Re: [time-nuts] Thunderbolt versus Home made

Didier Juges wrote: > Dr Bruce Griffiths wrote: > >> Didier Juges wrote: >> >> >>> Angus wrote: >>> >>> >>> >>>> Although that's not what I was talking about doing above, I think that >>&

Re: [time-nuts] Good Phase-noise?

Larry Gadallah wrote: > Hello all: > > I considering a do-it-yourself GPSDO, and I started by looking for a > good OCXO. I have been given a quote for a unit with the following > phase-noise numbers: > > -120 dBc/Hz at 10 Hz > -145 dBc/Hz at 100 Hz > -155 dBc/Hz at 1 kHz > -160 dBc/Hz at 10 KHz > -

Re: [time-nuts] Low noise frequency multiplication

Stephan Sandenbergh wrote: > Hi all, > > > > How difficult is it to multiply a frequency standard from 10MHz to 100MHz? > > > > I found the recent discussion about amplifying a 10MHz OCXO output from 5dBm > to 15dBm very interesting. Thanks Bruce for sending me that common base > circuit schem

Re: [time-nuts] Good Phase-noise?

Larry Gadallah wrote: > On 2/28/07, [EMAIL PROTECTED] <[EMAIL PROTECTED]> > wrote: >> Message: 6 >> Date: Thu, 01 Mar 2007 12:05:38 +1300 >> From: Dr Bruce Griffiths <[EMAIL PROTECTED]> >> Subject: Re: [time-nuts] Good Phase-noise? >> To: Disc

Re: [time-nuts] Good Phase-noise?

Larry Gadallah wrote: > Hello Bruce: > >> Larry >> >> Obtaining a lower phase noise COTS OCXO in this price range is unlikely >> unless Wenzel oscillators are unusually cheap. >> >> http://www.wenzel.com/catalog.html#HF%20Oscillators > > Is Wenzel the leader of the pack in this sort of technology?

Re: [time-nuts] Low noise frequency multiplication

Stephan Sandenbergh wrote: > Hi Rick, > > You are absolutely right - I should've mentioned the specs first. > > It is an Oscilloqaurtz 8788 locked to GPS. > > Phase noise at 10MHz: > Hz dBc/Hz > 1 -100 > 10 -130 >

Re: [time-nuts] Low noise frequency multiplication

Stephan Sandenbergh wrote: > Hi Bruce, > > Thanks for explaining - the picture is starting to become clearer. I knew > there must be a reason why commercial multipliers are so expensive. > > If I understand you correctly the variation in phase (or group delay) caused > by a variation in temperatur

Re: [time-nuts] Low noise frequency multiplication

Pete wrote: > Bruce, > > Can you please provide some references to phase noise problems/performance > of the passive components you mention? > > Pete Rawson > > > ___ > time-nuts mailing list > time-nuts@febo.com > https://www.febo.com/cgi-bin/mailman/l

Re: [time-nuts] Low noise frequency multiplication

David I. Emery wrote: > On Fri, Mar 02, 2007 at 04:02:39AM +1300, Dr Bruce Griffiths wrote: > > >> Its not just the temperature coefficients, real inductors and capacitors >> have inherent phase noise. >> Silver mica capacitors can be very bad as are ferrite core ind

Re: [time-nuts] Low noise frequency multiplication

Ulrich Bangert wrote: > Hi foks, > > I want to put forward a similar but slightly different question: > > Suppose I need an clock running at around 50 Mhz for an DDS. Because of > the DDS it need not be exactly 50 MHz, can be 52 or 54 MHz too. > Basically this clock shall be derived from a 10 MHz

Re: [time-nuts] External clock for Analog to Digital Converter in GPS Rx front-end

Bilal Amin wrote: > Hi Everyone, > > I am working on Jitter in Analog to Digital Converters(ADCs) for GPS receiver > front-end. I am trying to setup an experiment to see the effects of jitter in > real time ADCs. I have an ADC evaluation board with external clock input for > sampling (i.e Sampli

Re: [time-nuts] External clock for Analog to Digital Converter in GPS Rx front-end

Bilal Amin wrote: > Hi Everyone, > > I am working on Jitter in Analog to Digital Converters(ADCs) for GPS receiver > front-end. I am trying to setup an experiment to see the effects of jitter in > real time ADCs. I have an ADC evaluation board with external clock input for > sampling (i.e Sampli

Re: [time-nuts] Low noise frequency multiplication

Stephan Sandenbergh wrote: > Hi Said, > > The DDS idea that you (and Ulrich) suggest sounds like a good plan. > However, to me your predictions sound overly optimistic. > > >> Said wrote: >> > > >> But let's say these are as good as advertised, and for me that would mean >> say better th

Re: [time-nuts] Low noise frequency multiplication

Stephan Sandenbergh wrote: > Darn, the table is a mess. Here is the corrected one: > > LVPECL Outputs > HzdBc/Hz > 1 ? > 10-127 > 100 -145 > 1k-153 > 10k -158 > 100k -158 > 1M-158 > > 10MHz OCXO > HzdBc/Hz > 1 -100 > 10-130 > 100 -152 > 1k-160

Re: [time-nuts] External clock for Analog to Digital Converter in GPS Rx front-end

Bilal Amin wrote: > - Original Message - > From: "Dr Bruce Griffiths" <[EMAIL PROTECTED]> > To: "Discussion of precise time and frequency measurement" > > Sent: Friday, March 02, 2007 6:10 PM > Subject: Re: [time-nuts] External clock for An

Re: [time-nuts] Suspected Spam: External clock for Analog toDigital Converter in GPSRx front-end Rx front-end

Bilal Amin wrote: > Hi John, > > Thank you for your email. I am also looking at the PM method to solve my > problem. I have a HP signal generator and I can use it to generate an RF > signal and then modulate it with noise from the modulating input of the > signal generator. > I need some suggest

Re: [time-nuts] External clock for Analog to Digital Converter in GPS Rx front-end

John Miles wrote: >> You can easily add noise to a sinewave, for example a hybrid combiner >> can be used to combine the output of a sinewave generator and a noise >> source. >> > > That's just going to create AM noise, isn't it? He wants jitter (phase > modulation), I believe. > > -- john, K

Re: [time-nuts] External clock for Analog to Digital Converter in GPS Rx front-end

John Miles wrote: > Well, sure, but it also causes all kinds of secondary distortion effects > (such as potential clipping at the rails of whatever you're feeding the > signal into). I don't think AM'ing the signal when you want PM is a good > idea, when it's so easy to apply PM by itself. > > --

Re: [time-nuts] External clock for Analog to Digital Converter inGPS Rx front-end

Bilal Amin wrote: > Hi John and Bruce, > > Thank you for your ideas. Now I have a much better picture for the > experiment using the comparator. Now, my only concern is a noise generator. > I have searched and found out that all the commercially available now > generators are very expensive and

Re: [time-nuts] External clock for Analog to Digital Converter inGPS Rx front-end

Bilal Amin wrote: >> Hi John and Bruce, >> >> Thank you for your ideas. Now I have a much better picture for the >> experiment using the comparator. Now, my only concern is a noise generator. >> I have searched and found out that all the commercially available now >> generators are very expensiv

Re: [time-nuts] External clock for Analog to Digital Converter inGPS Rx front-end

Bilal Amin wrote: > Hi John and Bruce, > > Thank you for your ideas. Now I have a much better picture for the > experiment using the comparator. Now, my only concern is a noise generator. > I have searched and found out that all the commercially available now > generators are very expensive and

Re: [time-nuts] External clock for Analog to Digital Converter inGPS Rx front-end

Arnold Tibus wrote: > Hi, > HP was using in their 500MHz counter 5345A a noise generator > (zener diode with amplifier on PC board 'A8 PLL Multiplier Noise Generator > board') to modulate via a varactor and a tank circuit the 10 MHz > reference frequency coming from the ocxo 10811A. > "4-126, A

Re: [time-nuts] Setting Osc Frequencies

Tom Van Baak wrote: > Don, > > Yes, using an oscilloscope in this way is a time-honored > trick to observe slow changes in relative phase over time. > > It gets even better if you have access to a storage 'scope > or variable persistence because then you can get a rough > sense of short-term jitter

Re: [time-nuts] Setting Osc Frequencies

Dr Bruce Griffiths wrote: > Tom Van Baak wrote: > >> Don, >> >> Yes, using an oscilloscope in this way is a time-honored >> trick to observe slow changes in relative phase over time. >> >> It gets even better if you have access to a storage 'scope

Re: [time-nuts] External clock for Analog to Digital Converter inGPS Rx front-end

Arnold Tibus wrote: Thanks Bruce, 'it generates poses some interesting challenges' sounds interesting, could you give some little details to get better idea of it? many thanks, Arnold, DK2WT Arnold As can be seen from the attached schematic, the 50X frequency multiplier simplifies achie

Re: [time-nuts] Setting Osc Frequencies

Tom Attached schematic depicts an updated version of the digital part of the K34-5991A. Using LCX CMOS flipflops reduces the cost significantly, but the maximum usable input frequency is also reduced, however operation to around 20MHz should be OK. The 2 stage synchroniser connected to the out

Re: [time-nuts] Setting Osc Frequencies

Bill Janssen wrot >> I built my own version of this scheme and it works OK but mine has some >> "issues" >> So I would like to have at least three of these.to replace my one. >> >> Anyone willing to take on the job of designing a circuit board? >> >> I log my results with a A-D converter and my Ba

Re: [time-nuts] Setting Osc Frequency

VK3YV wrote: > Hi, Tom and Bruce, many thanks for the help so far. Now I realise that I > will have to divide my 10MHZ reference down to match the 5MHZ from the > sulzers and also down to 1MHZ to use as an external ref. for the 5245L's. > How do I change the TTL from the dividers back to a Sine w

Re: [time-nuts] Setting Osc Frequencies

Bill Janssen wrote: > I built my own version of this scheme and it works OK but mine has some > "issues" > So I would like to have at least three of these.to replace my one. > > Anyone willing to take on the job of designing a circuit board? > > I log my results with a A-D converter and my Ba

Re: [time-nuts] Setting Osc Frequencies

Hal Murray wrote: >> I can design a suitable circuit but may need someone else to do the >> layout as my PCB layout software is rather ancient. >> > > I'll be willing to turn the crank on the board layout as long as a few people > are willing to double check whatever I do. (and nobody is in

Re: [time-nuts] Setting Osc Frequencies

Robert Atkinson wrote: > Hi Bruce, > It's a while since I looked at the HP circuit and patent, but if I > recall correctly a lot of the performance relied on the input circuit. > This used a line receiver with feedback. When I looked there did not > seem to be an equivalent receiver chip available.

Re: [time-nuts] Setting Osc Frequencies

The attached schematic depicts the logic circuitry for the revised phase comparator Each of the 2 phase outputs is low pass filtered and buffered by an opamp. Specifications: Max input frequency 20MHz 2 quadrature phase outputs. nonlinearity < 5nS at either end of range. Input voltage (at compar

Re: [time-nuts] 5370a manual

Jeroen Bastemeijer wrote: > Dear All, > > I have problems accessing the 5370A manual on the Agilent website?! > Accessing the 5370B manual is nor problem. Any suggestions? > > Thanks, Jeroen > > Jeroen Try http://www.g8wrb.org/data/HP/HP5370A.pdf Bruce __

Re: [time-nuts] Setting Osc Frequencies

Robert Atkinson wrote: Hi Bruce, It's a while since I looked at the HP circuit and patent, but if I recall correctly a lot of the performance relied on the input circuit. This used a line receiver with feedback. When I looked there did not seem to be an equivalent receiver chip available. I'm awa

Re: [time-nuts] Setting Osc Frequencies

Dr Bruce Griffiths wrote: Lars Karlsson wrote: Bruce- There is a minor problem in the schematic. A capacitor have to be added between R103 and R104. This will prevent the bias on pin 3 from being shorted to the ground via R101 and R102. Also, C103 is not required as long as the diodes

Re: [time-nuts] Setting Osc Frequencies

The attached input circuit schematic has values for all components. Bruce ___ time-nuts mailing list time-nuts@febo.com https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts

Re: [time-nuts] Low Drop Out Voltage Regulator

Brian Kirby wrote: > Can anybody recommend a low drop out voltage regulator that will work > with a 2 volt input differential, and a output of 22 volts at 2 amps ? > > What I have in mind is a 28 volt DC power supply, and 24 volt batteries, > and a rubidium oscillator that will run at 22 volts. > >

Re: [time-nuts] Low Drop Out Voltage Regulator

Dr Bruce Griffiths wrote: > Brian Kirby wrote: > >> Can anybody recommend a low drop out voltage regulator that will work >> with a 2 volt input differential, and a output of 22 volts at 2 amps ? >> >> What I have in mind is a 28 volt DC power supply, and 24 vol

Re: [time-nuts] Delay through GPS antenna splitter/amplifier -- an answer, and a question

Tim Shoppa wrote: > John Ackermann N8UR <[EMAIL PROTECTED]> wrote: > >> But we're time-nuts... we DO worry about those things. :-) >> >> While we were at it with the network analyzer, we did FDR (frequency >> domain reflectometry) to measure the cable delay to the antenna, and I >> spent yeste

Re: [time-nuts] Delay through GPS antenna splitter/amplifier -- an answer, and a question

Tim Shoppa wrote: > Dr Bruce Griffiths <[EMAIL PROTECTED]> wrote: > >>> At the lab I worked at in the 80's, all the cables hanging on >>> the wall-racks were calibrated and labeled in nanoseconds. >>> >>> But... after the ECL signals

Re: [time-nuts] Delay through GPS antenna splitter/amplifier -- an answer, and a question

Hal Murray wrote: >> So the cable delay should be a multiple of 317.375...ps. >> > > What's the thermal coefficient of coax? > > > Hal Typically around 50-100ppm/C depending on the coax. High velocity cables have lower tempcos Bruce ___ time-n

Re: [time-nuts] Delay through GPS antenna splitter/amplifier -- an answer, and a question

Hal Murray wrote: So the cable delay should be a multiple of 317.375...ps. >>> What's the thermal coefficient of coax? >>> >> Typically around 50-100ppm/C depending on the coax. >> High velocity cables have lower tempcos >> > > Handwaving... > > 100 ft of cable is 70n

Re: [time-nuts] An Excellent Tutorial on Precision Clocks

Tom Clark, K3IO wrote: >I just stumbled on an excellent tutorial on low-noise clocks -- >National Semiconductors free downloadable "[1]Clock Conditioner >Owner's Manual". This 88 page document is a 3.7 MB PDF. >73 de Tom, K3IO > > References > >1. > http://www.national.com/appi

Re: [time-nuts] An Excellent Tutorial on Precision Clocks

Matt Ettus wrote: > I was just investigating this very issue. It seems that every program > you use to compute these impedances comes up with different answers, > sometimes wildly different. Anyone have a free program they trust > with this sort of thing? > > Matt > &

Re: [time-nuts] Question for the cesium nuts.

Hal Murray wrote: >> http://www.kvarz.com/pdf/05%20CH1-75A.pdf (Active MASER) >> http://www.kvarz.com/pdf/06%20CH1-76A.pdf (Passive MASER) >> > > What do "active" and "passive" mean wrt masers? > > >From the above data sheets, active means bigger and better. (and probably > more expensive) >

Re: [time-nuts] Producing jitter with Phase Modulation

Bilal Amin wrote: > Hi Everyone, > > Some days back I emailed on the group regarding the jitter in the sampling > clock of ADC. I have tried the phase modulation method for producing the > jitter. > I used the HP 8648B Signal generator for this experiment. I modulated the RF > wave (at 10 MHz)

Re: [time-nuts] need power trans. for HP3325

Didier Juges wrote: > Even though you may have to be careful about noise, and assuming the > operating voltages are not exotic, you can probably find an > off-the-shelf switching supply that will fit where the transformer and > linear supplies were, with lots of room to spare, and significantly

Re: [time-nuts] need power trans. for HP3325

Didier Juges wrote: > Dr Bruce Griffiths wrote: > >> Didier Juges wrote: >> >> >>> Even though you may have to be careful about noise, and assuming the >>> operating voltages are not exotic, you can probably find an >>> off

Re: [time-nuts] need power trans. for HP3325

Didier Juges wrote: > Dr Bruce Griffiths wrote: > >> Didier >> >> Try using a Murata BNX002 filter between the switching supply output and >> the linear regulator input. >> These should eliminate the High frequency noise (0.5MHz - 1GHz) from the >&

Re: [time-nuts] need power trans. for HP3325

Didier Juges wrote: > They are not, but system designers, as far as I can tell, have overcome > this problem by providing local filtering/decoupling/regulation at the > most sensitive points and therefore do not require the entire power > budget to a system to be low noise. > > Most of our

Re: [time-nuts] Sensing pendulum position, speed, or height

Hal Murray wrote: > How do modern pendulum clock geeks measure what their pendulum is doing? I'm > picturing a magnet on the bottom of the pendulum and a coil or hall effect > sensor. > > > > > A variation on this would be optical as in CD reader technology. Put a > pattern on the bottom of th

Re: [time-nuts] Sensing pendulum position, speed, or height

Hal Murray wrot > The hardware used for bar code scanners might be a useful starting place. I > assume you would have to hack the firmware/whatever to output time/position > info rather than bar code data. > > > > My initial thought was that you would put one read head directly under the > midd

[time-nuts] Ultra low phase noise floor measurement system for RF devices.

Anyone contemplating measuring ultra low phase noise devices should read the following paper on the interferometric method as applied to phase noise measurement. http://arxi

Re: [time-nuts] Ultra low phase noise floor measurement system for RF devices.

[EMAIL PROTECTED] wrote: > > In a message dated 3/29/2007 21:33:44 Pacific Daylight Time, > [EMAIL PROTECTED] writes: > > _http://arxiv.org/PS_cache/physics/pdf/0503/0503015.pdf_ > (http://arxiv.org/PS_cache/physics/pdf/0503/0503015.pdf) > > > Hi Bruce, > > Isn't a -200dBc/Hz floor below th

Re: [time-nuts] Ultra low phase noise floor measurement system forRF devices.

Mike Feher wrote: > Well, I must admit I did not read the referenced article, but, he is talking > about dBc, or relative to the carrier and not kT. So, if the carrier power > is high enough I suppose it could be done. Even suppose you could measure > it, what would it take to generate such a pure

[time-nuts] Ultra low noise amplifiers.

The following papers may be of some interest to anyone contemplating building a low noise low frequency (dc -100kHz) amplifier. Such an amplifier would be useful, for example, after a double balanced mixer in a conventional phase noise measurement system. http://arxiv.org/PS_cache/physics/pdf/050

Re: [time-nuts] Ultra low phase noise floor measurement system forRF devices.

> Mike > > It actually measures the additive phase noise of components > (amplifiers, splitters, transformers etc.). > Since it uses a cross correlation technique it can easily achieve a > noise floor below the thermal noise. > Cancellation of the carrier in the interferometer/bridge allows us

Re: [time-nuts] Ultra low phase noise floor measurement system for RF devices.

[EMAIL PROTECTED] wrote: > > In a message dated 3/30/2007 16:02:15 Pacific Daylight Time, > [EMAIL PROTECTED] writes: > > It does in fact measure below the thermal noise floor. > This is not too difficult as it uses a crosscorrelation technique. > > Bruce > > > > Hi Bruce, > > interesting h

Re: [time-nuts] Ultra low phase noise floor measurement system for RF devices.

Said > Actually I should have said -200dBc/Hz. > With a +13dBm carrier this corresponds to a noise voltage of 100pV/rtHz > across a 50 ohm resistor or a noise current of 2pA/rtHz flowing through it. > Even with a 1Hz noise bandwidth thats an rms fluctuation of about > 12,500,000 electrons. You h

Re: [time-nuts] Ultra low phase noise floor measurement system for RF devices.

[EMAIL PROTECTED] wrote: > > In a message dated 3/30/2007 19:14:31 Pacific Daylight Time, > [EMAIL PROTECTED] writes: > > With a +13dBm carrier this corresponds to a noise voltage of 100pV/rtHz > across a 50 ohm resistor or a noise current of 2pA/rtHz flowing through it. > > > > Hi Bruce,

Re: [time-nuts] phase noise and related stuff

John Miles wrote: > Hi, Enrico -- > > I think a lot of us already tracked down your (excellent) site based on a > couple of links to your papers that were mentioned on the list earlier. > Thanks for making that content available! These days, it seems that half of > Google's search results on any g

Re: [time-nuts] Ultra low phase noise floor measurement system for RF devices.

[EMAIL PROTECTED] wrote: > > In a message dated 3/30/2007 23:47:12 Pacific Daylight Time, > [EMAIL PROTECTED] writes: > > Thermal noise and other noise in each channel are statistically > independent and their product averages to zero. > The actual residual decreases as the number of spectr

Re: [time-nuts] phase noise and related stuff

John Ackermann N8UR wrote: > John Miles said the following on 03/31/2007 03:16 PM: > >> Yep, that's the one. It used to be linked from his measuringphasenoise.htm >> page but the link now points to something on his own f: drive, which is >> sadly inaccessible to the rest of us... >> > > Ye

Re: [time-nuts] Ultra low phase noise floor measurement system for RF devices.

[EMAIL PROTECTED] wrote: > Hi Magnus, > > > BTW: here in the US they also like to measure things in fractions, and body > part lengths for some unexplainable reason... Reasons I do hear are that SI > is too "difficult" for the average Joe to comprehend, and replacing road > signs > costs

Re: [time-nuts] Ultra low phase noise floor measurement system for RF devices.

Magnus Danielson wrote: > > I'm considering putting that new and shiny audio analyzer to some alternative > use that I bought at work. Preferences towards BNC, XLR or Banana-jacks > anyone? > :) > > I was just looking at the 3048 manuals the other night. Bumped into a new site > with HP manuals I

Re: [time-nuts] Ultra low phase noise floor measurement system for RF devices.

John Ackermann N8UR wrote: > Dr Bruce Griffiths said the following on 03/31/2007 08:24 PM: > > >> The second reason is somewhat spurious, other countries have converted >> from the imperial to the metric system without major difficulty or >> expense. It wasn

Re: [time-nuts] phase noise and related stuff

Magnus Danielson wrote: > > > Indeed. > > When I started doing webpages, Emacs was the tool and the Netscape beta had > just hit the streets. We had this Alta Vista search engine comming along which > was a cool Digital database demo. > > Yeah, I actually recall the times before Google. :-) We had

Re: [time-nuts] Ultra low phase noise floor measurement system for RF devices.

[EMAIL PROTECTED] wrote: > Hi Bruce, > > got it, thanks. > > But isn't a signal source typically single-ended, and has a 50 Ohm source > impedance which creates noise? > > Wouldn't we need a source with 1 Ohm source impedance even if the > measurement system is cross-correlated? > > Wou

Re: [time-nuts] Ultra low phase noise floor measurement system for RF devices.

Magnus Danielson wrote: > In the article that was recently referred to, it was not a measurement rig for > oscillators but for transfer components, such as gain-stages, phase shifters > etc. and the approach is different then, since you do have the signal prior to > being dirtyfied. Thus, the inter

Re: [time-nuts] Standards for units

David Dameron wrote: > Hi all, > I just realized that a meter is defined by the speed of light., see > http://physics.nist.gov/cuu/Units/meter.html > It is only to 9 significant digits, so if the speed of light (in some > controlled environment) is measured more precisely than this, the meter and

Re: [time-nuts] Standards for units

David Dameron wrote: > Hi all, > I just realized that a meter is defined by the speed of light., see > http://physics.nist.gov/cuu/Units/meter.html > It is only to 9 significant digits, so if the speed of light (in some > controlled environment) is measured more precisely than this, the meter and

Re: [time-nuts] Standards for units

David Dameron wrote: > Hi all, > I just realized that a meter is defined by the speed of light., see > http://physics.nist.gov/cuu/Units/meter.html > It is only to 9 significant digits, so if the speed of light (in some > controlled environment) is measured more precisely than this, the meter and

Re: [time-nuts] Lucent RFTG-m-XO ...

geo wrote: > Hi Jason, > > perhaps i am the only "german", currently available. My english is not good > but i hope, it's less pain for you to read my "english" than to read the > german text ;-) > > Best regards > > Martin Bertges > > > > Description of Lucent RFTG-m-XO GPS frequency standard > ve

Re: [time-nuts] Standards for units

Chuck Harris wrote: > Chuck Harris wrote: > >> David Dameron wrote: >> >>> Hi all, >>> I just realized that a meter is defined by the speed of light., see >>> http://physics.nist.gov/cuu/Units/meter.html >>> It is only to 9 significant digits, so if the speed of light (in some >>> controll

Re: [time-nuts] Standards for units

James Cloos wrote: >> "David" == David Dameron <[EMAIL PROTECTED]> writes: >> > > David> (I was taught that 1 meter was 39.37 inches, to define the > David> inch, but now I see more of 1 inch = 2.54 cm, as someone just > David> referred to.) > > That was the old inch. It was c

Re: [time-nuts] Standards for units

Palfreyman, Jim L wrote: > Are there actually US people on this list who actually continue to > advocate the use of non-metric units in their country? Speak up! > > Well the USA ever go metric? > > As an Australian, why would I care, you may ask? > > Well because of the dominance of the US market,

Re: [time-nuts] NavSync CW46 Module

Darrell Robinson wrote: > In the January 2007 issue of Microwaves & RF magazine I see a paragraph or > two about a GPS disciplined frequency source. > The company is NavSync and the module is part number CW46. The stated price > is $176 if you are buying 1000 of them. > I don't know what one uni

Re: [time-nuts] GPS disciplined oscillators - how not to do it.

Bob Paddock wrote: > On Tuesday 03 April 2007 21:48, Dr Bruce Griffiths wrote: > >> An Australian Electronics magazine recently published a circuit for a >> GPS disciplined crystal oscillator. >> This particular implementation is the worst I've ever seen. >&g

Re: [time-nuts] GPS disciplined oscillators - how not to do it.

Peter Vince wrote: > It's a shame the magazine article got it so wrong, but I can well > imagine how an enthusiastic amateur, without the collective knowledge > of our little group, might, with all good intentions, make such a > mess of the design. > > I wonder if Bruce, or one of the other expe

Re: [time-nuts] GPS ADEV?

Tom Van Baak wrote: > John, > > I like the questions you ask. Here's an updated plot: > > http://www.leapsecond.com/pages/3gps/gps-adev.gif > > Note that the tau 1 second Allan deviation is essentially > the standard deviation of the sawtooth: in the graph the > VP is about 55 ns, CNS about 15 ns,

Re: [time-nuts] Looking for Wavecrest Visi

[EMAIL PROTECTED] wrote: > > In a message dated 4/7/2007 04:08:20 Pacific Daylight Time, > [EMAIL PROTECTED] writes: > > > The Wavecrests are wonderful tools, but they address a different problem > than > what normal time-nuts usually care about, so they are not a given perfect > counter fo

Re: [time-nuts] Looking for Wavecrest Visi

Said Some of the highest resolution techniques for comparing 2 10MHz sources are: 1) Use a Quartzlock A7-MX - resolution 5E-14/tau equivalent to 50 fs at 1 sec. 2) Use the JPL technique: Measure the beat frequency between the 2 oscillators (offset one oscillator by 1Hz using an offset generato

Re: [time-nuts] Looking for Wavecrest Visi

[EMAIL PROTECTED] wrote: > > > Hi Bruce, > > My math is essentially their reference [4, p.26], and I did state that I > don't know the exact interpolator, trigger, and frequency-dependent noise > functions of the Wavecrest. > > DTS-2075 is superior to the SR-620 and 53132A in time interva

Re: [time-nuts] Looking for Wavecrest Visi

[EMAIL PROTECTED] wrote: > Hi Bruce, > > again, I did say in my original post that my math only works if their noise > is Gaussian, and that I did not know if it was. > > Also, please note that they do claim 25ps Accuracy , and 800 femtoseconds > Hardware resolution, not the other way aroun

Re: [time-nuts] Looking for Wavecrest Visi

[EMAIL PROTECTED] wrot > I am trying to set up a Win98 machine with GPIB since I bought a quite old > version of Visi from Wavecrest that runs only on Win98. > That's what usually happens with 16 bit Windows95/98 applications. 32 bit applications usually run on Win2K/XP/98 without difficulty.

Re: [time-nuts] Looking for Wavecrest Visi

[EMAIL PROTECTED] wrote: > > In a message dated 4/8/2007 16:49:00 Pacific Daylight Time, > [EMAIL PROTECTED] writes: > > Since Wavecrest, 53132A etc have no specifications for the effect of the > input circuit noise with a finite slew rate input, the only way to make > a more precise compa

[time-nuts] Gate propagation delay jitter

The attached table of logic gate propagation delay jitter should prove somewhat challenging to verify with a time interval counter or similar device. In fact devising any method of verifying these figures will be somewhat problematic. However it could be done using by looking at the change in th

Re: [time-nuts] Gate propagation delay jitter

David Andersen wrote: > Dr Bruce Griffiths wrote: > >> The attached table of logic gate propagation delay jitter should prove >> somewhat challenging to verify with a time interval counter or similar >> device. >> In fact devising any method of verifying

Re: [time-nuts] Looking for Wavecrest Visi

John Ackermann N8UR wrote: > John Ackermann N8UR said the following on 04/09/2007 08:40 AM: > > >> I recently built 6 nominally 10 foot GPS antenna cables out of LMR-400. >> They all had N connectors on one end, but the opposite ends were two >> each of N, BNC, and TNC, which made measurement i

Re: [time-nuts] GPS: ADEV or MDEV?

Brooks Shera wrote: > In view of recent interest in the Allan Deviation of GPS-based 1 pps time, > it should be mentioned that the calculation of ADEV is based on a > statistical model which is not completely appropriate for noise sources > present in GPS signals and their decoding hardware/softwar

Re: [time-nuts] GPS: ADEV or MDEV?

Poul-Henning Kamp wrote: > In message <[EMAIL PROTECTED]>, "Brooks Shera" writes: > > >> The impact of time averaging to suppress white phase noise is illustrated >> by a new plot TVB has created and placed on his website >> http://www.leapsecond.com/pages/3gps/gps-adev.gif. >> >> These reveali

Re: [time-nuts] Gate propagation delay jitter

Ulrich Bangert wrote: > Bruce, > > the following is part of a discussion in comp.arch.fpga: > > > . > Hi, > I would like to know what are the common methods of introducing > delays as low as 10ps between two outputs in an FP

Re: [time-nuts] Gate propagation delay jitter

Enrico Rubiola wrote: > My friends, if you worry about jitter there is a trick: > synchronize the signat to the clock with a D-type flip flop, > just at the output. > Maybe too trivial for you. > E. > > > Enrico Rubiola > professor of electronics > > web: http://rubiola.org > e-mail: [EMAIL

Re: [time-nuts] Gate propagation delay jitter

Hal Murray wrote: >> I would like to know what are the common methods of introducing >> delays as low as 10ps between two outputs in an FPGA. I do not >> > > I'd try to make the delays within the FPGA the same and then tweak the > external trace lengths. At that level of detail, you will h

Re: [time-nuts] GPS: ADEV or MDEV?

Hal Murray wrote: > [context is avoiding hanging bridges] > > >> Ovenize it to control the sawtooth frequency? >> Temperature controlled oscillator! :-) >> Should be fairly simple to acheive, really just a FLL. >> > > I was wondering about that a while ago. Is the basic idea feasible? > >

Re: [time-nuts] Gate propagation delay jitter

Magnus Danielson wrote: > From: Enrico Rubiola <[EMAIL PROTECTED]> > Subject: Re: [time-nuts] Gate propagation delay jitter > Date: Wed, 11 Apr 2007 00:14:01 +0200 > Message-ID: <[EMAIL PROTECTED]> > > Enrico, > > >>> Then we would need to know/measure the jitter of the retiming >>> flipflop.

Re: [time-nuts] Gate propagation delay jitter

[EMAIL PROTECTED] wrote: > > In a message dated 4/10/2007 14:33:17 Pacific Daylight Time, > [EMAIL PROTECTED] writes: > > Yes ground bounce can play havoc with the effective switching thresholds. > One would expect this effect to be much worse with single ended clocks. > > Bruce > > > > Hi B

Re: [time-nuts] Gate propagation delay jitter

[EMAIL PROTECTED] wrote: > > In a message dated 4/10/2007 14:28:11 Pacific Daylight Time, > [EMAIL PROTECTED] writes: > > Then we would need to know/measure the jitter of the retiming flipflop. > There appears to be little definitive published data on the jitter of > various logic gates and

Re: [time-nuts] Setting Osc Frequencies

Hal Murray wrote: >> And Hal- what about the pcb layout for Bruce's 74CX version? Had time >> to look at it yet? >> > > It fell through the cracks when I got interested in something else. > > Is anybody really interested in that board? If so, please send me a > reminder about the schematic.

Re: [time-nuts] Setting Osc Frequencies

VK3YV wrote: Hi Bruce, I for one would like to get the completed circuit seeing as I started the whole thing off and was just getting ready to maybe do a copy of the HP unit. Regards DonVK3YV. Don AD9901 version attached. It needs another opamp to be added to allow the scale and off

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