Re: [time-nuts] strange behavior of 53230A or is the light on, but nobody in?
Le 19 févr. 2014 à 01:05, Tom Knox a écrit : Thanks Tom and Bob, I have been thinking of contacting Agilent for some time. I think they are a great company with some good products, but there are a few real blind spots in some current products. I also have seen in the past a genuine interest in listening. I would be willing to approach them if I could enlist your help in addressing potential changes to improve the product. Thanks; Thomas Knox If they are steering the VCXXO,OCXO from the Ext. Ref. , then they are in effect calibrating it. Why not remember the applied EFC when they get phase lock? That can be applied when the internal timebase is selected. It couldn't be that they might lose the chance to sell a signal generator ;-), as calibration needs a square wave input, and the Ext. Ref In is ignored. From: li...@rtty.us Date: Tue, 18 Feb 2014 18:00:17 -0500 To: time-nuts@febo.com Subject: Re: [time-nuts] strange behavior of 53230A or is the light on, but nobody in? Hi Well at least this got me digging a little. If you grab a copy of the 53230A spec sheet and look under the external reference input, it’s pretty well described. It will accept 1, 5,10 MHz as an external reference. It will lock over a 1 ppm range with the XO option and 0.1 ppm with the OCXO option. Based on that I’d guess they are still using the same basic PLL approach as on the older counters (5335 era). The “Microsoft Windows inside” sticker on the back of the counter was a bit of a surprise …. No sticker on mine. Bob On Feb 18, 2014, at 11:51 AM, Tom Van Baak (lab) t...@leapsecond.com wrote: TomK, If anyone has technical contacts deep within Agilent, let's see if this issue can be resolved. I would have bought a 53230A when it came out a few years ago but my eval units showed this clock noise problem. That plus the poor quality of the ref out made me think the designers were cutting corners, or had little experience in metrology, or maybe they thought this was ok for a bench instrument. Otherwise it's a really nice counter; the first one from Agilent than can actually do ADEV properly (since it is a time stamping counter). I should dig out my old data and send it to you. Maybe as group we can help them fix the problem. /tvb On Feb 18, 2014, at 12:10 AM, Tom Knox act...@hotmail.com wrote: I have asked Agilent if stock versions of the 53230A and 53132A switched the internal oscillator out of circuit with an Ext Ref signal applied. I thought Agilent's engineer was intentionally vague but said the oscillators were indeed switched out of circuit on the counter with Ext Ref signal applied. These questions were related to several 53132A's I have seen configured with a small board back near the Ext Ref input (OPT H01 I think) that appeared to Switch the internal reference out of circuit. Agilent would not share information on the option. My question to Agilent is why sell an option and be unwilling to say what it does or how your stock unit functions? Thomas Knox From: t...@leapsecond.com Date: Mon, 17 Feb 2014 09:38:28 -1000 To: time-nuts@febo.com Subject: Re: [time-nuts] strange behavior of 53230A or is the light on, but nobody in? Bob, I'm wondering if you (or any else) has measured the PLL performance of the 53230-series? I agree it will clean up the crud but this assumes the ext ref is dirtier than the internal osc. What I found instead was that if you use a good external ref the PLL actually makes it worse. This was very disappointing. The XO version of the counter performed worse than the OCXO version even with a maser as the ext reference. Did your reading of the schematic show a way to directly use the ext ref, bypassing the noisy PLL? The other thing I found was that the ref out signal was a very polluted copy of the ref in. /tvb (i5s) On Feb 17, 2014, at 7:04 AM, Bob Camp li...@rtty.us wrote: Hi If you dig into the schematics (when they supplied them … ): The external reference goes into a phase detector. It’s one of those digital ones that can lock up to many inputs. You could feed 3. MHz in as a standard input as well as 0.5, 1, 2.5, 5, and 10 MHz. The internal oscillator (or an internal oscillator) is phase locked to the external input through a fairly narrow analog loop. The idea is to clean up the crud on the standard line. With no external reference, the PLL drops out and you go back to what ever the local reference is. Yes there’s a little more to it than that and no the circuit is not exactly the same on every counter HP ever made. Bob On Feb 17, 2014, at 7:55 AM, wb6bnq wb6...@cox.net wrote: Hi Mike, The most likely answer is when you select external time base for an input, it disables the connection for the internal oscillator. The external input signal is probably also routed straight
Re: [time-nuts] strange behavior of 53230A or is the light on, but nobody in?
Mike, They are already giving you another way to calibrate the unit, different from how you think they should have done it and you are pulling out the statist card and accusing them of being greedy capitalists? Come on, thats backseat driving. Be happy they invested millions of their own money and put out a more or less affordable new counter in a market flooded with good low-cost used counters. Bye, Said Sent From iPhone On Feb 19, 2014, at 0:33, mike cook michael.c...@sfr.fr wrote: Le 19 févr. 2014 à 01:05, Tom Knox a écrit : Thanks Tom and Bob, I have been thinking of contacting Agilent for some time. I think they are a great company with some good products, but there are a few real blind spots in some current products. I also have seen in the past a genuine interest in listening. I would be willing to approach them if I could enlist your help in addressing potential changes to improve the product. Thanks; Thomas Knox If they are steering the VCXXO,OCXO from the Ext. Ref. , then they are in effect calibrating it. Why not remember the applied EFC when they get phase lock? That can be applied when the internal timebase is selected. It couldn't be that they might lose the chance to sell a signal generator ;-), as calibration needs a square wave input, and the Ext. Ref In is ignored. From: li...@rtty.us Date: Tue, 18 Feb 2014 18:00:17 -0500 To: time-nuts@febo.com Subject: Re: [time-nuts] strange behavior of 53230A or is the light on, but nobody in? Hi Well at least this got me digging a little. If you grab a copy of the 53230A spec sheet and look under the external reference input, it’s pretty well described. It will accept 1, 5,10 MHz as an external reference. It will lock over a 1 ppm range with the XO option and 0.1 ppm with the OCXO option. Based on that I’d guess they are still using the same basic PLL approach as on the older counters (5335 era). The “Microsoft Windows inside” sticker on the back of the counter was a bit of a surprise …. No sticker on mine. Bob On Feb 18, 2014, at 11:51 AM, Tom Van Baak (lab) t...@leapsecond.com wrote: TomK, If anyone has technical contacts deep within Agilent, let's see if this issue can be resolved. I would have bought a 53230A when it came out a few years ago but my eval units showed this clock noise problem. That plus the poor quality of the ref out made me think the designers were cutting corners, or had little experience in metrology, or maybe they thought this was ok for a bench instrument. Otherwise it's a really nice counter; the first one from Agilent than can actually do ADEV properly (since it is a time stamping counter). I should dig out my old data and send it to you. Maybe as group we can help them fix the problem. /tvb On Feb 18, 2014, at 12:10 AM, Tom Knox act...@hotmail.com wrote: I have asked Agilent if stock versions of the 53230A and 53132A switched the internal oscillator out of circuit with an Ext Ref signal applied. I thought Agilent's engineer was intentionally vague but said the oscillators were indeed switched out of circuit on the counter with Ext Ref signal applied. These questions were related to several 53132A's I have seen configured with a small board back near the Ext Ref input (OPT H01 I think) that appeared to Switch the internal reference out of circuit. Agilent would not share information on the option. My question to Agilent is why sell an option and be unwilling to say what it does or how your stock unit functions? Thomas Knox From: t...@leapsecond.com Date: Mon, 17 Feb 2014 09:38:28 -1000 To: time-nuts@febo.com Subject: Re: [time-nuts] strange behavior of 53230A or is the light on, but nobody in? Bob, I'm wondering if you (or any else) has measured the PLL performance of the 53230-series? I agree it will clean up the crud but this assumes the ext ref is dirtier than the internal osc. What I found instead was that if you use a good external ref the PLL actually makes it worse. This was very disappointing. The XO version of the counter performed worse than the OCXO version even with a maser as the ext reference. Did your reading of the schematic show a way to directly use the ext ref, bypassing the noisy PLL? The other thing I found was that the ref out signal was a very polluted copy of the ref in. /tvb (i5s) On Feb 17, 2014, at 7:04 AM, Bob Camp li...@rtty.us wrote: Hi If you dig into the schematics (when they supplied them … ): The external reference goes into a phase detector. It’s one of those digital ones that can lock up to many inputs. You could feed 3. MHz in as a standard input as well as 0.5, 1, 2.5, 5, and 10 MHz. The internal oscillator (or an internal oscillator) is phase locked to the external input through a fairly narrow analog loop. The idea is to clean up the crud on the standard line.
Re: [time-nuts] strange behavior of 53230A or is the light on, but nobody in?
That was a wink, Said, not a howl... Le 19 févr. 2014 à 17:25, Said Jackson a écrit : Mike, They are already giving you another way to calibrate the unit, different from how you think they should have done it and you are pulling out the statist card and accusing them of being greedy capitalists? Come on, thats backseat driving. Be happy they invested millions of their own money and put out a more or less affordable new counter in a market flooded with good low-cost used counters. Bye, Said Sent From iPhone On Feb 19, 2014, at 0:33, mike cook michael.c...@sfr.fr wrote: Le 19 févr. 2014 à 01:05, Tom Knox a écrit : Thanks Tom and Bob, I have been thinking of contacting Agilent for some time. I think they are a great company with some good products, but there are a few real blind spots in some current products. I also have seen in the past a genuine interest in listening. I would be willing to approach them if I could enlist your help in addressing potential changes to improve the product. Thanks; Thomas Knox If they are steering the VCXXO,OCXO from the Ext. Ref. , then they are in effect calibrating it. Why not remember the applied EFC when they get phase lock? That can be applied when the internal timebase is selected. It couldn't be that they might lose the chance to sell a signal generator ;-), as calibration needs a square wave input, and the Ext. Ref In is ignored. From: li...@rtty.us Date: Tue, 18 Feb 2014 18:00:17 -0500 To: time-nuts@febo.com Subject: Re: [time-nuts] strange behavior of 53230A or is the light on, but nobody in? Hi Well at least this got me digging a little. If you grab a copy of the 53230A spec sheet and look under the external reference input, it’s pretty well described. It will accept 1, 5,10 MHz as an external reference. It will lock over a 1 ppm range with the XO option and 0.1 ppm with the OCXO option. Based on that I’d guess they are still using the same basic PLL approach as on the older counters (5335 era). The “Microsoft Windows inside” sticker on the back of the counter was a bit of a surprise …. No sticker on mine. Bob On Feb 18, 2014, at 11:51 AM, Tom Van Baak (lab) t...@leapsecond.com wrote: TomK, If anyone has technical contacts deep within Agilent, let's see if this issue can be resolved. I would have bought a 53230A when it came out a few years ago but my eval units showed this clock noise problem. That plus the poor quality of the ref out made me think the designers were cutting corners, or had little experience in metrology, or maybe they thought this was ok for a bench instrument. Otherwise it's a really nice counter; the first one from Agilent than can actually do ADEV properly (since it is a time stamping counter). I should dig out my old data and send it to you. Maybe as group we can help them fix the problem. /tvb On Feb 18, 2014, at 12:10 AM, Tom Knox act...@hotmail.com wrote: I have asked Agilent if stock versions of the 53230A and 53132A switched the internal oscillator out of circuit with an Ext Ref signal applied. I thought Agilent's engineer was intentionally vague but said the oscillators were indeed switched out of circuit on the counter with Ext Ref signal applied. These questions were related to several 53132A's I have seen configured with a small board back near the Ext Ref input (OPT H01 I think) that appeared to Switch the internal reference out of circuit. Agilent would not share information on the option. My question to Agilent is why sell an option and be unwilling to say what it does or how your stock unit functions? Thomas Knox From: t...@leapsecond.com Date: Mon, 17 Feb 2014 09:38:28 -1000 To: time-nuts@febo.com Subject: Re: [time-nuts] strange behavior of 53230A or is the light on, but nobody in? Bob, I'm wondering if you (or any else) has measured the PLL performance of the 53230-series? I agree it will clean up the crud but this assumes the ext ref is dirtier than the internal osc. What I found instead was that if you use a good external ref the PLL actually makes it worse. This was very disappointing. The XO version of the counter performed worse than the OCXO version even with a maser as the ext reference. Did your reading of the schematic show a way to directly use the ext ref, bypassing the noisy PLL? The other thing I found was that the ref out signal was a very polluted copy of the ref in. /tvb (i5s) On Feb 17, 2014, at 7:04 AM, Bob Camp li...@rtty.us wrote: Hi If you dig into the schematics (when they supplied them … ): The external reference goes into a phase detector. It’s one of those digital ones that can lock up to many inputs. You could feed 3. MHz in as a standard input as well as 0.5, 1, 2.5, 5, and 10 MHz. The internal oscillator (or an internal oscillator) is phase locked to the
Re: [time-nuts] strange behavior of 53230A or is the light on, but nobody in?
I hope I have not come off sounding like that Said, I simply would like to see a great product better, I am hoping/committed to work with Agilent toward a better product if they are interested. And in the past I have found they are interested in our feedback. The 53132A was revolutionary in it's day, but with advances in time and freq there is now a market for a 14 or 15 digit counter. I am still attempting to individually characterize each item in my time and freq system and understand their strengths and weaknesses. And hope to learn more about the 53230A in the coming weeks. But TVB's comments in particular seemed consistent with my impressions so far. I would welcome your thoughts on the 53230A. Thanks;l Thomas Knox CC: time-nuts@febo.com From: saidj...@aol.com Date: Wed, 19 Feb 2014 08:25:28 -0800 To: time-nuts@febo.com Subject: Re: [time-nuts] strange behavior of 53230A or is the light on, but nobody in? Mike, They are already giving you another way to calibrate the unit, different from how you think they should have done it and you are pulling out the statist card and accusing them of being greedy capitalists? Come on, thats backseat driving. Be happy they invested millions of their own money and put out a more or less affordable new counter in a market flooded with good low-cost used counters. Bye, Said Sent From iPhone On Feb 19, 2014, at 0:33, mike cook michael.c...@sfr.fr wrote: Le 19 févr. 2014 à 01:05, Tom Knox a écrit : Thanks Tom and Bob, I have been thinking of contacting Agilent for some time. I think they are a great company with some good products, but there are a few real blind spots in some current products. I also have seen in the past a genuine interest in listening. I would be willing to approach them if I could enlist your help in addressing potential changes to improve the product. Thanks; Thomas Knox If they are steering the VCXXO,OCXO from the Ext. Ref. , then they are in effect calibrating it. Why not remember the applied EFC when they get phase lock? That can be applied when the internal timebase is selected. It couldn't be that they might lose the chance to sell a signal generator ;-), as calibration needs a square wave input, and the Ext. Ref In is ignored. From: li...@rtty.us Date: Tue, 18 Feb 2014 18:00:17 -0500 To: time-nuts@febo.com Subject: Re: [time-nuts] strange behavior of 53230A or is the light on, but nobody in? Hi Well at least this got me digging a little. If you grab a copy of the 53230A spec sheet and look under the external reference input, it’s pretty well described. It will accept 1, 5,10 MHz as an external reference. It will lock over a 1 ppm range with the XO option and 0.1 ppm with the OCXO option. Based on that I’d guess they are still using the same basic PLL approach as on the older counters (5335 era). The “Microsoft Windows inside” sticker on the back of the counter was a bit of a surprise …. No sticker on mine. Bob On Feb 18, 2014, at 11:51 AM, Tom Van Baak (lab) t...@leapsecond.com wrote: TomK, If anyone has technical contacts deep within Agilent, let's see if this issue can be resolved. I would have bought a 53230A when it came out a few years ago but my eval units showed this clock noise problem. That plus the poor quality of the ref out made me think the designers were cutting corners, or had little experience in metrology, or maybe they thought this was ok for a bench instrument. Otherwise it's a really nice counter; the first one from Agilent than can actually do ADEV properly (since it is a time stamping counter). I should dig out my old data and send it to you. Maybe as group we can help them fix the problem. /tvb On Feb 18, 2014, at 12:10 AM, Tom Knox act...@hotmail.com wrote: I have asked Agilent if stock versions of the 53230A and 53132A switched the internal oscillator out of circuit with an Ext Ref signal applied. I thought Agilent's engineer was intentionally vague but said the oscillators were indeed switched out of circuit on the counter with Ext Ref signal applied. These questions were related to several 53132A's I have seen configured with a small board back near the Ext Ref input (OPT H01 I think) that appeared to Switch the internal reference out of circuit. Agilent would not share information on the option. My question to Agilent is why sell an option and be unwilling to say what it does or how your stock unit functions? Thomas Knox From: t...@leapsecond.com Date: Mon, 17 Feb 2014 09:38:28 -1000 To: time-nuts@febo.com Subject: Re: [time-nuts] strange behavior of 53230A or is the light on,but nobody in? Bob, I'm wondering if you (or any else) has measured the PLL performance of the 53230-series? I agree it will
Re: [time-nuts] strange behavior of 53230A or is the light on, but nobody in?
Sorry early morning rant, There are counters out there already that can do 14/15 digits: tsc5125A and the Miles box for example. Very difficult to get a reference into that counter that can match and provide that type of stability. I am sure Agilent would love to hear our feedback probably as long as we don't accuse them of leaving out features purely as a profit motive. Heck Apple sells $160 production cost iPads for $800 and doesn't even include a calculator app for free. People don't care and they end up with $100+ billion cash in the bank. I'd rather have Agilent charge a bit more and have them still around 10 years from now. Bye, Said Sent From iPhone On Feb 19, 2014, at 10:08, Tom Knox act...@hotmail.com wrote: I hope I have not come off sounding like that Said, I simply would like to see a great product better, I am hoping/committed to work with Agilent toward a better product if they are interested. And in the past I have found they are interested in our feedback. The 53132A was revolutionary in it's day, but with advances in time and freq there is now a market for a 14 or 15 digit counter. I am still attempting to individually characterize each item in my time and freq system and understand their strengths and weaknesses. And hope to learn more about the 53230A in the coming weeks. But TVB's comments in particular seemed consistent with my impressions so far. I would welcome your thoughts on the 53230A. Thanks;l Thomas Knox CC: time-nuts@febo.com From: saidj...@aol.com Date: Wed, 19 Feb 2014 08:25:28 -0800 To: time-nuts@febo.com Subject: Re: [time-nuts] strange behavior of 53230A or is the light on, but nobody in? Mike, They are already giving you another way to calibrate the unit, different from how you think they should have done it and you are pulling out the statist card and accusing them of being greedy capitalists? Come on, thats backseat driving. Be happy they invested millions of their own money and put out a more or less affordable new counter in a market flooded with good low-cost used counters. Bye, Said Sent From iPhone On Feb 19, 2014, at 0:33, mike cook michael.c...@sfr.fr wrote: Le 19 févr. 2014 à 01:05, Tom Knox a écrit : Thanks Tom and Bob, I have been thinking of contacting Agilent for some time. I think they are a great company with some good products, but there are a few real blind spots in some current products. I also have seen in the past a genuine interest in listening. I would be willing to approach them if I could enlist your help in addressing potential changes to improve the product. Thanks; Thomas Knox If they are steering the VCXXO,OCXO from the Ext. Ref. , then they are in effect calibrating it. Why not remember the applied EFC when they get phase lock? That can be applied when the internal timebase is selected. It couldn't be that they might lose the chance to sell a signal generator ;-), as calibration needs a square wave input, and the Ext. Ref In is ignored. From: li...@rtty.us Date: Tue, 18 Feb 2014 18:00:17 -0500 To: time-nuts@febo.com Subject: Re: [time-nuts] strange behavior of 53230A or is the light on, but nobody in? Hi Well at least this got me digging a little. If you grab a copy of the 53230A spec sheet and look under the external reference input, it’s pretty well described. It will accept 1, 5,10 MHz as an external reference. It will lock over a 1 ppm range with the XO option and 0.1 ppm with the OCXO option. Based on that I’d guess they are still using the same basic PLL approach as on the older counters (5335 era). The “Microsoft Windows inside” sticker on the back of the counter was a bit of a surprise …. No sticker on mine. Bob On Feb 18, 2014, at 11:51 AM, Tom Van Baak (lab) t...@leapsecond.com wrote: TomK, If anyone has technical contacts deep within Agilent, let's see if this issue can be resolved. I would have bought a 53230A when it came out a few years ago but my eval units showed this clock noise problem. That plus the poor quality of the ref out made me think the designers were cutting corners, or had little experience in metrology, or maybe they thought this was ok for a bench instrument. Otherwise it's a really nice counter; the first one from Agilent than can actually do ADEV properly (since it is a time stamping counter). I should dig out my old data and send it to you. Maybe as group we can help them fix the problem. /tvb On Feb 18, 2014, at 12:10 AM, Tom Knox act...@hotmail.com wrote: I have asked Agilent if stock versions of the 53230A and 53132A switched the internal oscillator out of circuit with an Ext Ref signal applied. I thought Agilent's engineer was intentionally vague but said the oscillators were indeed switched out of circuit on the counter with Ext Ref signal applied. These questions were related to several
Re: [time-nuts] strange behavior of 53230A or is the light on, but nobody in?
On 2014-02-19 22:34, Said Jackson wrote: Sorry early morning rant, There are counters out there already that can do 14/15 digits: tsc5125A and the Miles box for example. Very difficult to get a reference into that counter that can match and provide that type of stability. I am sure Agilent would love to hear our feedback probably as long as we don't accuse them of leaving out features purely as a profit motive. Heck Apple sells $160 production cost iPads for $800 and doesn't even include a calculator app for free. People don't care and they end up with $100+ billion cash in the bank. I'd rather have Agilent charge a bit more and have them still around 10 years from now. They won't be, not under that name at least. Unfortunatly they ended up with another name which will be hard to remember. Cheers, Magnus ___ 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] strange behavior of 53230A or is the light on, but nobody in?
I have asked Agilent if stock versions of the 53230A and 53132A switched the internal oscillator out of circuit with an Ext Ref signal applied. I thought Agilent's engineer was intentionally vague but said the oscillators were indeed switched out of circuit on the counter with Ext Ref signal applied. These questions were related to several 53132A's I have seen configured with a small board back near the Ext Ref input (OPT H01 I think) that appeared to Switch the internal reference out of circuit. Agilent would not share information on the option. My question to Agilent is why sell an option and be unwilling to say what it does or how your stock unit functions? Thomas Knox From: t...@leapsecond.com Date: Mon, 17 Feb 2014 09:38:28 -1000 To: time-nuts@febo.com Subject: Re: [time-nuts] strange behavior of 53230A or is the light on, but nobody in? Bob, I'm wondering if you (or any else) has measured the PLL performance of the 53230-series? I agree it will clean up the crud but this assumes the ext ref is dirtier than the internal osc. What I found instead was that if you use a good external ref the PLL actually makes it worse. This was very disappointing. The XO version of the counter performed worse than the OCXO version even with a maser as the ext reference. Did your reading of the schematic show a way to directly use the ext ref, bypassing the noisy PLL? The other thing I found was that the ref out signal was a very polluted copy of the ref in. /tvb (i5s) On Feb 17, 2014, at 7:04 AM, Bob Camp li...@rtty.us wrote: Hi If you dig into the schematics (when they supplied them … ): The external reference goes into a phase detector. It’s one of those digital ones that can lock up to many inputs. You could feed 3. MHz in as a standard input as well as 0.5, 1, 2.5, 5, and 10 MHz. The internal oscillator (or an internal oscillator) is phase locked to the external input through a fairly narrow analog loop. The idea is to clean up the crud on the standard line. With no external reference, the PLL drops out and you go back to what ever the local reference is. Yes there’s a little more to it than that and no the circuit is not exactly the same on every counter HP ever made. Bob On Feb 17, 2014, at 7:55 AM, wb6bnq wb6...@cox.net wrote: Hi Mike, The most likely answer is when you select external time base for an input, it disables the connection for the internal oscillator. The external input signal is probably also routed straight to the reference output jack. However, it would be good to read the manual, as they usually cover how those connections work. Otherwise, perhaps someone that owns one could provide further insight. BillWB6BNQ mike cook wrote: Something that must be simple to explain, but that I can't get my head round. I got a new 53230A. When first using it, I measured my T-Bolt 10MHz using the internal 10MHz timebase and it came up short of 10MHz, 9.999 998 5xx. I wasn't worried about it as the counter only has a TCXO internal oscillator. So I fired up my PRS10 and after leaving that on for some time, connected it to Ext Ref. , changed to the ext time base and measured again. This time 10.000.000.00x. Then I switched the two references, measuring the PRS10 against the T-Bolt. Again I got 10MHz down to the 11th digit. All that looked good so I have been using it with either the PRS10 locked to GPS, or the T-Bolt as the external time base. After leaving it on (but not inactive) for a month, I did an Autocal. No problem. I was wondering if that would have changed the internal time base frequency, but no, using that still gave similar figures to the above. So at that point I decided to measure the Internal TB against my reference. So I connected the Int. Ref. Out to channel 1, connected my PRS10 ref to Ext. Ref In, selected the EXT time base and found that the count was 10MHz dead on? I don't get that at all. in summary: DUT against internal TB counts 10MHz.To me that means that the internal timebase is a bit fast. Is that assumption correct? DUT against Ext.Ref counts 10MHz Internal TB against Ext.Ref counts 10MHz. If my assumption above is correct, the count should be greater than 10MHz, no? Can anyone shed any light on that? ___ 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] strange behavior of 53230A or is the light on, but nobody in?
TomK, If anyone has technical contacts deep within Agilent, let's see if this issue can be resolved. I would have bought a 53230A when it came out a few years ago but my eval units showed this clock noise problem. That plus the poor quality of the ref out made me think the designers were cutting corners, or had little experience in metrology, or maybe they thought this was ok for a bench instrument. Otherwise it's a really nice counter; the first one from Agilent than can actually do ADEV properly (since it is a time stamping counter). I should dig out my old data and send it to you. Maybe as group we can help them fix the problem. /tvb On Feb 18, 2014, at 12:10 AM, Tom Knox act...@hotmail.com wrote: I have asked Agilent if stock versions of the 53230A and 53132A switched the internal oscillator out of circuit with an Ext Ref signal applied. I thought Agilent's engineer was intentionally vague but said the oscillators were indeed switched out of circuit on the counter with Ext Ref signal applied. These questions were related to several 53132A's I have seen configured with a small board back near the Ext Ref input (OPT H01 I think) that appeared to Switch the internal reference out of circuit. Agilent would not share information on the option. My question to Agilent is why sell an option and be unwilling to say what it does or how your stock unit functions? Thomas Knox From: t...@leapsecond.com Date: Mon, 17 Feb 2014 09:38:28 -1000 To: time-nuts@febo.com Subject: Re: [time-nuts] strange behavior of 53230A or is the light on, but nobody in? Bob, I'm wondering if you (or any else) has measured the PLL performance of the 53230-series? I agree it will clean up the crud but this assumes the ext ref is dirtier than the internal osc. What I found instead was that if you use a good external ref the PLL actually makes it worse. This was very disappointing. The XO version of the counter performed worse than the OCXO version even with a maser as the ext reference. Did your reading of the schematic show a way to directly use the ext ref, bypassing the noisy PLL? The other thing I found was that the ref out signal was a very polluted copy of the ref in. /tvb (i5s) On Feb 17, 2014, at 7:04 AM, Bob Camp li...@rtty.us wrote: Hi If you dig into the schematics (when they supplied them … ): The external reference goes into a phase detector. It’s one of those digital ones that can lock up to many inputs. You could feed 3. MHz in as a standard input as well as 0.5, 1, 2.5, 5, and 10 MHz. The internal oscillator (or an internal oscillator) is phase locked to the external input through a fairly narrow analog loop. The idea is to clean up the crud on the standard line. With no external reference, the PLL drops out and you go back to what ever the local reference is. Yes there’s a little more to it than that and no the circuit is not exactly the same on every counter HP ever made. Bob On Feb 17, 2014, at 7:55 AM, wb6bnq wb6...@cox.net wrote: Hi Mike, The most likely answer is when you select external time base for an input, it disables the connection for the internal oscillator. The external input signal is probably also routed straight to the reference output jack. However, it would be good to read the manual, as they usually cover how those connections work. Otherwise, perhaps someone that owns one could provide further insight. BillWB6BNQ mike cook wrote: Something that must be simple to explain, but that I can't get my head round. I got a new 53230A. When first using it, I measured my T-Bolt 10MHz using the internal 10MHz timebase and it came up short of 10MHz, 9.999 998 5xx. I wasn't worried about it as the counter only has a TCXO internal oscillator. So I fired up my PRS10 and after leaving that on for some time, connected it to Ext Ref. , changed to the ext time base and measured again. This time 10.000.000.00x. Then I switched the two references, measuring the PRS10 against the T-Bolt. Again I got 10MHz down to the 11th digit. All that looked good so I have been using it with either the PRS10 locked to GPS, or the T-Bolt as the external time base. After leaving it on (but not inactive) for a month, I did an Autocal. No problem. I was wondering if that would have changed the internal time base frequency, but no, using that still gave similar figures to the above. So at that point I decided to measure the Internal TB against my reference. So I connected the Int. Ref. Out to channel 1, connected my PRS10 ref to Ext. Ref In, selected the EXT time base and found that the count was 10MHz dead on? I don't get that at all. in summary: DUT against internal TB counts 10MHz.To me that means that the internal timebase is a bit fast. Is that assumption correct? DUT against Ext.Ref counts 10MHz Internal TB against
Re: [time-nuts] strange behavior of 53230A or is the light on, but nobody in?
Hi Well at least this got me digging a little. If you grab a copy of the 53230A spec sheet and look under the external reference input, it’s pretty well described. It will accept 1, 5,10 MHz as an external reference. It will lock over a 1 ppm range with the XO option and 0.1 ppm with the OCXO option. Based on that I’d guess they are still using the same basic PLL approach as on the older counters (5335 era). The “Microsoft Windows inside” sticker on the back of the counter was a bit of a surprise …. Bob On Feb 18, 2014, at 11:51 AM, Tom Van Baak (lab) t...@leapsecond.com wrote: TomK, If anyone has technical contacts deep within Agilent, let's see if this issue can be resolved. I would have bought a 53230A when it came out a few years ago but my eval units showed this clock noise problem. That plus the poor quality of the ref out made me think the designers were cutting corners, or had little experience in metrology, or maybe they thought this was ok for a bench instrument. Otherwise it's a really nice counter; the first one from Agilent than can actually do ADEV properly (since it is a time stamping counter). I should dig out my old data and send it to you. Maybe as group we can help them fix the problem. /tvb On Feb 18, 2014, at 12:10 AM, Tom Knox act...@hotmail.com wrote: I have asked Agilent if stock versions of the 53230A and 53132A switched the internal oscillator out of circuit with an Ext Ref signal applied. I thought Agilent's engineer was intentionally vague but said the oscillators were indeed switched out of circuit on the counter with Ext Ref signal applied. These questions were related to several 53132A's I have seen configured with a small board back near the Ext Ref input (OPT H01 I think) that appeared to Switch the internal reference out of circuit. Agilent would not share information on the option. My question to Agilent is why sell an option and be unwilling to say what it does or how your stock unit functions? Thomas Knox From: t...@leapsecond.com Date: Mon, 17 Feb 2014 09:38:28 -1000 To: time-nuts@febo.com Subject: Re: [time-nuts] strange behavior of 53230A or is the light on, but nobody in? Bob, I'm wondering if you (or any else) has measured the PLL performance of the 53230-series? I agree it will clean up the crud but this assumes the ext ref is dirtier than the internal osc. What I found instead was that if you use a good external ref the PLL actually makes it worse. This was very disappointing. The XO version of the counter performed worse than the OCXO version even with a maser as the ext reference. Did your reading of the schematic show a way to directly use the ext ref, bypassing the noisy PLL? The other thing I found was that the ref out signal was a very polluted copy of the ref in. /tvb (i5s) On Feb 17, 2014, at 7:04 AM, Bob Camp li...@rtty.us wrote: Hi If you dig into the schematics (when they supplied them … ): The external reference goes into a phase detector. It’s one of those digital ones that can lock up to many inputs. You could feed 3. MHz in as a standard input as well as 0.5, 1, 2.5, 5, and 10 MHz. The internal oscillator (or an internal oscillator) is phase locked to the external input through a fairly narrow analog loop. The idea is to clean up the crud on the standard line. With no external reference, the PLL drops out and you go back to what ever the local reference is. Yes there’s a little more to it than that and no the circuit is not exactly the same on every counter HP ever made. Bob On Feb 17, 2014, at 7:55 AM, wb6bnq wb6...@cox.net wrote: Hi Mike, The most likely answer is when you select external time base for an input, it disables the connection for the internal oscillator. The external input signal is probably also routed straight to the reference output jack. However, it would be good to read the manual, as they usually cover how those connections work. Otherwise, perhaps someone that owns one could provide further insight. BillWB6BNQ mike cook wrote: Something that must be simple to explain, but that I can't get my head round. I got a new 53230A. When first using it, I measured my T-Bolt 10MHz using the internal 10MHz timebase and it came up short of 10MHz, 9.999 998 5xx. I wasn't worried about it as the counter only has a TCXO internal oscillator. So I fired up my PRS10 and after leaving that on for some time, connected it to Ext Ref. , changed to the ext time base and measured again. This time 10.000.000.00x. Then I switched the two references, measuring the PRS10 against the T-Bolt. Again I got 10MHz down to the 11th digit. All that looked good so I have been using it with either the PRS10 locked to GPS, or the T-Bolt as the external time base. After leaving it on (but not inactive) for a month, I did an Autocal. No problem. I
Re: [time-nuts] strange behavior of 53230A or is the light on, but nobody in?
Thanks Tom and Bob, I have been thinking of contacting Agilent for some time. I think they are a great company with some good products, but there are a few real blind spots in some current products. I also have seen in the past a genuine interest in listening. I would be willing to approach them if I could enlist your help in addressing potential changes to improve the product. Thanks; Thomas Knox From: li...@rtty.us Date: Tue, 18 Feb 2014 18:00:17 -0500 To: time-nuts@febo.com Subject: Re: [time-nuts] strange behavior of 53230A or is the light on, but nobody in? Hi Well at least this got me digging a little. If you grab a copy of the 53230A spec sheet and look under the external reference input, it’s pretty well described. It will accept 1, 5,10 MHz as an external reference. It will lock over a 1 ppm range with the XO option and 0.1 ppm with the OCXO option. Based on that I’d guess they are still using the same basic PLL approach as on the older counters (5335 era). The “Microsoft Windows inside” sticker on the back of the counter was a bit of a surprise …. Bob On Feb 18, 2014, at 11:51 AM, Tom Van Baak (lab) t...@leapsecond.com wrote: TomK, If anyone has technical contacts deep within Agilent, let's see if this issue can be resolved. I would have bought a 53230A when it came out a few years ago but my eval units showed this clock noise problem. That plus the poor quality of the ref out made me think the designers were cutting corners, or had little experience in metrology, or maybe they thought this was ok for a bench instrument. Otherwise it's a really nice counter; the first one from Agilent than can actually do ADEV properly (since it is a time stamping counter). I should dig out my old data and send it to you. Maybe as group we can help them fix the problem. /tvb On Feb 18, 2014, at 12:10 AM, Tom Knox act...@hotmail.com wrote: I have asked Agilent if stock versions of the 53230A and 53132A switched the internal oscillator out of circuit with an Ext Ref signal applied. I thought Agilent's engineer was intentionally vague but said the oscillators were indeed switched out of circuit on the counter with Ext Ref signal applied. These questions were related to several 53132A's I have seen configured with a small board back near the Ext Ref input (OPT H01 I think) that appeared to Switch the internal reference out of circuit. Agilent would not share information on the option. My question to Agilent is why sell an option and be unwilling to say what it does or how your stock unit functions? Thomas Knox From: t...@leapsecond.com Date: Mon, 17 Feb 2014 09:38:28 -1000 To: time-nuts@febo.com Subject: Re: [time-nuts] strange behavior of 53230A or is the light on, but nobody in? Bob, I'm wondering if you (or any else) has measured the PLL performance of the 53230-series? I agree it will clean up the crud but this assumes the ext ref is dirtier than the internal osc. What I found instead was that if you use a good external ref the PLL actually makes it worse. This was very disappointing. The XO version of the counter performed worse than the OCXO version even with a maser as the ext reference. Did your reading of the schematic show a way to directly use the ext ref, bypassing the noisy PLL? The other thing I found was that the ref out signal was a very polluted copy of the ref in. /tvb (i5s) On Feb 17, 2014, at 7:04 AM, Bob Camp li...@rtty.us wrote: Hi If you dig into the schematics (when they supplied them … ): The external reference goes into a phase detector. It’s one of those digital ones that can lock up to many inputs. You could feed 3. MHz in as a standard input as well as 0.5, 1, 2.5, 5, and 10 MHz. The internal oscillator (or an internal oscillator) is phase locked to the external input through a fairly narrow analog loop. The idea is to clean up the crud on the standard line. With no external reference, the PLL drops out and you go back to what ever the local reference is. Yes there’s a little more to it than that and no the circuit is not exactly the same on every counter HP ever made. Bob On Feb 17, 2014, at 7:55 AM, wb6bnq wb6...@cox.net wrote: Hi Mike, The most likely answer is when you select external time base for an input, it disables the connection for the internal oscillator. The external input signal is probably also routed straight to the reference output jack. However, it would be good to read the manual, as they usually cover how those connections work. Otherwise, perhaps someone that owns one could provide further insight. BillWB6BNQ mike cook wrote: Something that must be simple to explain, but that I can't get my head round. I got a new 53230A. When
Re: [time-nuts] strange behavior of 53230A or is the light on, but nobody in?
Did you disconnect the external reference from the 53230A before doing the test? If no, I'll bet that the external reference being connected overrides the internal reference Regards, David Partridge ___ 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] strange behavior of 53230A or is the light on, but nobody in?
Le 17 févr. 2014 à 13:49, gandal...@aol.com a écrit : Hi Michael Internal reference out is likely to be of the actual reference in use, ie with an external reference connected that's what will be on the output connector and would explain what you're seeing. Your initial test, using the T'bolt and internal reference should be giving you the accurate measure of the internal reference. Thanks guys. That would explain it, but there is nothing I can see in the doc which confirms it. I will see if I have a 5MHz or 1MHz oscillator that I could use to check that. Regards Nigel GM8PZR ___ 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] strange behavior of 53230A or is the light on, but nobody in?
Hi It locks up the internal reference to the external reference when the external reference is present. It’s the same behavior as the 5334,5335,5345,5360,5370,5318x,and 5313x. Bob On Feb 17, 2014, at 8:31 AM, mike cook michael.c...@sfr.fr wrote: Le 17 févr. 2014 à 13:49, gandal...@aol.com a écrit : Hi Michael Internal reference out is likely to be of the actual reference in use, ie with an external reference connected that's what will be on the output connector and would explain what you're seeing. Your initial test, using the T'bolt and internal reference should be giving you the accurate measure of the internal reference. Thanks guys. That would explain it, but there is nothing I can see in the doc which confirms it. I will see if I have a 5MHz or 1MHz oscillator that I could use to check that. Regards Nigel GM8PZR ___ 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] strange behavior of 53230A or is the light on, but nobody in?
In message ff58a3fc-3e6a-4b13-83e3-c1363a556...@sfr.fr, mike cook writes: So at that point I decided to measure the Internal TB against my reference. So I connected the Int. Ref. Out to channel 1, connected my PRS10 ref to Ext. Ref In, selected the EXT time base and found that the count was 10MHz dead on? I don't get that at all. On all the HP kit I have, ref out is the frequency used by the instrument, so if you feed it an external reference, it is just a copy of that external reference. -- Poul-Henning Kamp | UNIX since Zilog Zeus 3.20 p...@freebsd.org | TCP/IP since RFC 956 FreeBSD committer | BSD since 4.3-tahoe Never attribute to malice what can adequately be explained by incompetence. ___ 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] strange behavior of 53230A or is the light on, but nobody in?
Hi Mike, The most likely answer is when you select external time base for an input, it disables the connection for the internal oscillator. The external input signal is probably also routed straight to the reference output jack. However, it would be good to read the manual, as they usually cover how those connections work. Otherwise, perhaps someone that owns one could provide further insight. BillWB6BNQ mike cook wrote: Something that must be simple to explain, but that I can't get my head round. I got a new 53230A. When first using it, I measured my T-Bolt 10MHz using the internal 10MHz timebase and it came up short of 10MHz, 9.999 998 5xx. I wasn't worried about it as the counter only has a TCXO internal oscillator. So I fired up my PRS10 and after leaving that on for some time, connected it to Ext Ref. , changed to the ext time base and measured again. This time 10.000.000.00x. Then I switched the two references, measuring the PRS10 against the T-Bolt. Again I got 10MHz down to the 11th digit. All that looked good so I have been using it with either the PRS10 locked to GPS, or the T-Bolt as the external time base. After leaving it on (but not inactive) for a month, I did an Autocal. No problem. I was wondering if that would have changed the internal time base frequency, but no, using that still gave similar figures to the above. So at that point I decided to measure the Internal TB against my reference. So I connected the Int. Ref. Out to channel 1, connected my PRS10 ref to Ext. Ref In, selected the EXT time base and found that the count was 10MHz dead on? I don't get that at all. in summary: DUT against internal TB counts 10MHz.To me that means that the internal timebase is a bit fast. Is that assumption correct? DUT against Ext.Ref counts 10MHz Internal TB against Ext.Ref counts 10MHz. If my assumption above is correct, the count should be greater than 10MHz, no? Can anyone shed any light on that? ___ 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] strange behavior of 53230A or is the light on, but nobody in?
Hi If you dig into the schematics (when they supplied them … ): The external reference goes into a phase detector. It’s one of those digital ones that can lock up to many inputs. You could feed 3. MHz in as a standard input as well as 0.5, 1, 2.5, 5, and 10 MHz. The internal oscillator (or an internal oscillator) is phase locked to the external input through a fairly narrow analog loop. The idea is to clean up the crud on the standard line. With no external reference, the PLL drops out and you go back to what ever the local reference is. Yes there’s a little more to it than that and no the circuit is not exactly the same on every counter HP ever made. Bob On Feb 17, 2014, at 7:55 AM, wb6bnq wb6...@cox.net wrote: Hi Mike, The most likely answer is when you select external time base for an input, it disables the connection for the internal oscillator. The external input signal is probably also routed straight to the reference output jack. However, it would be good to read the manual, as they usually cover how those connections work. Otherwise, perhaps someone that owns one could provide further insight. BillWB6BNQ mike cook wrote: Something that must be simple to explain, but that I can't get my head round. I got a new 53230A. When first using it, I measured my T-Bolt 10MHz using the internal 10MHz timebase and it came up short of 10MHz, 9.999 998 5xx. I wasn't worried about it as the counter only has a TCXO internal oscillator. So I fired up my PRS10 and after leaving that on for some time, connected it to Ext Ref. , changed to the ext time base and measured again. This time 10.000.000.00x. Then I switched the two references, measuring the PRS10 against the T-Bolt. Again I got 10MHz down to the 11th digit. All that looked good so I have been using it with either the PRS10 locked to GPS, or the T-Bolt as the external time base. After leaving it on (but not inactive) for a month, I did an Autocal. No problem. I was wondering if that would have changed the internal time base frequency, but no, using that still gave similar figures to the above. So at that point I decided to measure the Internal TB against my reference. So I connected the Int. Ref. Out to channel 1, connected my PRS10 ref to Ext. Ref In, selected the EXT time base and found that the count was 10MHz dead on? I don't get that at all. in summary: DUT against internal TB counts 10MHz.To me that means that the internal timebase is a bit fast. Is that assumption correct? DUT against Ext.Ref counts 10MHz Internal TB against Ext.Ref counts 10MHz. If my assumption above is correct, the count should be greater than 10MHz, no? Can anyone shed any light on that? ___ 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] strange behavior of 53230A or is the light on, but nobody in?
Bob, I'm wondering if you (or any else) has measured the PLL performance of the 53230-series? I agree it will clean up the crud but this assumes the ext ref is dirtier than the internal osc. What I found instead was that if you use a good external ref the PLL actually makes it worse. This was very disappointing. The XO version of the counter performed worse than the OCXO version even with a maser as the ext reference. Did your reading of the schematic show a way to directly use the ext ref, bypassing the noisy PLL? The other thing I found was that the ref out signal was a very polluted copy of the ref in. /tvb (i5s) On Feb 17, 2014, at 7:04 AM, Bob Camp li...@rtty.us wrote: Hi If you dig into the schematics (when they supplied them … ): The external reference goes into a phase detector. It’s one of those digital ones that can lock up to many inputs. You could feed 3. MHz in as a standard input as well as 0.5, 1, 2.5, 5, and 10 MHz. The internal oscillator (or an internal oscillator) is phase locked to the external input through a fairly narrow analog loop. The idea is to clean up the crud on the standard line. With no external reference, the PLL drops out and you go back to what ever the local reference is. Yes there’s a little more to it than that and no the circuit is not exactly the same on every counter HP ever made. Bob On Feb 17, 2014, at 7:55 AM, wb6bnq wb6...@cox.net wrote: Hi Mike, The most likely answer is when you select external time base for an input, it disables the connection for the internal oscillator. The external input signal is probably also routed straight to the reference output jack. However, it would be good to read the manual, as they usually cover how those connections work. Otherwise, perhaps someone that owns one could provide further insight. BillWB6BNQ mike cook wrote: Something that must be simple to explain, but that I can't get my head round. I got a new 53230A. When first using it, I measured my T-Bolt 10MHz using the internal 10MHz timebase and it came up short of 10MHz, 9.999 998 5xx. I wasn't worried about it as the counter only has a TCXO internal oscillator. So I fired up my PRS10 and after leaving that on for some time, connected it to Ext Ref. , changed to the ext time base and measured again. This time 10.000.000.00x. Then I switched the two references, measuring the PRS10 against the T-Bolt. Again I got 10MHz down to the 11th digit. All that looked good so I have been using it with either the PRS10 locked to GPS, or the T-Bolt as the external time base. After leaving it on (but not inactive) for a month, I did an Autocal. No problem. I was wondering if that would have changed the internal time base frequency, but no, using that still gave similar figures to the above. So at that point I decided to measure the Internal TB against my reference. So I connected the Int. Ref. Out to channel 1, connected my PRS10 ref to Ext. Ref In, selected the EXT time base and found that the count was 10MHz dead on? I don't get that at all. in summary: DUT against internal TB counts 10MHz.To me that means that the internal timebase is a bit fast. Is that assumption correct? DUT against Ext.Ref counts 10MHz Internal TB against Ext.Ref counts 10MHz. If my assumption above is correct, the count should be greater than 10MHz, no? Can anyone shed any light on that? ___ 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] strange behavior of 53230A or is the light on, but nobody in?
Hi I have a 53230, but have not gotten around to looking at it’s PLL cleanup process. Bob On Feb 17, 2014, at 2:38 PM, Tom Van Baak (lab) t...@leapsecond.com wrote: Bob, I'm wondering if you (or any else) has measured the PLL performance of the 53230-series? I agree it will clean up the crud but this assumes the ext ref is dirtier than the internal osc. What I found instead was that if you use a good external ref the PLL actually makes it worse. This was very disappointing. The XO version of the counter performed worse than the OCXO version even with a maser as the ext reference. Did your reading of the schematic show a way to directly use the ext ref, bypassing the noisy PLL? The other thing I found was that the ref out signal was a very polluted copy of the ref in. /tvb (i5s) On Feb 17, 2014, at 7:04 AM, Bob Camp li...@rtty.us wrote: Hi If you dig into the schematics (when they supplied them … ): The external reference goes into a phase detector. It’s one of those digital ones that can lock up to many inputs. You could feed 3. MHz in as a standard input as well as 0.5, 1, 2.5, 5, and 10 MHz. The internal oscillator (or an internal oscillator) is phase locked to the external input through a fairly narrow analog loop. The idea is to clean up the crud on the standard line. With no external reference, the PLL drops out and you go back to what ever the local reference is. Yes there’s a little more to it than that and no the circuit is not exactly the same on every counter HP ever made. Bob On Feb 17, 2014, at 7:55 AM, wb6bnq wb6...@cox.net wrote: Hi Mike, The most likely answer is when you select external time base for an input, it disables the connection for the internal oscillator. The external input signal is probably also routed straight to the reference output jack. However, it would be good to read the manual, as they usually cover how those connections work. Otherwise, perhaps someone that owns one could provide further insight. BillWB6BNQ mike cook wrote: Something that must be simple to explain, but that I can't get my head round. I got a new 53230A. When first using it, I measured my T-Bolt 10MHz using the internal 10MHz timebase and it came up short of 10MHz, 9.999 998 5xx. I wasn't worried about it as the counter only has a TCXO internal oscillator. So I fired up my PRS10 and after leaving that on for some time, connected it to Ext Ref. , changed to the ext time base and measured again. This time 10.000.000.00x. Then I switched the two references, measuring the PRS10 against the T-Bolt. Again I got 10MHz down to the 11th digit. All that looked good so I have been using it with either the PRS10 locked to GPS, or the T-Bolt as the external time base. After leaving it on (but not inactive) for a month, I did an Autocal. No problem. I was wondering if that would have changed the internal time base frequency, but no, using that still gave similar figures to the above. So at that point I decided to measure the Internal TB against my reference. So I connected the Int. Ref. Out to channel 1, connected my PRS10 ref to Ext. Ref In, selected the EXT time base and found that the count was 10MHz dead on? I don't get that at all. in summary: DUT against internal TB counts 10MHz.To me that means that the internal timebase is a bit fast. Is that assumption correct? DUT against Ext.Ref counts 10MHz Internal TB against Ext.Ref counts 10MHz. If my assumption above is correct, the count should be greater than 10MHz, no? Can anyone shed any light on that? ___ 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.
