace this with an LVDS to CML stage. The only remaining isue would be what input connector to use (twinax??, SATA??). Bruce Bob Camp wrote: Hi Gee, LVDS what an unusual approach :) It would be nice if these instruments had a balanced input. Common mode noise is indeed an issue in a lot of cases. Of course wrapping the coax headed to the counter 10X around a fairly large core can help things a bit. Bob On Feb 27, 2010, at 9:32 PM, Bruce Griffiths wrote: If one is feeling paranoid about ground loop noise (and wishes to avoid transformers, optoisolators , or fibre optics), etc one could always use an LVDS driver with a batter powered(?) LVDS to CMOS receiver/translator right at the 5370A/B input BNC connector. This may be useful for a DMTD system that uses a 5370A/B. Bruce Bob Camp wrote: Hi AC cmos will easily drive an L pad to match a 50 ohm cable at these levels. That's true at either 3.3 or at 5.0 volts. There are a lot of cmos families out there that beat AC for speed and match the output drive capability. Bob On Feb 27, 2010, at 9:12 PM, Bruce Griffiths wrote: 1) One method with 5V CMOS is to add a resistive voltage divider at the CMOS driver output with a 50 ohm output impedance at the tap that drives the 5370A/B input. 2) If one has a 5V 50 ohm driver (eg Thunderbolt PPS output) use a 50 ohm attenuator at the 5370A/B input. For a 5370A an attenuation of at least 11dB is required. For a 5370B an attenuation of at least 3dB is required. 3) One can always use the 10x input attenuation setting built in to the 5370A/B however this reduces the signal swing to 0.5V at the trigger amplifier input (5V CMOS input). 4) Attenuate the output of the logic signal by a factor of 2 and use an npn emitter follower to drive the 50 ohm load. 5) Use 3.3V CMOS signal levels for the 5370B. 6) Use a current mode emitter or source coupled switch to drive the 5370A/B input. The switching jitter of the above drivers will be much lower than the internal noise of the 5370A/B as long as HCMOS or faster logic is employed. Bruce Bob Camp wrote: Hi Which *still* carefully avoids the issue of how . Bob On Feb 27, 2010, at 8:52 PM, Bruce Griffiths wrote: Oops! a small correction (2nd paragraph): For the 5370A attenuating the 5V CMOS signal to a 1V swing with the threshold set to 0.5V is close to optimum. An input signal with limits of 0V and +1.4V with a trigger threshold of 0.7V is the maximum usable (for high performance). An input signal with limits of 0V and +0.3V with a trigger threshold of 0.15V is the minimum usable (for high performance). For the 5370B attenuating the 5V CMOS signal to a 2V swing with the threshold set to 1V is close to optimum. An input signal with limits of 0V and +3.5V with a trigger threshold of 0.7V is the maximum usable (for high performance). An input signal with limits of 0V and +0.3V with a trigger threshold of 0.15V is the minimum usable (for high performance). Thus using the PPS output (~270 ohm is series with a 5V 74AC04 output) from a Synergy evaluation board that uses an M12M or M12+ GPS timing receiver to drive the inputs (with a 0-750mV signal) of a 5370A or 5370B is well within the recommended input signal range for high performance. This avoids having to adding an external 5V 50 ohm driver that some would use. Bruce Bob Camp wrote: Hi So exactly how did you know that I bought a (cheap) 5370B a few hours ago on the e-place and was just about to ask about how best to use it. H... Bob On Feb 27, 2010, at 7:01 PM, Bruce Griffiths wrote:
Re: [time-nuts] Achieving maximum performance when driving 5370A/B inputs
Hi MIght have to move a few things in the shed to fin in an F16. If they were used in quantity there aught to be cable and connectors out there. The only reason I have the stuff I do is good old IBM and their approach to networking back in the old days. It would be tough to properly drive an R-390 otherwise. Bob On Feb 27, 2010, at 10:10 PM, Bruce Griffiths wrote: You could look at a surplus F16 (probably wont fit in your garage though) or similar STP was heavily used in MIL STD 1553 avionics buses. Bruce Bob Camp wrote: Hi Sure never seen any of them on any gear in my junk pile. I also never seen a customer ask for them as an output connector on an oscillator. I wonder how common they actually are. Bob On Feb 27, 2010, at 9:59 PM, Bruce Griffiths wrote: Actually there are miniature twinax style connectors, for example: http://www.amphenolrf.com/products/twinbnc.asp?N=0sid=4B8860805409E17F; http://www.amphenolrf.com/products/twinbnc.asp?N=0sid=4B8860805409E17F; Bruce Bob Camp wrote: Hi I don't even have the counter and already we're butchering it The big issue is suitable twin-ax connectors and cable. I have both, but they are *big*. They never really made it into the world of miniature connectors and miniature cable. Shielded twisted pair would be another option. That eliminates the cable as an issue. Small connectors (BNC drop in) are still an issue though. Bob On Feb 27, 2010, at 9:48 PM, Bruce Griffiths wrote: Since the input amplifier and trigger circuit are located on a small daughter board it wouldn't be too difficult to replace this with an LVDS to CML stage. The only remaining isue would be what input connector to use (twinax??, SATA??). Bruce Bob Camp wrote: Hi Gee, LVDS what an unusual approach :) It would be nice if these instruments had a balanced input. Common mode noise is indeed an issue in a lot of cases. Of course wrapping the coax headed to the counter 10X around a fairly large core can help things a bit. Bob On Feb 27, 2010, at 9:32 PM, Bruce Griffiths wrote: If one is feeling paranoid about ground loop noise (and wishes to avoid transformers, optoisolators , or fibre optics), etc one could always use an LVDS driver with a batter powered(?) LVDS to CMOS receiver/translator right at the 5370A/B input BNC connector. This may be useful for a DMTD system that uses a 5370A/B. Bruce Bob Camp wrote: Hi AC cmos will easily drive an L pad to match a 50 ohm cable at these levels. That's true at either 3.3 or at 5.0 volts. There are a lot of cmos families out there that beat AC for speed and match the output drive capability. Bob On Feb 27, 2010, at 9:12 PM, Bruce Griffiths wrote: 1) One method with 5V CMOS is to add a resistive voltage divider at the CMOS driver output with a 50 ohm output impedance at the tap that drives the 5370A/B input. 2) If one has a 5V 50 ohm driver (eg Thunderbolt PPS output) use a 50 ohm attenuator at the 5370A/B input. For a 5370A an attenuation of at least 11dB is required. For a 5370B an attenuation of at least 3dB is required. 3) One can always use the 10x input attenuation setting built in to the 5370A/B however this reduces the signal swing to 0.5V at the trigger amplifier input (5V CMOS input). 4) Attenuate the output of the logic signal by a factor of 2 and use an npn emitter follower to drive the 50 ohm load. 5) Use 3.3V CMOS signal levels for the 5370B. 6) Use a current mode emitter or source coupled switch to drive the 5370A/B input. The switching jitter of the above drivers will be much lower than the internal noise of the 5370A/B as long as HCMOS or faster logic is employed. Bruce Bob Camp wrote: Hi Which *still* carefully avoids the issue of how . Bob On Feb 27, 2010, at 8:52 PM, Bruce Griffiths wrote: Oops! a small correction (2nd paragraph): For the 5370A attenuating the 5V CMOS signal to a 1V swing with the threshold set to 0.5V is close to optimum. An input signal with limits of 0V and +1.4V with a trigger threshold of 0.7V is the maximum usable (for high performance). An input signal with limits of 0V and +0.3V with a trigger threshold of 0.15V is the minimum usable (for high performance). For the 5370B attenuating the 5V CMOS signal to a 2V swing with the threshold set to 1V is close to optimum. An input signal with limits of 0V and +3.5V with a trigger threshold of 0.7V is the maximum usable (for high performance). An input signal with limits of 0V and +0.3V with a trigger threshold of 0.15V is the minimum usable (for high performance). Thus using the PPS output (~270 ohm is series with a 5V 74AC04 output) from a Synergy evaluation board that uses an M12M or M12+ GPS
[time-nuts] Achieving maximum performance when driving 5370A/B inputs
R-390 or S/390? The R-390 receiver (designed by Collins) is probably worth more today than an S390. ;-) ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] Achieving maximum performance when driving 5370A/B inputs
here is a two center pin type of BNC, presumably for a balanced twisted pair or twin ax type cable. The shape of the dielectric allows proper mechanical mating. Stan, W1LE Cape Cod Bob Camp wrote: Hi I don't even have the counter and already we're butchering it The big issue is suitable twin-ax connectors and cable. I have both, but they are *big*. They never really made it into the world of miniature connectors and miniature cable. Shielded twisted pair would be another option. That eliminates the cable as an issue. Small connectors (BNC drop in) are still an issue though. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] Achieving maximum performance when driving 5370A/B inputs
I have a bnc type connector with two pins inside the shield on a FTS cesium standard labeled DS1 must be a phone industry jack. Stanley - Original Message From: Bob Camp li...@rtty.us To: Discussion of precise time and frequency measurement time-nuts@febo.com Sent: Sat, February 27, 2010 8:53:16 PM Subject: Re: [time-nuts] Achieving maximum performance when driving 5370A/B inputs Hi I don't even have the counter and already we're butchering it The big issue is suitable twin-ax connectors and cable. I have both, but they are *big*. They never really made it into the world of miniature connectors and miniature cable. Shielded twisted pair would be another option. That eliminates the cable as an issue. Small connectors (BNC drop in) are still an issue though. Bob On Feb 27, 2010, at 9:48 PM, Bruce Griffiths wrote: Since the input amplifier and trigger circuit are located on a small daughter board it wouldn't be too difficult to replace this with an LVDS to CML stage. The only remaining isue would be what input connector to use (twinax??, SATA??). Bruce Bob Camp wrote: Hi Gee, LVDS what an unusual approach :) It would be nice if these instruments had a balanced input. Common mode noise is indeed an issue in a lot of cases. Of course wrapping the coax headed to the counter 10X around a fairly large core can help things a bit. Bob On Feb 27, 2010, at 9:32 PM, Bruce Griffiths wrote: If one is feeling paranoid about ground loop noise (and wishes to avoid transformers, optoisolators , or fibre optics), etc one could always use an LVDS driver with a batter powered(?) LVDS to CMOS receiver/translator right at the 5370A/B input BNC connector. This may be useful for a DMTD system that uses a 5370A/B. Bruce Bob Camp wrote: Hi AC cmos will easily drive an L pad to match a 50 ohm cable at these levels. That's true at either 3.3 or at 5.0 volts. There are a lot of cmos families out there that beat AC for speed and match the output drive capability. Bob On Feb 27, 2010, at 9:12 PM, Bruce Griffiths wrote: 1) One method with 5V CMOS is to add a resistive voltage divider at the CMOS driver output with a 50 ohm output impedance at the tap that drives the 5370A/B input. 2) If one has a 5V 50 ohm driver (eg Thunderbolt PPS output) use a 50 ohm attenuator at the 5370A/B input. For a 5370A an attenuation of at least 11dB is required. For a 5370B an attenuation of at least 3dB is required. 3) One can always use the 10x input attenuation setting built in to the 5370A/B however this reduces the signal swing to 0.5V at the trigger amplifier input (5V CMOS input). 4) Attenuate the output of the logic signal by a factor of 2 and use an npn emitter follower to drive the 50 ohm load. 5) Use 3.3V CMOS signal levels for the 5370B. 6) Use a current mode emitter or source coupled switch to drive the 5370A/B input. The switching jitter of the above drivers will be much lower than the internal noise of the 5370A/B as long as HCMOS or faster logic is employed. Bruce Bob Camp wrote: Hi Which *still* carefully avoids the issue of how . Bob On Feb 27, 2010, at 8:52 PM, Bruce Griffiths wrote: Oops! a small correction (2nd paragraph): For the 5370A attenuating the 5V CMOS signal to a 1V swing with the threshold set to 0.5V is close to optimum. An input signal with limits of 0V and +1.4V with a trigger threshold of 0.7V is the maximum usable (for high performance). An input signal with limits of 0V and +0.3V with a trigger threshold of 0.15V is the minimum usable (for high performance). For the 5370B attenuating the 5V CMOS signal to a 2V swing with the threshold set to 1V is close to optimum. An input signal with limits of 0V and +3.5V with a trigger threshold of 0.7V is the maximum usable (for high performance). An input signal with limits of 0V and +0.3V with a trigger threshold of 0.15V is the minimum usable (for high performance). Thus using the PPS output (~270 ohm is series with a 5V 74AC04 output) from a Synergy evaluation board that uses an M12M or M12+ GPS timing receiver to drive the inputs (with a 0-750mV signal) of a 5370A or 5370B is well within the recommended input signal range for high performance. This avoids having to adding an external 5V 50 ohm driver that some would use. Bruce Bob Camp wrote: Hi So exactly how did you know that I bought a (cheap) 5370B a few hours ago on the e-place and was just about to ask about how best to use it. H... Bob On Feb 27, 2010, at 7:01 PM, Bruce Griffiths wrote: The attached excerpts from the 5370A and 5370B manuals indicate that for best performance, that the common practice of driving the 5370A/B 1x inputs directly from a 5V CMOS logic signal is a bad idea. For the 5370A
Re: [time-nuts] Achieving maximum performance when driving 5370A/B inputs
Mike Feher wrote: In general, what about the old National damn fast and super damn fast LH0032 LH0033? I used to use a lot of those in my designs many years ago. - Mike Gotta really decouple the power supplies on those puppies... ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] Achieving maximum performance when driving 5370A/B inputs
Bob Camp wrote: Hi Sure never seen any of them on any gear in my junk pile. I also never seen a customer ask for them as an output connector on an oscillator. I wonder how common they actually are. Bob On Feb 27, 2010, at 9:59 PM, Bruce Griffiths wrote: Actually there are miniature twinax style connectors, for example: http://www.amphenolrf.com/products/twinbnc.asp?N=0sid=4B8860805409E17F; http://www.amphenolrf.com/products/twinbnc.asp?N=0sid=4B8860805409E17F; Bruce Bob Camp wrote: There's a variety of these kind of things. You see them in MIL-STD-1553B systems, among others. Triax is also fairly common as a connector for shielded twisted pair. There are also twisted pair inserts for the DB-25 sized shell (actually a quad pair with 4 inserts). The one that has one pin and one socket on each side is a much better strategy than the one that has 2 pins on one connector and 2 sockets on the other. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] Achieving maximum performance when driving 5370A/B inputs
These were used on some measuring instruments to provide a balance 'guarded' input. The shield around the balanced conductors provided a ground between the DUT and the measuring equipment that was not connected to the input. IIRC this was for very low level signals. 73 Glenn WB4UIV At 10:06 PM 2/27/2010, you wrote: Hi Sure never seen any of them on any gear in my junk pile. I also never seen a customer ask for them as an output connector on an oscillator. I wonder how common they actually are. Bob On Feb 27, 2010, at 9:59 PM, Bruce Griffiths wrote: Actually there are miniature twinax style connectors, for example: http://www.amphenolrf.com/products/twinbnc.asp?N=0sid=4B8860805409E17F; http://www.amphenolrf.com/products/twinbnc.asp?N=0sid=4B8860805409E17F; Bruce Bob Camp wrote: Hi I don't even have the counter and already we're butchering it The big issue is suitable twin-ax connectors and cable. I have both, but they are *big*. They never really made it into the world of miniature connectors and miniature cable. Shielded twisted pair would be another option. That eliminates the cable as an issue. Small connectors (BNC drop in) are still an issue though. Bob On Feb 27, 2010, at 9:48 PM, Bruce Griffiths wrote: Since the input amplifier and trigger circuit are located on a small daughter board it wouldn't be too difficult to replace this with an LVDS to CML stage. The only remaining isue would be what input connector to use (twinax??, SATA??). Bruce Bob Camp wrote: Hi Gee, LVDS what an unusual approach :) It would be nice if these instruments had a balanced input. Common mode noise is indeed an issue in a lot of cases. Of course wrapping the coax headed to the counter 10X around a fairly large core can help things a bit. Bob On Feb 27, 2010, at 9:32 PM, Bruce Griffiths wrote: If one is feeling paranoid about ground loop noise (and wishes to avoid transformers, optoisolators , or fibre optics), etc one could always use an LVDS driver with a batter powered(?) LVDS to CMOS receiver/translator right at the 5370A/B input BNC connector. This may be useful for a DMTD system that uses a 5370A/B. Bruce Bob Camp wrote: Hi AC cmos will easily drive an L pad to match a 50 ohm cable at these levels. That's true at either 3.3 or at 5.0 volts. There are a lot of cmos families out there that beat AC for speed and match the output drive capability. Bob On Feb 27, 2010, at 9:12 PM, Bruce Griffiths wrote: 1) One method with 5V CMOS is to add a resistive voltage divider at the CMOS driver output with a 50 ohm output impedance at the tap that drives the 5370A/B input. 2) If one has a 5V 50 ohm driver (eg Thunderbolt PPS output) use a 50 ohm attenuator at the 5370A/B input. For a 5370A an attenuation of at least 11dB is required. For a 5370B an attenuation of at least 3dB is required. 3) One can always use the 10x input attenuation setting built in to the 5370A/B however this reduces the signal swing to 0.5V at the trigger amplifier input (5V CMOS input). 4) Attenuate the output of the logic signal by a factor of 2 and use an npn emitter follower to drive the 50 ohm load. 5) Use 3.3V CMOS signal levels for the 5370B. 6) Use a current mode emitter or source coupled switch to drive the 5370A/B input. The switching jitter of the above drivers will be much lower than the internal noise of the 5370A/B as long as HCMOS or faster logic is employed. Bruce Bob Camp wrote: Hi Which *still* carefully avoids the issue of how . Bob On Feb 27, 2010, at 8:52 PM, Bruce Griffiths wrote: Oops! a small correction (2nd paragraph): For the 5370A attenuating the 5V CMOS signal to a 1V swing with the threshold set to 0.5V is close to optimum. An input signal with limits of 0V and +1.4V with a trigger threshold of 0.7V is the maximum usable (for high performance). An input signal with limits of 0V and +0.3V with a trigger threshold of 0.15V is the minimum usable (for high performance). For the 5370B attenuating the 5V CMOS signal to a 2V swing with the threshold set to 1V is close to optimum. An input signal with limits of 0V and +3.5V with a trigger threshold of 0.7V is the maximum usable (for high performance). An input signal with limits of 0V and +0.3V with a trigger threshold of 0.15V is the minimum usable (for high performance). Thus using the PPS output (~270 ohm is series with a 5V 74AC04 output) from a Synergy evaluation board that uses an M12M or M12+ GPS timing receiver to drive the inputs (with a 0-750mV signal) of a 5370A or 5370B is well within the recommended input signal range for high performance. This avoids having to adding an external 5V 50 ohm driver that some would use. Bruce Bob Camp wrote: Hi So exactly how did you know that I bought a (cheap) 5370B a few hours ago on the e-place and was just about to ask about how best to use
Re: [time-nuts] Achieving maximum performance when driving 5370A/B inputs
found a picture of the Twin BNC here: http://drawings.amphenolrf.com/pdf/172.pdf ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
[time-nuts] Achieving maximum performance when driving 5370A/B inputs
If it's the one that I think it is... look closely at the photo. The shafts on two of the pots are sheared off at the panel. These are the display update control and the external arming level control. These were custom HP pots with a funky (and delicate) switch. They had brittle plastic shafts.Gee, how do I know this... could it be that a large percentage of the 5370's for sale have the same defect? Luckily those controls are not too critical for normal operation. They can be replaced with regular (switchless) pots if you jumper the switch pads correctly. Be careful, there were two different layouts to those controls. -- So exactly how did you know that I bought a (cheap) 5370B a few hours ago on the e-place _ Hotmail: Trusted email with powerful SPAM protection. http://clk.atdmt.com/GBL/go/201469227/direct/01/ ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] Achieving maximum performance when driving 5370A/B inputs
Is that buttermilk or blueberry batter? :-) Don - Original Message - From: Bruce Griffiths bruce.griffi...@xtra.co.nz To: Discussion of precise time and frequency measurement time-nuts@febo.com Sent: Saturday, February 27, 2010 7:32 PM Subject: Re: [time-nuts] Achieving maximum performance when driving 5370A/B inputs If one is feeling paranoid about ground loop noise (and wishes to avoid transformers, optoisolators , or fibre optics), etc one could always use an LVDS driver with a batter powered(?) LVDS to CMOS receiver/translator right at the 5370A/B input BNC connector. This may be useful for a DMTD system that uses a 5370A/B. Bruce Bob Camp wrote: Hi AC cmos will easily drive an L pad to match a 50 ohm cable at these levels. That's true at either 3.3 or at 5.0 volts. There are a lot of cmos families out there that beat AC for speed and match the output drive capability. Bob On Feb 27, 2010, at 9:12 PM, Bruce Griffiths wrote: 1) One method with 5V CMOS is to add a resistive voltage divider at the CMOS driver output with a 50 ohm output impedance at the tap that drives the 5370A/B input. 2) If one has a 5V 50 ohm driver (eg Thunderbolt PPS output) use a 50 ohm attenuator at the 5370A/B input. For a 5370A an attenuation of at least 11dB is required. For a 5370B an attenuation of at least 3dB is required. 3) One can always use the 10x input attenuation setting built in to the 5370A/B however this reduces the signal swing to 0.5V at the trigger amplifier input (5V CMOS input). 4) Attenuate the output of the logic signal by a factor of 2 and use an npn emitter follower to drive the 50 ohm load. 5) Use 3.3V CMOS signal levels for the 5370B. 6) Use a current mode emitter or source coupled switch to drive the 5370A/B input. The switching jitter of the above drivers will be much lower than the internal noise of the 5370A/B as long as HCMOS or faster logic is employed. Bruce Bob Camp wrote: Hi Which *still* carefully avoids the issue of how . Bob On Feb 27, 2010, at 8:52 PM, Bruce Griffiths wrote: Oops! a small correction (2nd paragraph): For the 5370A attenuating the 5V CMOS signal to a 1V swing with the threshold set to 0.5V is close to optimum. An input signal with limits of 0V and +1.4V with a trigger threshold of 0.7V is the maximum usable (for high performance). An input signal with limits of 0V and +0.3V with a trigger threshold of 0.15V is the minimum usable (for high performance). For the 5370B attenuating the 5V CMOS signal to a 2V swing with the threshold set to 1V is close to optimum. An input signal with limits of 0V and +3.5V with a trigger threshold of 0.7V is the maximum usable (for high performance). An input signal with limits of 0V and +0.3V with a trigger threshold of 0.15V is the minimum usable (for high performance). Thus using the PPS output (~270 ohm is series with a 5V 74AC04 output) from a Synergy evaluation board that uses an M12M or M12+ GPS timing receiver to drive the inputs (with a 0-750mV signal) of a 5370A or 5370B is well within the recommended input signal range for high performance. This avoids having to adding an external 5V 50 ohm driver that some would use. Bruce Bob Camp wrote: Hi So exactly how did you know that I bought a (cheap) 5370B a few hours ago on the e-place and was just about to ask about how best to use it. H... Bob On Feb 27, 2010, at 7:01 PM, Bruce Griffiths wrote: The attached excerpts from the 5370A and 5370B manuals indicate that for best performance, that the common practice of driving the 5370A/B 1x inputs directly from a 5V CMOS logic signal is a bad idea. For the 5370A attenuating the 5V CMOS signal to a 1V swing with the threshold set to 0.5V is close to optimum. An input signal with limits of 0V and +1.4V with a trigger threshold of 0.7V is the maximum usable (for high performance). An input signal with limits of 0V and +0.3V with a trigger threshold of 0.15V is the minimum usable (for high performance). For the 5370A attenuating the 5V CMOS signal to a 2V swing with the threshold set to 1V is close to optimum. An input signal with limits of 0V and +3.5V with a trigger threshold of 0.7V is the maximum usable (for high performance). An input signal with limits of 0V and +0.3V with a trigger threshold of 0.15V is the minimum usable (for high performance). Bruce 5370ATriggering.png5370BTriggering.png___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe
