Re: [time-nuts] Phase-noise through mixer?

Mixers also have the curious phenomenon of non-reciprocity On 10/17/2016 4:13 PM, Bob Camp wrote: Hi Simple answer is yes. More complex answer gets into things like the noise of the mixer (not just it’s floor), the levels of the signals, noise being coherent rather than non-coherent, AM <->

Re: [time-nuts] notch filter for close in phase noise measurement

On 10/2/2016 12:56 AM, Adrian Rus wrote: Hello list, For those of you interested in phase noise measurement without using fancy/dedicated gear, There is no free lunch here. The crystal has its own intrinsic flicker of frequency noise. You cannot measure below this noise floor. The

Re: [time-nuts] Vintage Quartz Crystal Manufacturing

On 9/25/2016 6:53 AM, Bob Camp wrote: Hi If you dropped in to a crystal manufacturing plant at any point over the next 30 years after that film was made, the styles of dress had changed. The crystal holders had changed. Most of the processes were still the same and some of the gear was

Re: [time-nuts] HP 5065A questions

On 9/25/2016 6:42 PM, Skip Withrow wrote: 1. What the heck is rubidium cell flooding, and how does the TEC in the 5065A fix this problem? None of the -many- rubidium oscillators that I have been inside before has a TEC, and I have never seen the subject addressed. The manual suggests that it

[time-nuts] Hobbyist grade or homebrew temperature testing chamber?

As we all know, step #1 in making a clock is NOT to build a thermometer :-) I thought I would check the brain trust here to see if anyone has seen a hobbyist grade temperature testing chamber or kit or homebrew design. I have some crystals, oscillators, and other electronics I would like to

Re: [time-nuts] DIY VNA design

On 8/21/2016 3:59 PM, Dr. David Kirkby (Kirkby Microwave Ltd) wrote: That said, I don't know why the author is using directional couplers. A bridge is much wider bandwidth. It is more lossy though. In general, a resistive bridge will always require a transformer/180 degree

Re: [time-nuts] DIY VNA design

Another great posting, Attila. When I was with Agilent, we looked at all kinds of simplified network analyzer architectures, and I would have to say the author is really well informed. One issue he doesn't seem to be aware of is that the ADL5801, when driven single ended, has some quirks below

Re: [time-nuts] State of the art of crystal oscillator measurements

On 8/11/2016 3:47 PM, John Miles wrote: Right, I'm speaking specifically of L(f). The device being driven by the oscillator doesn't care about the NF of the driver stage, only what a PN analyzer would measure at the output jack. For any 50-ohm source, the practical L(f) floor is -177

Re: [time-nuts] State of the art of crystal oscillator measurements

Zo doesn't matter for these purposes. dBm works just as well for 75 ohm systems. On 8/11/2016 1:22 PM, John Miles wrote: Remember that L(f) is expressed in dBc/Hz, not dBm/Hz. If it were dBm/Hz, then kT would be the limit. But in dBc/Hz terms, the limit is 177 + the DUT's output power in

Re: [time-nuts] State of the art of crystal oscillator measurements

On 8/11/2016 5:01 AM, Mike Feher wrote: This may be a naive question, but, how can you achieve results that are so close to, and sometimes at further out are below kT? Thanks & 73 - Mike Mike B. Feher, EOZ Inc. kT per see is not the relevant parameter. It is the ratio between kT and

Re: [time-nuts] Oscillator Phase Noise: A 50-Year Review

On 8/5/2016 12:47 PM, Tom Van Baak wrote: Here's a new article, on IEEE's site (and this one's free): "Oscillator Phase Noise: A 50-Year Review", by David B. Leeson http://ieeexplore.ieee.org/stamp/stamp.jsp?arnumber=7464875 It has always irked me that no credit was given to Edson's

Re: [time-nuts] Effect of EFC noise on phase noise

Around 35 years ago, I worked with the guys who designed and manufactured the 10811. There are a couple of things here that don't add up, subject to remembering stuff from a LONG time ago: 1. Back in those days at least, there were vendors who supposedly specialized in providing low noise

Re: [time-nuts] Precision DACs

On 7/25/2016 10:42 PM, Scott Stobbe wrote: dramatically different due to glitching on code transition. That being said, they are kept separate not to confuse sources of error. FWIW: The 5071A has a "home brew" DDS that was designed by the late (and great) Robin Giffard. He used what he

Re: [time-nuts] NCOCXO anyone?

On 7/24/2016 6:44 AM, James Flynn wrote: Hal Murray writes: Has anybody put the DAC and all of the analog stuff inside the oven? Seems like an obvious idea so somebody has probably patented it. I am using a 5 MHz custom built design which has everything inside the outer oven

Re: [time-nuts] NCOCXO anyone?

On 7/22/2016 10:15 AM, David wrote: It is too bad voltage control of an oscillator cannot be made ratiometric. Or can it? I have never heard of such a thing. That would remove some of the demands on a low drift reference. That's what we tried to do with the E1938A. A multiplying DAC

Re: [time-nuts] NCOCXO anyone?

On 7/22/2016 2:22 AM, Attila Kinali wrote: Hoi Rick, On Thu, 21 Jul 2016 18:47:24 -0700 "Richard (Rick) Karlquist" <rich...@karlquist.com> wrote: Also in 1996, phase microsteppers were already legacy technology and didn't have a good reputation for spectral purity. Ano

Re: [time-nuts] NCOCXO anyone?

On 7/21/2016 4:56 PM, Nick Sayer via time-nuts wrote: Oh my. That’s a bit more than I was originally considering… What I had in mind was adding a DAC front end to an OCXO so that you could tune the EFC with serial commands rather than analog and calling that a product. 20 years ago when

Re: [time-nuts] Switching transistors, current sources, nonidealties and noise

I vaguely remember seeing designs where a through hole transistor like a 2N5179 had a ferrite bead slipped over the base to keep it stable. Although this works, it degrades the performance of the transistor. I prefer to put a resistor in series with the collector instead of the base. Since the

Re: [time-nuts] buying a time interval counter

On 6/29/2016 10:20 AM, Brooke Clarke wrote: PS Stanford Research is a company founded by physicists and makes some really high quality stuff. In fact some of the products HP/Agilent/Keysight sells are repackaged SR instruments. http://www.prc68.com/I/TandFTE.shtml#SR620 In the old days,

Re: [time-nuts] buying a time interval counter

On 6/29/2016 9:22 AM, Dr. David Kirkby (Kirkby Microwave Ltd) wrote: There is also a Keysight 53230A with a slightly better (20 ps vs 25 ps) single shot resolution. It looks more modern, but I don't know how well they compare. Dave. The 53230A does not offer a 10811 option, but instead

Re: [time-nuts] A little telegraph history, slightly off topic

More off topic: I saw on the history channel a story about a British radio installation in France (IIRC) that was taken over by the Germans, who proceeded to masquerade as British operators, hoping to gather intelligence. The British became suspicious and someone got the bright to append "HH"

Re: [time-nuts] that's really awesome

Probably not necessary on this reflector, but often needed on other reflectors I read: If you are making a legitimate post that is not spam, don't use "teaser" subject lines, etc. that mimic spam messages. Don't post tinyURL links either, no telling what those are. Shouldn't have to say this,

Re: [time-nuts] ADCs for phase noise measurement

On 6/11/2016 6:33 AM, Attila Kinali wrote: Hoi Rick, use a small uC board to interface with the PC. Saving the samples in a wav file and using one of the many FFT tools shouldn't be a problem. This gets even better. The free Pscope software comes with FFT. I don't even need to fool with

Re: [time-nuts] ADCs for phase noise measurement

On 6/11/2016 6:33 AM, Attila Kinali wrote: Hoi Rick, I don't know which phase noise measurement sturcture you are going to use exactly or what your goals are, so I am guessing here a little bit... I'm interested in at least 10-100 Hz offset, 1-1000 Hz offset would be a bonus. Thus audio is

Re: [time-nuts] windows for FFT measurements of phase noise

I remember cobbling together a home brew phase noise system 35 years ago using an HP3582 FFT analyzer. It had several available windows: IIRC: flat top, rectangular, and hamming (hanning? I can never get them straight). Basically, if you are looking for spurs, you need to use the flat top.

Re: [time-nuts] Divide by 3

I remember when we first got a prototype 10816 Mini-Rubidium standard working. We put in on of those old paper strip chart recorders (this was circa 1981). We were pretty cocky about how it went straight down the page. You couldn't do that with quartz. When we came back the next day, you

Re: [time-nuts] Divide by 3

On 6/8/2016 9:59 AM, Charles Steinmetz wrote: You can achieve substantially lower jitter (phase noise) with a regenerative divider, which also allows you to divide by 3/2 for a 10MHz output. I've built several like that, and they work extremely well. When I was at Agilent, they developed

Re: [time-nuts] How can I generate a very clean 1 W signal @ 116 MHz ?

On 5/31/2016 3:30 AM, Dr. David Kirkby (Kirkby Microwave Ltd) wrote: Please excuse my ignorance, but how would one lock a 116 MHz 5th overtone crystal oscillator to 10 MHz with no difficulty? Do you have a circuit you share that would give low phase noise, and if so how low? If you

Re: [time-nuts] How can I generate a very clean 1 W signal @ 116 MHz ?

I'm really surprised at all the complicated solutions posted here. A 116 MHz crystal oscillator is not rocket science. Croven Crystals will sell you a custom resonator. The whole circuit is like a dozen components. Rick N6RK ___ time-nuts mailing

Re: [time-nuts] How can I generate a very clean 1 W signal @ 116 MHz ?

On 5/30/2016 4:06 AM, Dr. David Kirkby (Kirkby Microwave Ltd) wrote: I was thinking about designing a 2 m (144-146 MHz) ->HF (28-30 MHz) transverter, using a 116 MHz local oscillator feeding a level 30 mixer. 116 + 28 = 144 116 + 30 = 146 I'm wondering what's the best way to generate 116 MHz

[time-nuts] Wenzel BP-1000 phase noise measurement system

Does anyone have any experience with this system? Rick Karlquist ___ 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] Mystery hp Ovens For Sale

Len Cutler proudly displayed an HP106 in his office. It was one of the examples of Len's philosophy of making the best possible design rather than a "good enough" design. I never heard what happened to it when he passed away. Rick ___ time-nuts

Re: [time-nuts] Get together at IMS?

I'll be there all day Wednesday. I'll try to meet you guys at 5 PM. Rick Karlquist N6RK On 5/22/2016 9:06 AM, Bernd Neubig wrote: Agreed! See you on Wed at 5.00pm at Booth 714 (Dynamic Engineers) -Ursprüngliche Nachricht- Von: time-nuts [mailto:time-nuts-boun...@febo.com] Im Auftrag

Re: [time-nuts] HP5071

On 5/21/2016 11:25 AM, Attila Kinali wrote: I'd give a lot to read the design documents of the 5071. There must be a lot of knowhow and techniques in them. Read papers by me and my colleagues at the 1992 Frequency Control Symposium. There is nothing else in the public domain. What

Re: [time-nuts] GENIUS by Stephen Hawking (PBS TV),

On 5/21/2016 8:37 AM, ws at Yahoo via time-nuts wrote: How would one go about to prove beyond a doubt in that experiment that 18ns of phase shift in 24 hrs was truly caused by freq offset due to Relativity and not by some other combination of environment and handling issues that effected phase

Re: [time-nuts] High rate, high precision/accuracy time interval counter methods

HP/Agilent/Keysight laser interferometers measure at the kind of rates you are talking about and (last time I heard) could divide an interference fringe down to 1/512 of a wavelength. As you say, they definitely use an ASIC with a ring oscillator. Perhaps there is some way you could repurpose

Re: [time-nuts] HP OCXO warmup graphs

On 4/23/2016 6:27 PM, Bob Camp wrote: Hi The 5334 spanned the era when the 10811 was being introduced. I’ve never been able to sort out exactly *what* was in each version as shipped and what got swapped around by various techs over the years. I always *thought* the 10811 was standard for the

Re: [time-nuts] HP 5360A History?

On 4/13/2016 12:28 PM, Pete Lancashire wrote: that even with a $10K price they sold, either Bill or Dave were advised to cancel the project due to its growing cost and complexity but decided to keep it going in that HP would learn about designing with logic. I have an internal HP logic design

Re: [time-nuts] HP 5360A History?

This product came out in the early '70's when I was working for Boeing. The company bought several and they were very popular. This was an amazing advance for the time, to be able to measure short term stability so easily. This was before HPIB, so you couldn't easily connect a counter to a

Re: [time-nuts] Where does the source time for GPS come from?

On 4/12/2016 3:16 PM, Michael Wouters wrote: evaluations (for accuracy) to finally get its best estimate of what one second is. Each participating lab is then told what the difference between its clock and UTC is. USNO participates in UTC and keeps within tens of ns of UTC. It might also

Re: [time-nuts] high rev isolation amps

On 3/30/2016 8:18 AM, Tim Shoppa wrote: There's a real beauty to many of the NIST designs - using topology and jellybean parts to achieve the performance, rather than selected devices. Tim N3QE If only this were true. Authors at NIST have consistently told me that the conditions of

Re: [time-nuts] high rev isolation amps

Nothing has come to my attention in the last 35 years that is superior for buffer amplifiers to the simple cascade of grounded base transistors as described by numerous NBS/NIST papers. The chain usually starts with a common emitter (with emitter degeneration resistor), which is an even older NBS

Re: [time-nuts] Spectrum Analyzer Specifications

exotic. Bob On Mar 24, 2016, at 12:25 AM, Richard (Rick) Karlquist <rich...@karlquist.com> wrote: On 3/23/2016 3:56 PM, Bob Camp wrote: and standard covered. If you want to do spurs, spend $40 and build a phase noise test set that will drive the sound card on your PC. Lots of c

Re: [time-nuts] Spectrum Analyzer Specifications

On 3/23/2016 3:56 PM, Bob Camp wrote: and standard covered. If you want to do spurs, spend $40 and build a phase noise test set that will drive the sound card on your PC. Lots of choices …. Bob Any documentation on this $40 phase noise test set? Rick N6RK

Re: [time-nuts] When does NIST change to DST?

On 3/13/2016 10:39 AM, Nick Sayer via time-nuts wrote: Our WWVB clock switched way, way early last night - like 20:00 or so (PST). but that clock hasn’t exhibited any whacky behavior as long as I can remember. Same here with my clock. Rick ___

Re: [time-nuts] quartz thermometers

Does anyone have a documented way to do this? I asked the original designers of the 10811 (Burgoon and Wilson) about this a few years ago and they couldn't remember what the circuit mods were. I got hold of their lab notebooks and it wasn't in there either. What I remember them telling me 35

Re: [time-nuts] PLL book 3rd edition

On 3/8/2016 10:11 AM, jimlux wrote: Or is subject to export controls because of the specific application. While you could probably "generalize" it to get out from under export controls, that's a lot of work. Ulrich and Rick raise interesting points: The people who really know about this

Re: [time-nuts] PLL book 3rd edition

On 3/8/2016 3:18 AM, ka2...@aol.com wrote: Good Morning, technically you are correct, most buy what they find and live with a compromise. But companies like mine, R, test equipment , need superior performance and many parts which we need, we have made by foundries. Numerically controlled

Re: [time-nuts] PLL book 3rd edition

I know for me, I mainly use the "synthesizer on a chip" IC's from Analog Devices/Hittite and National. Their data sheets and ap notes serve as the "textbook". I'm not sure there will be much call going forward for a book on fundamentals that explains how to design synthesizers from first

Re: [time-nuts] HP 10544A Repair

On 3/1/2016 4:13 AM, Bob Camp wrote: Is it worth getting it super close? Probably not without a temperature test setup. Bob Right. It is entirely possible that if you did a temperature test in an environmental chamber, you would find that you could get a better tempco by adjusting oven

Re: [time-nuts] HP 10544A Repair

On 2/28/2016 7:01 AM, Bob Camp wrote: Hi It’s not an electrical issue as much as a heat issue …. Before you start, consider that you will be doing something like: Move trimmer 1 turn CW Wait 10 minutes read frequency Move trimmer 1 turn CW wait / read Move trimer 1/2 turn CCW wait / read

Re: [time-nuts] HP 10544A Repair

If you replaced the thermistor with an exact replacement, then you shouldn't need to change the pot. If you didn't replace the thermistor with an exact replacement, then you should carefully measure the resistance of the pot as you found it. (I hope you did not fool with it already.) From the

Re: [time-nuts] HP Reliability

On 2/14/2016 11:20 AM, William H. Fite wrote: They don't wonder; they know very well. But they're stuck. Consider oscilloscopes. Why pay for a Keysight or Tectronix or LeCroy or, God forbid, a Rohde & Schwarz when, for the vast majority of applications, a Rigol will give you everything you

Re: [time-nuts] HP Reliability

A few clarifications: Before 1999, HP had a Medical Division that made equipment you saw in hospitals and a Scientific Instrument Division that made chemical analysis equipment used in medical laboratories (and also other laboratories). IIRC, both began as acquisitions. The Agilent spin off in

Re: [time-nuts] Calibration procedures - what is normal?

On 2/12/2016 12:14 PM, Joseph Gray wrote: I sent my HP 3457A in for cal. I should be getting it back next week. I won't mention where I sent it, but it wasn't Keysight (I don't like that name). I recently changed the SRAM battery and purposely did not I left Agilent just before the split, but

Re: [time-nuts] HP Equipment Running Hot as Heck...

Vintage HP equipment often had HP made power transformers, which ran all the time whether the equipment was on or off. The core loss while idling could be fairly high. The core was usually just below saturation, so that if the power switch was on 100V, it would really get hot. There was some

Re: [time-nuts] HP5370B & HP5345B Front-End IC Redesign Effort

On 1/22/2016 2:14 PM, Mathew Breton wrote: I was gifted an HP 5370B with the usual problem: front-end problems, probably due to overstress. It is currently up and running again with a set of 5345A series A3/A4 boards as I wasn't able to get a cheap pair of 5088-706x hybrid ICs. This sounds

Re: [time-nuts] what is acceptable harmonic content & level for a 10Mhz standard?

On 1/26/2016 11:52 AM, walter shawlee 2 wrote: I have been working on a compact portable 10Mhz bench standard using both an FE FE5680A Rb oscillator and an Oscilloquartz ovenized It is important for a 10 MHz source to launch a pure sine wave and also to have an accurate 50 ohm impedance at

Re: [time-nuts] low noise multiplication to 100 MHz

It is interesting that the HP8662A multiplies 10 MHz to 640 MHz, in steps of 2X. But there is a crystal filter at 80 MHz to clean up the wideband noise of the 10811. In the 11729, they filter the 640 MHz from the 8662 with a SAW filter, again to eliminate multiplied up wideband noise. It's

Re: [time-nuts] New Member + Basic Questions

On 1/14/2016 12:35 PM, Nathan Johnson wrote: What does the group think of the HP 8660? Just scored a broken one too cheap to pass up. I know it's not gonna be the last signal generator I buy, but for under $100 shipped it should be an interesting project. Nathan KK4REY When I worked at HP,

Re: [time-nuts] Divider circuit for Rubidium Standard

for the multistage zero crossing detectors discussed on this forum many times. Rick On 1/10/2016 2:24 AM, Attila Kinali wrote: Hi Rick, On Sat, 9 Jan 2016 14:45:43 -0800 "Richard (Rick) Karlquist" <rich...@karlquist.com> wrote: This circuit is very similar to one that was champione

Re: [time-nuts] DMTD - analog multiplier vs. diode mixer ?

Phase frequency detectors (starting with the legendary MC4044) being made out of flip flops, had metastability and/or race conditions. Motorola showed a block diagram made of gates, as if it were combinatorial logic, but because of the feedback, it is actually a state machine, as described in

Re: [time-nuts] Divider circuit for Rubidium Standard

On 1/9/2016 12:44 PM, Attila Kinali wrote: The purpose of the input circuit is to convert the RF input signal into a low-jitter square wave that can drive the PIC clock input. The circuit is closely based on the one published by Wenzel at http://www.wenzel.com/documents/waveform.html, with

Re: [time-nuts] DMTD - analog multiplier vs. diode mixer ?

On 1/7/2016 3:11 PM, Bob Camp wrote: Hi If your intention is to run a mixer with saturated inputs …. just run an X-OR gate. It will handle the high level signals much better than an over-driven analog part. Bob If you look at the schematic of an XOR gate IC and compare it to the

Re: [time-nuts] DMTD - analog multiplier vs. diode mixer ?

On 1/7/2016 4:35 AM, Attila Kinali wrote: How about using the Gilbert Cell as "digital" mixer, ie driving the currents hard from one branch to the other and replacing the current sources by resistors? How much would that improve the noise? Would it be still much worse than the diode mixer?

Re: [time-nuts] DMTD - analog multiplier vs. diode mixer ?

On 1/5/2016 12:07 PM, Bruce Griffiths wrote: The noise of such Gilbert cell based analog multipliers far exceeds that of the traditional mixer. Bruce Read Gilbert's paper or Gray and Meyers analog IC textbook and you will see that the whole theory of operation of these depends on keeping

Re: [time-nuts] Phase noise from Allan Deviation ?

On 12/13/2015 7:15 PM, Tom McDermott wrote: It brings up a question: Is it possible to estimate the phase noise of that internal crystal from the ADEV measurements? There are a bunch of papers that go the other way: from Phase Noise to Adev. Searching brings up only one paper that goes

Re: [time-nuts] GPSDO and oscillator steering - EFC vs DDS schemes?

It's been 20 years since I presented that paper in San Francisco at FCS and I had just about forgotten about it. It is flattering to realize that people are still reading it now. It might be useful for the discussion here if I explained why I wrote the paper. We had recently completed the

Re: [time-nuts] Phase microstepper designs?

On 12/9/2015 2:26 AM, Attila Kinali wrote: Moin, I just tried to figure out how phase microsteppers are usually build, but, beside the time-nuts discussion from 10 years ago and US patents US4358741 and US4417352 my search turned out empty. I am pretty sure that I used the wrong search terms

Re: [time-nuts] modern electronics education/jobs (was:

On 11/12/2015 1:01 PM, William Schrempp wrote: has failed. I hear old machinists complaining about new machinists who can't drill a hole if the drill-press isn't computer-controlled. And in my work, nurse education, I see students who can't be bothered to learn how to take a manual

Re: [time-nuts] Time syncing WiFi routers using FM radio

On 11/12/2015 12:04 AM, Hal Murray wrote: I think it was HP that measured the signal in the Silicon Valley area. NBS published and distributed the offset. Does anybody remember that booklet? Did I get the story reasonably accurate? When I was hired by HP in 1979, my new boss (who was

Re: [time-nuts] Low noise quartz crystal oscillator by Bruce Griffiths

Driscoll wrote a lot about oscillators over the years. I couldn't find anything specific to discontinuous operation. Do you have a titel of a paper related to this? What Driscoll was talking about was self limiting in a transistor. That is discontinuous operation, although Driscoll doesn't

Re: [time-nuts] Low noise quartz crystal oscillator by Bruce Griffiths

On 10/27/2015 10:11 PM, Bruce Griffiths wrote: The answer to this conundrum is surely that the equation for PN doesn't apply directly in this case for offset frequencies outside the crystal bandwidth. The Crystal actually bandpass filters the signal and PN noise generated by oscillator. For

Re: [time-nuts] Low noise quartz crystal oscillator by Bruce Griffiths

Do you have a specific URL for "hacking oscillators"? I can't find it on Rubiola's web site. Rick On 10/28/2015 1:32 PM, Gerhard Hoffmann wrote: Am 28.10.2015 um 19:22 schrieb KA2WEU--- via time-nuts: This oscillator seems to have been more a frequency standard then a noise standard. Today's

Re: [time-nuts] Low noise quartz crystal oscillator by Bruce Griffiths

On 10/28/2015 10:38 AM, Hal Murray wrote: rich...@karlquist.com said: The 2N5179 in the 10811 is selected for minimum beta and Ft at 20 mA, which is the start up condition due to the ALC being at full gain. It has a special HP part number, so you wouldn't know this just looking at the parts

Re: [time-nuts] Low noise quartz crystal oscillator by Bruce Griffiths

On 10/26/2015 9:15 PM, Bruce Griffiths wrote: The 10811A ocxo uses an oscillator of this type albeit with a lower crystal current, an overtone crystal. However the output stages spoil the PN floor..Cascaded transformer coupled CB stages are somewhat quieter. Bruce That's right. Burgoon

Re: [time-nuts] Low noise quartz crystal oscillator by Bruce Griffiths

The oscillator transistor and buffer amplifier are basically the same as the HP 10811, except for the absence of mode suppressors. The difference here is that the oscillator self limits in the oscillator transistor, whereas the 10811 has ALC. The discontinuous operation of the transistor, as

Re: [time-nuts] 10811 unsoldered fuse

The thermal fuse plugs into pin sockets. It cannot be soldered for the obvious reason that the solder would melt it...at 109 degrees as it is marked. My suggestion would be to jumper it out of the circuit. Rick Karlquist N6RK On 10/19/2015 12:31 PM, Dimitri.p wrote: How common is it to find

Re: [time-nuts] HP Panel colors

There used to be a color at HP called mint gray FWIW. Rick On 8/13/2015 1:58 AM, tim...@timeok.it wrote: I am interested in knowing the exact name or number of the colors used by HP for the HP5065A front panels. ___ time-nuts mailing list --

Re: [time-nuts] how to find low noise transistors

OTOH, the other cure for high base spreading resistance is to simply parallel multiple devices. This avoids the bad side effects you mention. The other key noise parameter in a BJT is RF current gain, and this cannot be cured by any circuit design tricks. Rick Karlquist N6RK On 7/23/2015 8:29

Re: [time-nuts] how to find low noise transistors

On 7/24/2015 11:58 AM, Brooke Clarke wrote: Hi Charles: Does hFE (DC) have much relevance to this? Would hfe (AC) be the important one? Only insofar as DC current gain is an upper bound on AC current gain. If your operating frequency is less than f-sub-t divided by beta, then DC current

Re: [time-nuts] how to find low noise transistors

On 7/20/2015 8:12 AM, Charles Steinmetz wrote: Rick wrote: Base spreading resistance can be overcome by using a sufficiently high source impedance This sounds like the all-too-common noise figure fallacy (increasing input impedance to get a lower NF). All this does is raise the source

Re: [time-nuts] how to find low noise transistors

On 7/18/2015 2:16 AM, Attila Kinali wrote: I always wonder how you figure out whether a transistor is low noise or not. What part of the datasheet hints at which transistors have low noise and which have not? Even if it's just try and measure, how do you find good candidates to measure?

Re: [time-nuts] Close in phase noise of microwave VCOs

On 6/20/2015 6:25 AM, Jim Lux wrote: This makes a good case for the 30dB/decade very close in Somewhat had asked about how close in the 30 dB/decade is good for. There is a reference about this issue. The book Edson: Vacuum Tube Oscillators has what I believe is the first published

Re: [time-nuts] Close in phase noise of microwave VCOs

On 6/20/2015 1:16 PM, Alex Pummer wrote: Actually a YIG, even standalone has very good phase noise performance, as long as the tuning current is quite, once upon the time HP made some cheaper version of the 856x-es spectrum analyzers [ perhaps that was the 95xx ] they had the first LO just

Re: [time-nuts] Close in phase noise of microwave VCOs

On 6/17/2015 11:36 PM, Attila Kinali wrote: Do you have any recomendation, where an ordinary engineer could read up on this topic? Attila Kinali There is always Floyd Gardners, Phase Lock Techniques. However, a better tutorial would be the one written by HP's Dieter

Re: [time-nuts] Close in phase noise of microwave VCOs

On 6/18/2015 1:20 PM, Magnus Danielson wrote: The trick is to convert the 2nd degree loop to a 3rd degree loop, which then allows for a 12 dB/oct slope, to counteract the 9 dB/oct slope. No this is not correct. A very conventional Type 2 loop, where the loop filter consists of an integrator

Re: [time-nuts] Close in phase noise of microwave VCOs

On 6/17/2015 8:22 AM, Jim Lux wrote: I'm looking for some representative data for inexpensive microwave VCOs (in the 2.5-6 GHz range, in general). Not in a locked loop situation, If the phase noise data you have goes to a low enough frequency to get below the 1/f corner (which is the case

Re: [time-nuts] Close in phase noise of microwave VCOs

On 6/17/2015 8:22 AM, Jim Lux wrote: I'm looking for some representative data for inexpensive microwave VCOs (in the 2.5-6 GHz range, in general). Not in a locked loop situation, If you are working up to 2.5 GHz, you can get a low power chip for $2 from Analog Devices that has a VCO and

Re: [time-nuts] Modulation Domain Analysis

That's interesting. I worked for the HP Santa Clara Division from 1979 until just before it was closed in 1998. I forget who invented MDA at SCD, but it was hyped like it was some new concept and I never heard anything about the HP9540. Many times someone would come to me and ask me about some

Re: [time-nuts] Using CPLD/FPGA or similar for frequency divider

The counter only had to run at ~50 MHz, on account of our mode locked laser ran at that frequency. I don't remember what the CPLD was rated at. Rick On 6/5/2015 8:19 PM, Hal Murray wrote: rich...@karlquist.com said: I used a CPLD in a 900 GHz (that's right 900 GHz) optical sampling scope

Re: [time-nuts] Using CPLD/FPGA or similar for frequency divider

I used a CPLD in a 900 GHz (that's right 900 GHz) optical sampling scope timebase. It was great because you just write a 17 bit counter in VHDL and there it is. You don't have to know anything about building digital hardware any more (40 years of experience wasted). Nobody cares about look

Re: [time-nuts] Nature: Hyper-precise atomic clocks face off to redefine time

Can someone explain to me how this is going to work in light of the fact that each clock is in a different gravitational field? Or is accuracy not the measurement, but rather stability? No, that can't be because any lab that wants to measure stability merely needs to build two or three copies

Re: [time-nuts] Divider circuit for Rubidium Standard

The only gates that seem to do very well are high speed (as in 74AC or faster) silicon CMOS. You need to run them with a fairly clean supply and feed them with a p-p input that matches the supply voltage. Other than that, not a lot of magic. Are they ideal - surely not. Will they hit 2x10^-13

Re: [time-nuts] Divider circuit for Rubidium Standard

On 5/20/2015 11:22 AM, Magnus Danielson wrote: The older HP counter manuals explained it very nicely too, as they illustrated the slew-rate amplitude noise to time-noise conversion. What do amazes me is the fact that I've yet to see a counter input channel which takes care to square up the

Re: [time-nuts] Divider circuit for Rubidium Standard

On 5/8/2015 2:19 PM, Bob Camp wrote: On May 7, 2015, at 11:09 AM, Attila Kinali att...@kinali.ch wrote: On Wed, 06 May 2015 18:09:03 -0700 Richard (Rick) Karlquist rich...@karlquist.com wrote: A standard input on a frequency counter is not a very demanding thing in the hierarchy

Re: [time-nuts] Divider circuit for Rubidium Standard

On 5/6/2015 3:24 PM, Bob Camp wrote: Hi A standard input on a frequency counter is not a very demanding thing in the hierarchy of TimeNut signals. You can drive any of them with some pretty simple logic gate based circuits. No need to spend a lot of money. Bob Logic gate, yes.

Re: [time-nuts] Divider circuit for Rubidium Standard

On 4/26/2015 3:51 AM, Bryan _ wrote: All: P I was looking at the project from David partridges web site http://www.perdrix.co.uk/FrequencyDivider/index.html -=Bryan=- ___ This is a comparator based

[time-nuts] OT: PDF editing (was: Re: Ultra High Stability Time Base Options for 53132A)

On 5/4/2015 5:25 PM, J. L. Trantham wrote: Charles, Thanks for the help. I need to learn how to add text to .PDF documents. Go to: www.tracker-software.com and download (for free): PDF-Xchange viewer. Rick Karlquist N6RK ___ time-nuts

Re: [time-nuts] HP5328A HP5328B option 040

On 4/23/2015 12:20 AM, VK2DAP wrote: Dear time-nuts, I have a question about the HP5328A and HP5328B universal counters. 1) Generally speaking, would it be correct to say that when a product model number changes from A to B, that represents an improvement or major update to a product? 2) I

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