Re: [time-nuts] DDS in GPSDO design?

-Original Message- From: time-nuts-boun...@febo.com [mailto:time-nuts-boun...@febo.com] On Behalf Of Bruce Griffiths Sent: Monday, May 28, 2012 12:10 AM To: Discussion of precise time and frequency measurement Subject: Re: [time-nuts] DDS in GPSDO design? Michael Tharp wrote: On 05/27/2012 06

Re: [time-nuts] DDS in GPSDO design?

Message- From: time-nuts-boun...@febo.com [mailto:time-nuts-boun...@febo.com] On Behalf Of Bruce Griffiths Sent: Monday, May 28, 2012 12:10 AM To: Discussion of precise time and frequency measurement Subject: Re: [time-nuts] DDS in GPSDO design? Michael Tharp wrote: On 05/27/2012 06:23 PM

Re: [time-nuts] DDS in GPSDO design?

Michael Tharp wrote: On 05/27/2012 06:23 PM, Bruce Griffiths wrote: The principal problem with conventional DDS implementations is phase truncation spurs which can occur close to the desired carrier. Virtually all commercial DDS chips produce such phase truncation spurs. It is possible to

Re: [time-nuts] DDS in GPSDO design?

The keyword is good most commercial DDS chips aren't (at least when used directly for a fine offset generator ). The Symmetricom TSC5120A phase noise test set implements the DDS in an FPGA wherein which its possible to virtually avoid the phase truncation errors produced by commercial DDS chips.

Re: [time-nuts] DDS in GPSDO design?

Michael Tharp wrote: Greetings, I've been pondering topologies for a custom GPSDO design and two obvious choices seem to present themselves. The first, and seemingly more popular by far, is to use a "pullable" oscillator as many OCXO and Rb oscillators are and discipline it using a slow but p

Re: [time-nuts] NTGS50AA, better than Thunderbolt

One of my 37265's has a phase noise floor of -174dBc/Hz (measured using the dual (statistically independent) reference technique). My pair of 34310-T's appear to have a phase noise floor of around -150dBc/Hz. Bruce Mark Sims wrote: Yes. I once read that the 37265 was a double oven unit,

Re: [time-nuts] NTGS50AA, better than Thunderbolt

Mark Sims wrote: It appears to be the same as the other one (which has an unreadable label). This one is marked Trimble 0001-262T 34310-T2. So far it appears to be oblivious to external temperature changes. I don't know about its phase noise. The other unit had been running 24/7 for sever

Re: [time-nuts] NTGS50AA, better than Thunderbolt

John Miles wrote: While I've not tried the recently suggested method for making it talk to LH, I did find another crude way that works. If you get it talking to TBOLTMON or some similar software via the front panel, you can use LH on another computer on the rear-panel monitor port to

Re: [time-nuts] Wilkinson TDC

David wrote: On Mon, 30 Apr 2012 06:51:37 +1200, Bruce Griffiths wrote: The circuit for the Tek 2440 is in the manual. However, it isnt that well executed. I like using the 2440 as an example because the design and theory are readily available online. Its execution only had to be

Re: [time-nuts] Wilkinson TDC

: Do you have an actual circuit? It looks a lot like the old hp5360 counter interpolator. Regards Paul On Sun, Apr 29, 2012 at 3:51 AM, Bruce Griffiths wrote: The essentials of a Wikinson TDC can be simplified to the attached circuit which only requires the addition of a zero

[time-nuts] Wilkinson TDC

The essentials of a Wikinson TDC can be simplified to the attached circuit which only requires the addition of a zero crossing comparator to monitor the voltage across the capacitor C1. A few refinements to improve the capacitor charging current switching transitions and the addition of an upp

Re: [time-nuts] PICTIC II ready-made?

Yes, I should have been more specific. The details about the state machine clock behaviour aren't on the datasheet and were obtained by asking Xilinx. The reason for using CMOS RAM to controll the CPLD interconnections is to reduce the static power consumption well below that possible when usin

Re: [time-nuts] PICTIC II ready-made?

ou have no clock at all: there is no configuration to load. On Fri, Apr 27, 2012 at 10:01 PM, Bruce Griffiths< bruce.griffi...@xtra.co.nz> wrote: The Wilkinson TDC (dual slope) has been successfully used for decades in nuclear instrumentation. One problem is in switching the discharg

Re: [time-nuts] PICTIC II ready-made?

The Wilkinson TDC (dual slope) has been successfully used for decades in nuclear instrumentation. One problem is in switching the discharge current on and off sufficiently quickly. This can be largely circumvented by having it on all the time. One drawback is the slow conversion speed (100us for

Re: [time-nuts] PICTIC II ready-made?

Attila Kinali wrote: Hi Bruce, On Thu, 26 Apr 2012 07:15:41 +1200 Bruce Griffiths wrote: If a suitable ADC is used the interpolator can be simplified considerably whilst improving its performance. Could you tell a little bit more about what a "suitable ADC" for a time in

Re: [time-nuts] PICTIC II ready-made?

Chris Albertson wrote: On Wed, Apr 25, 2012 at 9:37 AM, Don Latham wrote: I forgot to add that a simple redrafting of the II as an Arduino shield with appropriate chips and chip passives would accomplish the desired end without losing the very careful engineering and testing that has alrea

Re: [time-nuts] Question about precise frequency / phase measurement

Attila Kinali wrote: On Thu, 19 Apr 2012 23:39:32 +0200 skywatcher wrote: BTW i'm using the Parallax 'Propeller' controller which has 8 cores running at 80 MHz each, and can measure time intervals with 12.5 ns resolution. [...] Looks like an interesting thing. But also very specia

Re: [time-nuts] Question about precise frequency / phase measurement

Use a dual mixer system with an offset LO. Bruce Azelio Boriani wrote: And, if you are measuring, by analog mixing, two very slightly different frequencies, what do you expect to obtain if not a signal that is slow, very slow. How can you measure milliHertz or microHertz without waiting? On Th

Re: [time-nuts] Question about precise frequency / phase measurement

Using a dual mixer time difference system (either the digital dual mixer time difference (DDMTD) or the analog variant (DMTD)) can easily achieve the required resolution. The DDMTD is relatively cheap to implement however it requires an offset oscillator to beat against the 2 signals being compa

Re: [time-nuts] Opamp Phase noise: OPA653 additional measurements

i My *guess* is that your 1Hz data may be as much from ambient changes as from the op amps themselves. No data to back that up on these specific parts, just a guess. Bob On Apr 17, 2012, at 7:28 AM, Bruce Griffiths wrote: Not yet, I just used the pair of TI evaluation boards which I obtaine

Re: [time-nuts] Opamp Phase noise: OPA653 additional measurements

you do any temperature stabilization on the op amps? Bob On Apr 17, 2012, at 5:25 AM, Bruce Griffiths wrote: Subsequent measurements using an improved technique has allowed the true flicker phase noise characteristics of a pair of OPA653 opamps to be determined. Opamp Gain 1x (6db

Re: [time-nuts] Opamp Phase noise: OPA653 additional measurements

Boriani wrote: Very good. I'm fascinated by the figures... how can such phase noise levels be measured and, in general, being able to "sense" the most faint signal. On Tue, Apr 17, 2012 at 11:25 AM, Bruce Griffiths< bruce.griffi...@xtra.co.nz> wrote: Subsequent measureme

[time-nuts] Opamp Phase noise: OPA653 additional measurements

Subsequent measurements using an improved technique has allowed the true flicker phase noise characteristics of a pair of OPA653 opamps to be determined. Opamp Gain 1x (6db folled by 6 db attenuator consisting of a 50 ohm resistor in series with the output of the opamp and the 50 ohm load

Re: [time-nuts] Distribution amp - Use a video amp unit ?

The LMH6702 is one of the few current feedback amplifiers that is stable with a relatively low value (237 ohm) feedback resistor. Its estimated phase noise floor is around -171 dBc/Hz with +13dBm output (and input) in the noninverting 2x configuration with a 50 ohm load and a 50 ohm resistor i

Re: [time-nuts] Distribution amp - Use a video amp unit ?

Charles P. Steinmetz wrote: Bruce wrote: A circuit schematic for a current feedback triple with reasonably low noise and distortion is attached. Quite a good performer for such a simple circuit. I found, both in modeling and on the bench, that there is the usual noise bump at 200-300 MHz a

Re: [time-nuts] Distribution amp - Use a video amp unit ?

cfo wrote: On Mon, 26 Mar 2012 08:11:16 +1300, Bruce Griffiths wrote: Bruce Griffiths wrote: A circuit schematic for a current feedback triple with reasonably low noise and distortion is attached. Bruce Thanx Bruce I'm an analog noob , so i have some questions.

Re: [time-nuts] Distribution amp - Use a video amp unit ?

Charles P. Steinmetz wrote: Bruce wrote: A circuit schematic for a current feedback triple with reasonably low noise and distortion is attached. One caution regarding the 100 uH inductor (L3) -- many inductors of this value exhibit self-resonance below 10 MHz, so some care may be necessary

Re: [time-nuts] Distribution amp - Use a video amp unit ?

cfo wrote: I need a distribution amp for my Tbolt , with 6..8+ outputs The TAPR-1 is NA , and the successor status is ???. I need it for distributing 10Mhz ref-clock to Counters (HP,Racal,Phillips), a Rigol Sig-gen& maybe Oscilloscopes etc. It's for "better than ocxo/hobby use" , and not Tnut

Re: [time-nuts] WWVB BPSK Receiver Project? (fwd)

ehydra wrote: I wonder because ALL of the shown circuits in his pdf are AC-coupled. It is maybe possible to servo-loop with OpAmps but surely not worth the effort. Useful too as a Scope FET-probe. Not really the gain inaccuracy is somewhat excessive. One can do much better with the right ci

Re: [time-nuts] OP-Amps for 10MHz distribution...?

Charles P. Steinmetz wrote: Bill wrote: At what frequency do you have 1 nv per square root Hz with opamp and what opamp ? With most op-amps suitable for a 10 MHz distribution amp, the input voltage noise is specified at 100 kHz or greater. For example, the OPA653 that Bruce tested is speci

Re: [time-nuts] time-nuts] OP-Amps for 10MHz distribution...?

John Miles wrote: Apologies if this is a dupe -- I'm not sure it ever made it to the list: The attached plot indicates the phase noise performance obtainable with a wideband FET (OPA653) input opamp. With a 10MHz +9dBm input, the phase noise floor is around -163dBc/Hz at 1kHz offset and aro

Re: [time-nuts] OP-Amps for 10MHz distribution...?

For the OPA653 the noninverting configuration has lower distortion at least for 2V pp outputs. Bruce gary wrote: Just a FYI, some op amps have lower distortion in inverting mode than as a follower. This is not intuitively obvious since a follow has maximum feedback, which would imply the best

Re: [time-nuts] OP-Amps for 10MHz distribution...?

evice? Put another way, if you drive it with +13 dbm do all the numbers get 5 db better? I doubt very many of us will be worrying about weather it's below -153 at 10 Hz or not? Bob On Feb 28, 2012, at 5:42 AM, Bruce Griffiths wrote: > The attached plot indicates the phase noise perf

Re: [time-nuts] OP-Amps for 10MHz distribution...?

power can you run through the device? Put another way, if you drive it with +13 dbm do all the numbers get 5 db better? I doubt very many of us will be worrying about weather it's below -153 at 10 Hz or not… Bob On Feb 28, 2012, at 5:42 AM, Bruce Griffiths wrote: The attached plo

Re: [time-nuts] CCD lock detection

If and only if you want to reduce the SNR substantially. A typical glass fibre will capture insufficient light to be useful compared to the standard arrangement using a photocell. Plastic fibres are not usable as the temperature in the vicinity of the absorption cell is too high. Bruce Tom Kn

Re: [time-nuts] FE-5680A's suitability for use as a 10 MHz reference for microwave transverters

paul swed wrote: Clint a good read and a fine approach. If and only if the high phase noise pedestal exhibited by the buffer amplifier that extends to offsets of a few hundred kHz or so isn't an issue. The relatively low isolation between the 10MHz outputs may also be an issue. By accid

Re: [time-nuts] Building a GPSDO & trouble using Jupiter-T

AM, Bruce Griffiths< bruce.griffi...@xtra.co.nz> wrote: The 10kHz is continuous but its phase jerked on the second. The new phase is held until the next jerk. Bruce Azelio Boriani wrote: Ah, is it a burst of 10KHz once a second? I don't have a Jupiter-T and I&#

Re: [time-nuts] Building a GPSDO & trouble using Jupiter-T

The 10kHz is continuous but its phase jerked on the second. The new phase is held until the next jerk. Bruce Azelio Boriani wrote: Ah, is it a burst of 10KHz once a second? I don't have a Jupiter-T and I'm a PPS-type discplining fan but I thought it was a continuous 10KHz. On Mon, Jan 30, 201

Re: [time-nuts] Building a GPSDO & trouble using Jupiter-T

What about the phase jerk (details given in the datasheet) applied to the 10KHz burst once per second? Bruce Azelio Boriani wrote: Timing GPS receivers usually have the sawtooth correction message and I saw an application of a delay line to correct the PPS before using it. Of course if you tim

Re: [time-nuts] Building a GPSDO & trouble using Jupiter-T

Don't confuse the PLL loop "time constant " with the time constant of the analog or digital filter. They are not the same. Bruce Ray Xu wrote: Hi Chris Thanks for your helpful input. What do you mean by "average"? Do you mean that the GPS and PLL must be kept on for "20 minutes to hours", o

Re: [time-nuts] Looking for Harris/Qbit amplifers

The Q-bit amplifiers tend to use directional coupler feedback as detailed in several of their patents. Bruce John Ackermann N8UR wrote: Hi Rob -- Thanks for the pointer. I should have been more detailed -- I was hoping to find the same model number as I'm building several copies of a signa

Re: [time-nuts] Looking for Harris/Qbit amplifers

ed breya wrote: Yes, those are handy amplifier modules - I always save any that I find in surplus RF gear. You can easily replicate the functions with modern gain blocks, or your own circuit using discrete parts, if you don't need the "drop-in" hermetic package style. The ones with about 10 d

Re: [time-nuts] mixers for frequency measurement

Chris Albertson wrote: I want to get set up to make accurate frequency stability measurements at reasonable cost. I think mixers are the way to do that. I'll set up a single mixer first them later learn to use the double mixer technique. But I will use the simpler single mixer to try out the

Re: [time-nuts] Temperature and signal amp for 'Bay FE-5680A?

Attila Kinali wrote: On Thu, 12 Jan 2012 00:50:35 +1300 Bruce Griffiths wrote: Thats certainly not the case in the FS730C, the risetime isnt appreciably affected by the small (4R7) damping resistor in series with Vcc. Adding a series damping resistor in series with the output is

Re: [time-nuts] Temperature and signal amp for 'Bay FE-5680A?

Hal Murray wrote: The TADD-3 uses 3 AC drivers in parallel, each going through a 51 ohm resistor. Changing those resistors to 150 ohms should work. Maybe a bit lower to account for the impedance in the drivers. I'd probably check it with a scope. bruce.griffi...@xtra.co.nz said:

Re: [time-nuts] Temperature and signal amp for 'Bay FE-5680A?

David wrote: On Tue, 10 Jan 2012 21:57:49 +1300, Bruce Griffiths wrote: Hal Murray wrote: The TADD-3 uses 3 AC drivers in parallel, each going through a 51 ohm resistor. Changing those resistors to 150 ohms should work. Maybe a bit lower to account for the impedance in the

Re: [time-nuts] Temperature and signal amp for 'Bay FE-5680A?

Hal Murray wrote: davidwh...@gmail.com said: I looked at the TADD-3 design and it sacrifices back termination impedance for signal swing which results in ringing but I presume not too much if people were using it successfully. If the far end (receiver) is terminated to match the coax,

Re: [time-nuts] HP Z3817A Reverse Engineering

Ed Palmer wrote: On 1/9/2012 8:58 AM, Robert Benward wrote: Hi Ed, I just tracked down Fluke and he offered me one, and per your advice I will try and confirm the condition before purchasing from him (not that there are alternate sources) . I have to say that fluke.l did guarantee that the

Re: [time-nuts] OffsetGenerator

Attila Kinali wrote: Moin Ulrich, On Sun, 25 Dec 2011 13:11:24 +0100 "Ulrich Bangert" wrote: a) A clock shaper as designed by Bruce Griffiths based on a ADCMP600 that should work well to over 100 MHz. I had a short look at the schmeatics and something caught my eyes:

Re: [time-nuts] Low noise power supplies for time nuts circuitry

Another potential problem is that the cascaded emitter follower circuit shown is likely to oscillate in the VHF region. An unbypassed resistor in series with the base of each emitter follower should be used. Bruce Bruce Griffiths wrote: Omitting the output bypass cap in the single transistor

Re: [time-nuts] Low noise power supplies for time nuts circuitry

Omitting the output bypass cap in the single transistor Wenzel cancellation circuit is somewhat misleading in that it reduces the high frequency attenuation, All his other circuits include such caps. A simple tweak (adjusting a resistor ratio) which makes the shunt transistor collector current

Re: [time-nuts] SLIP vs Ethernet for NTP

Prell is the Danish equivalent of contact bounce. Poul-Henning is a Dane so the odd Danish word tends to creep in. Bruce Bill Hawkins wrote: Fascinating thread. Poul-Henning Kamp mentions "contact prell." Google can't find it. Even quoted, I get shampoo and people with that name. I understan

Re: [time-nuts] Cable delay correction for Tbolt Cs substitude

Its merely a calculation of the change in inductance due to the temperature induced change in skin depth due to the resistivity tempco of the inner conductor wich varies the inductance per unit length. Since RG6 uses a copper plated steel inner conductor there may be significant differences in

Re: [time-nuts] OT: New BVAs in the house

Magnus Danielson wrote: Fellow time-nuts, While spammer-discussions seems to be the current topic, excuse me for tossing in an on-topic issue. Today I came home with a pair of 5 MHz OSA 8695 SC-cut mini-BVA oscillators. Essentially SC-cut BVAs in a double-oven assembly. Never seen those be

Re: [time-nuts] You can build a fountain from the things you find at home...

J. Forster wrote: Boy I have to go back and check. I thought fountains used lasers and such to slow the atoms down. That's a trap. "Optical molasses". A fountain essentially makes a beam and probes it orthogonal to the beam, where the Dopplar shifts are low. The beam basically makes all t

Re: [time-nuts] You can build a fountain from the things you find at home...

Poul-Henning Kamp wrote: In message , Robert Darlington writes: So I find that somewhat surprising (Aluminum as a material for UHV systems) because they outgas water -for months. Anodized aluminum is especially bad! Did they make any suggestions on cleaning the oxide off before pumping do

Re: [time-nuts] Allan Deviation Calulations

mike cook wrote: Le 22/09/2011 12:35, Martyn Smith a écrit : Hello, I'm trying to measure the Allan Deviation of an amplifier and need help with the maths. My measurement process uses the SR620 in time interval mode and I make one measurement per second for about a day. I then use Ulrichs

Re: [time-nuts] Sine to LVDS

li...@lazygranch.com wrote: I don't have one handy, but didn't the Motorola ECL manual or maybe application guide show how to make wideband circuits (comparators for example) out of ECL gates. (1989 was the last time I did any ECL. What a pain in the arse technology.) ___

Re: [time-nuts] Sine to LVDS

Jim Lux wrote: On 9/9/11 6:37 AM, ehydra wrote: Hi Bruce - Do you have a reference to read on for this? I imagine that's the standard cascade of limiters used in zero crossing detectors.. google for JPL and Greenhall to get started. I can't remember the exact cite (or even if Greenhall wa

Re: [time-nuts] Sine to LVDS

On 9/9/2011 12:29 PM, Javier Herrero wrote: Thanks for the reminder :) Te available 180MHz signal has that level, and it is quite heavily bandpass filtered, since it comes from a multiplier chain from an 45MHz OCXO, so the ADCMP604 will fit nicely Best regards, Javier El 09/09/2011 13:07, Bruc

[time-nuts] Fwd: Re: Sine to LVDS

style setup would add much. More or less - if the input speed is already faster than the output logic, is there actually a benefit? Bob -Original Message- From: time-nuts-boun...@febo.com [mailto:time-nuts-boun...@febo.com] On Behalf Of Bruce Griffiths Sent: Friday, September 09, 201

Re: [time-nuts] Sine to LVDS

Javier Herrero wrote: Hello all, I think that the same question that has been discuted here a zillion times but usually around 10MHz... anyway, what would be the best way to convert a sine wave to a LVDS clock (preferably duty cycle 50%) at 180MHz? Texas Instruments suggest a LVDS receiver

Re: [time-nuts] any HP 5370B Available or other TIC

Javier Herrero wrote: El 18/08/2011 08:37, Bruce Griffiths escribió: DMTD or dual mixer time difference. An all digital version (DDMTD like that used in CERN's White Rabbit) is also possible 3 (and M) input versions are also feasible. Either an FPGA or a CPD plus a microprocessor are req

Re: [time-nuts] any HP 5370B Available or other TIC

Paul Cianciolo wrote: Hello Folks, I am looking for an instrument that is better than Fluke 103a comparator. The purpose of this piece of equipment is help me learn more about oscillators and characterizing them The HP5370B is the TIC I keep hearing about but I am not glued to that make or mo

Re: [time-nuts] Trimble T-Bolt Power Supply Question

I have used one of the Cisco34-0874-01 supplies to run a Thunderbolt for a couple of years. It appears to work well. However I haven't measured the resultant 10MHz output phase noise spectrum. I am about to power another Thunderbolt with an open frame linear supply (723 regulators with 2N3055 se

Re: [time-nuts] Why not TAI?

Magnus Danielson wrote: On 10/08/11 09:16, Bruce Griffiths wrote: Attila Kinali wrote: On Fri, 15 Jul 2011 05:57:45 + "Poul-Henning Kamp" wrote: Everybody but the time-lords have always been told to stay away from TAI in the strongest possible terms by said time-lords, who agai

Re: [time-nuts] Why not TAI?

Attila Kinali wrote: On Fri, 15 Jul 2011 05:57:45 + "Poul-Henning Kamp" wrote: Everybody but the time-lords have always been told to stay away from TAI in the strongest possible terms by said time-lords, who again and told the world to use UTC. May i ask what the reason was to s

Re: [time-nuts] FTS 1050A

Max Robinson wrote: If you use a D flip flop as a mixer it will produce the difference only. You have to get the D and clock signals right I forget which one has to be the highest frequency to make that work. Regards. Max. K 4 O D S. Why? A D flipflop works well as a mixer when either the

Re: [time-nuts] FTS 1050A What to do??

Paul A. Cianciolo wrote: Hello Folks, In my collection of stuff, I found an FTS 1050a in good condition. It has been sitting for 5 years, and I decided to fire it up last night. It works. Opened it up and took a look inside. The main reference is a large box which I assumed was filled with foam

Re: [time-nuts] Spectracom 8140 distribution amplifier and the Taps- some application info

walter shawlee 2 wrote: There have been many questions posted here about the units, here are a few answers I have collected: 1. the 8140 can drive up to 25 total downstream 8410T taps on the combined outputs. The mopdels are frequency specific, and are not easily changed, 10Mhz is the most co

Re: [time-nuts] 5370 firmware hacking status report

Poul-Henning Kamp wrote: In message<77e0fba5-aa78-4399-9562-d1274e109...@jks.com>, John Seamons writes: I would worry a bit about the PLL locking too, but I have no idea how to actually measure it. I think the 1sec max gate-time is related to the eventcounter width, but it might be possible to

Re: [time-nuts] 5370 firmware hacking status report

John Seamons wrote: Some progress since February's discussion: My m6800 emulator running the 5370 firmware has been moved from the Linux box to a little 32-bit microcontroller on it's own small evaluation-kit board. Pictures here: http://jks.com (click on images for larger versions) You talk t

Re: [time-nuts] 50:50 duty from a PRS10

Dave M wrote: Hello, I have a PRS10 rubidium which gives a 1pps output. The output is a 10 us positive pulse. I need to convert that to a 50:50 duty cycle pulse. Still 1pps. I'm hoping for a simple circuit rather than having to use a pic. I don't mind a bit of propagation delay, but I nee

Re: [time-nuts] Reference oscillator requirements when measuring ADEV ?

Mark Spencer wrote: I'm curious in knowing if there are any rules of thumb as to how much better a reference oscillator needs to be than the device under test when measuring ADEV ? To provide a bit of context to my question I'm using a HP 5370B to repeatedly measure the time interval between

Re: [time-nuts] DDS'ery

Jim Lux wrote: On 6/20/11 9:46 AM, Luis Cupido wrote: Gracias, Javier. As you read in my previous email I'm basically worried about close-in spurs (those that will pass through the PLL loop filter). will digest that 4th section... tks. ... Since I'm inside an FPGA... I'm eager to get spurs d

Re: [time-nuts] Low noise power supply recommendations

Will Matney wrote: As far as the power supply is concerned, I think I am going to go with Ni-Cad batteries, and regulate the voltages. I think what they had was nothing more than four step voltages from the battery supply, going from 3, 6 (7), 12, and 24 Vdc, or X2 of the other. From what I saw i

Re: [time-nuts] Advanced 5 to 10 MHz doubler

S. Paramithiotti -Original Message- From: time-nuts-boun...@febo.com [mailto:time-nuts-boun...@febo.com] On Behalf Of Bruce Griffiths Sent: martedì 15 febbraio 2011 22.19 To: Discussion of precise time and frequency measurement Subject: Re: [time-nuts] Advanced 5 to 10 MHz doubler Simulati

Re: [time-nuts] Fluke PM6681 triggering

g" tube to a pancake style detector for these measurements. On 6/5/2011 2:12 AM, Bruce Griffiths wrote: Is the GM tube internally or externally quenched? Its necessary to quench each avalanche discharge either by using an internal quenching gas (eg a halogen) or to use suitable circuitry

Re: [time-nuts] Fluke PM6681 triggering

ew counter. Thanks for the feedback -- any more welcomed. -Rex On 6/5/2011 12:42 AM, Bruce Griffiths wrote: A Geiger Muller (GM) tube produces an output pulse as a result of an avalanche discharge in the gas filled tube initiated by the passage of ionising radiation through the tube. A high

Re: [time-nuts] Fluke PM6681 triggering

A Geiger Muller (GM) tube produces an output pulse as a result of an avalanche discharge in the gas filled tube initiated by the passage of ionising radiation through the tube. A high voltage is initially maintained between an outer usually cylindrical electrode and an inner small diameter wire

Re: [time-nuts] Sidereal timekeeping

Jim Lux wrote: On 5/16/11 2:58 PM, iov...@inwind.it wrote: Neville, at present I have not enough skill with micros to solve the problem. I think I will try modifying a crystal. This would not be that difficult using a lapping sheet or the like. And opening the can would be quite easy using hot

Re: [time-nuts] Dist Amps Questions

W2HX wrote: Hi all, I am close to closing in on a video distribution amp for a GPSDO for use in 10 MHz reference signals for various test equipment and had a few questions. 2. Many of these amps have LOOP through connections to expand the number of outputs (in ->loop->in). I often se

Re: [time-nuts] 60hz disciplined watch follow up

tom jones wrote: My orignal post that 60hz light flicker received at citizen ecodrive solarcells is used to discipline the watchs rate, needs a little correction to my post as brought to my attention by the replies. Yes it is actually 120hz flicker 60 positive cycle flickers and 60 negative

Re: [time-nuts] Dist Amps Questions

David VanHorn wrote: /worry || be_happy. 1. 50/75 ohm question. I know that putting 50 ohm source into a 75 ohm device will cause SWR. I know that the total power delivered to the device will be the difference between forward power and reflected power. So that doesn't seem bad, just mi

Re: [time-nuts] 60hz disciplined watch (really?)

Robert Atkinson wrote: Hi, I think this is incorrect, 1/ My ecodrive that I bought in the USA does not run 20% slow here in the UK 2/What about incandesent lamps and those with inverters? As has been pointed out in an earlier post detecting the second harmonic modulation in the light output

Re: [time-nuts] cheap 5V OCXO in 14DIP has about 1E-9 drift per day

wrote: On 04/16/2011 10:50 PM, Bruce Griffiths wrote: Bruce Griffiths wrote: Oz-in-DFW wrote: On 4/9/2011 11:29 AM, Greg Broburg wrote: I expect that I am missing something obvious here a little nudge may help. Regards; Greg What y

Re: [time-nuts] cheap 5V OCXO in 14DIP has about 1E-9 drift per day

Magnus Danielson wrote: On 04/16/2011 10:50 PM, Bruce Griffiths wrote: Bruce Griffiths wrote: Oz-in-DFW wrote: On 4/9/2011 11:29 AM, Greg Broburg wrote: I expect that I am missing something obvious here a little nudge may help. Regards; Greg What you are missing is that the concept

Re: [time-nuts] PIC processor CTMU module used for sub-ns TIC applications?

beale wrote: I see Microchip application note AN1375 at http://ww1.microchip.com/downloads/en/AppNotes/01375a.pdf suggests that the CTMU module included in some recent PIC parts, for example PIC18F46J11 can be used as a TIC building block for interpolating time intervals with sub-ns resolutio

Re: [time-nuts] cheap 5V OCXO in 14DIP has about 1E-9 drift per day

Bruce Griffiths wrote: Oz-in-DFW wrote: On 4/9/2011 11:29 AM, Greg Broburg wrote: I expect that I am missing something obvious here a little nudge may help. Regards; Greg What you are missing is that the concept only applies to small integer (2 or 3) division ratios and won't wo

Re: [time-nuts] cheap 5V OCXO in 14DIP has about 1E-9 drift per day

Oz-in-DFW wrote: On 4/9/2011 11:29 AM, Greg Broburg wrote: I expect that I am missing something obvious here a little nudge may help. Regards; Greg What you are missing is that the concept only applies to small integer (2 or 3) division ratios and won't work as speculated here.

Re: [time-nuts] cheap 5V OCXO in 14DIP has about 1E-9 drift per day

Bruce Griffiths wrote: Bruce Griffiths wrote: Hal Murray wrote: bruce.griffi...@xtra.co.nz said: The 16MHz is necessary for the loop to function: The mixer mixes down the 26MHz to a pair of conjugate frequencies, 10MHz and 16MHz. Thermal and device noise is sufficient to start the process

Re: [time-nuts] cheap 5V OCXO in 14DIP has about 1E-9 drift per day

Bruce Griffiths wrote: Hal Murray wrote: bruce.griffi...@xtra.co.nz said: The 16MHz is necessary for the loop to function: The mixer mixes down the 26MHz to a pair of conjugate frequencies, 10MHz and 16MHz. Thermal and device noise is sufficient to start the process. 10MHz = 26MHz - 16MHz

Re: [time-nuts] BNC question

Chuck Harris wrote: Greg Broburg wrote: receivers used 75 ohmantenna inputs, so they often used 75 ohm BNC connectors. I had remembered that it was a 75 ohm that would damage a 50 ohm socket. This article states that a 50 ohm would damage a 7

Re: [time-nuts] BNC question

Magnus Danielson wrote: On 04/10/2011 01:51 AM, Mike S wrote: At 06:53 PM 4/9/2011, Joseph Gray wrote... I have an old Arcnet hub that I want to salvage the isolated BNC connectors from. Arcnet used 93 Ohm coax. I know that there are 50 Ohm and 75 Ohm versions of BNC connectors, but the ones fr

Re: [time-nuts] cheap 5V OCXO in 14DIP has about 1E-9 drift per day

There are also loop gain and phase shift requirements to be met for stable operation (ie with no asynchronous modes). Bruce Greg Broburg wrote: 10.05 = 26 - 15.95 15.95 = 26 - 10.05 This pair of equations is insufficient to define that the ratio between these two frequencies

Re: [time-nuts] cheap 5V OCXO in 14DIP has about 1E-9 drift per day

Hal Murray wrote: bruce.griffi...@xtra.co.nz said: The 16MHz is necessary for the loop to function: The mixer mixes down the 26MHz to a pair of conjugate frequencies, 10MHz and 16MHz. Thermal and device noise is sufficient to start the process. 10MHz = 26MHz - 16MHz 16MHz = 26MHz

Re: [time-nuts] cheap 5V OCXO in 14DIP has about 1E-9 drift per day

am missing something obvious here a little nudge may help. Regards; Greg On 4/7/2011 1:23 PM, Chris Albertson wrote: On Thu, Apr 7, 2011 at 12:01 PM, Bruce Griffiths wrote: A conjugate regenerative divider with 2 parallel (16MHz& 10MHz) low Q bandpass filters should suffice. Never ha

Re: [time-nuts] cheap 5V OCXO in 14DIP has about 1E-9 drift per day

A conjugate regenerative divider with 2 parallel (16MHz & 10MHz) low Q bandpass filters should suffice. Bruce Peter Loron wrote: I can't speak for anybody else on the list, but if there was an inexpensive converter to get a good stable 10MHz signal from one of the cheap 26MHz OCXOs, I'd sure

Re: [time-nuts] Phase noise at 1-100Hz

John Miles wrote: Javier Herrero wrote: Hello, I will need to measure the phase noise of a 35MHz oscillator in the range of 1 to 100Hz (well... and also at a higher range but this is no problem), and I would like to know about the different alternatives. I would like not to have to me

Re: [time-nuts] Phase noise at 1-100Hz

Javier Herrero wrote: Hello, I will need to measure the phase noise of a 35MHz oscillator in the range of 1 to 100Hz (well... and also at a higher range but this is no problem), and I would like to know about the different alternatives. I would like not to have to mess too much with mixers an

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