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

Hi Rick, On Sat, 9 Jan 2016 14:45:43 -0800 "Richard (Rick) Karlquist" wrote: > This circuit is very similar to one that was championed by Tom > Faulker of HP/Agilent at the now closed Spokane site. Tom > measured the circuit at about -171 dBc/Hz. He was very

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

Moin Bruce, On Sat, 9 Jan 2016 21:36:35 + (UTC) Bruce Griffiths wrote: > Splitting the resistor in 2 and ac coupling the emitters together > reduces the effects of Vbe and/or base biasing mismatch allowing a more > symmetric output and/or operation at lower input

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

No, it was just word of mouth within the company. Somewhere I have a piece of notebook paper on which Tom drew the circuit. We did have internal forums where papers where presented, but this was never even published internally. As with all forums, a lot of stuff happens outside the official

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

Anything like the pnp + diode circuit shown in HP application note 301-1? Bruce On Monday, 11 January 2016 8:00 AM, Richard (Rick) Karlquist wrote: No, it was just word of mouth within the company. Somewhere I have a piece of notebook paper on which Tom drew the

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

Moin John, Yes, I know I am comming back to an "old" discussion, but I have questions that need to be answered! :-) On Wed, 06 May 2015 08:56:10 -0400 John Ackermann N8UR wrote: > Wenzel has published the schematic of an excellent squaring circuit. I > don't have the URL for

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

Splitting the resistor in 2 and ac coupling the emitters together reduces the effects of Vbe and/or base biasing mismatch allowing a more symmetric output and/or operation at lower input signal levels.The inductor reduces the high frequency variations in the total emitter current. It also

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] Divider circuit for Rubidium Standard

Bob wrote: The simple answer is that a biased fast CMOS gate will do a better job ADEV wise than your signal sources will. Maybe or maybe not, at tau ~1 second. Trouble is, as tau gets larger, the gate performs *worse*. The switching threshold of all MOSFET logic devices varies all over

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

Hi On May 23, 2015, at 12:37 AM, Charles Steinmetz csteinm...@yandex.com wrote: Bob wrote: The simple answer is that a biased fast CMOS gate will do a better job ADEV wise than your signal sources will. Maybe or maybe not, at tau ~1 second. Trouble is, as tau gets larger, the gate

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

...@n1k.org Date: Fri, 22 May 2015 17:31:47 -0400 To: time-nuts@febo.com Subject: Re: [time-nuts] Divider circuit for Rubidium Standard Hi What is your objective? Put another way: 1) How clean is your sine wave source? 2) What frequency (or range) are you trying to convert? 3) What level

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

After reading the posts on this subject I have a question. First, in my experience I used a rather simple circuit made from diodes used as limiters and a transistor feeding a logic inverter. No AGC. So here is my question. What is the proper circuit to use? I'd like to do a PSPICE and check

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

Hi What is your objective? Put another way: 1) How clean is your sine wave source? 2) What frequency (or range) are you trying to convert? 3) What level range are you trying to work with? 4) What is it going into (how clean is the next stage)? If you have an optical fountain that is good to

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

On Friday, May 22, 2015 10:48:16 AM Gerhard Hoffmann wrote: Am 21.05.2015 um 23:32 schrieb Magnus Danielson: On 05/21/2015 12:15 AM, Richard (Rick) Karlquist wrote: The counter front ends seem to be modeled after scope front ends and scope triggering circuits, where you can adjust the

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

Hi The simple answer is that a biased fast CMOS gate will do a better job ADEV wise than your signal sources will. If you want that to also hold for phase noise, run the gate on 5.5V and get the input signal as close to that (5.5V p-p) as you can. Bob On May 22, 2015, at 6:29 PM, xaos

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

Bob, This are all great questions. 1. Let's assume that it varies from a HP Signal generator to a home built device. However, If I was to build it I would expect to pay more and get better specs. I have a few HP 3325B's and a few 8660C. I would probably use those as inputs but not always. 2.

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

Hi To answer the next part of the question - simulation: Noise wise, Spice is fundamentally a linear analysis program. Logic gates mostly operate in a non-linear fashion (full on / full off). The noise models that are commonly used (when you can even find them) apply to fairly limited “active

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

Am 21.05.2015 um 23:32 schrieb Magnus Danielson: On 05/21/2015 12:15 AM, Richard (Rick) Karlquist wrote: The counter front ends seem to be modeled after scope front ends and scope triggering circuits, where you can adjust the triggering level. Any jitter in the triggering would normally

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

Hi On May 22, 2015, at 4:48 AM, Gerhard Hoffmann dk...@arcor.de wrote: Am 21.05.2015 um 23:32 schrieb Magnus Danielson: On 05/21/2015 12:15 AM, Richard (Rick) Karlquist wrote: The counter front ends seem to be modeled after scope front ends and scope triggering circuits, where you

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

Hi On May 20, 2015, at 11:27 PM, Alex Pummer a...@pcscons.com wrote: once upon the time at Gigatronics we compared logic devices noise and found that TTL were the quietest 73 KJ6UHN Alex Before the 74AC stuff came along, some flavor of TTL was the best bet. With TTL you needed to be a

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

On 05/21/2015 12:15 AM, Richard (Rick) Karlquist wrote: 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

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

Hi On May 19, 2015, at 7:10 PM, Richard (Rick) Karlquist rich...@karlquist.com wrote: 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:

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

Rick, On 05/20/2015 01:10 AM, Richard (Rick) Karlquist wrote: 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

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

HI On May 20, 2015, at 11:55 AM, Richard (Rick) Karlquist rich...@karlquist.com wrote: 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

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

once upon the time at Gigatronics we compared logic devices noise and found that TTL were the quietest 73 KJ6UHN Alex On 5/20/2015 3:15 PM, Richard (Rick) Karlquist wrote: On 5/20/2015 11:22 AM, Magnus Danielson wrote: The older HP counter manuals explained it very nicely too, as they

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 of

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

the existing circuitry. I would assume this would offer a greater improvement in phase noise? Cheers -=Bryan=- From: kb...@n1k.org Date: Fri, 8 May 2015 17:19:59 -0400 To: time-nuts@febo.com Subject: Re: [time-nuts] Divider circuit for Rubidium Standard Hi I guess the simple answer

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

would assume this would offer a greater improvement in phase noise? Cheers -=Bryan=- From: kb...@n1k.org Date: Fri, 8 May 2015 17:19:59 -0400 To: time-nuts@febo.com Subject: Re: [time-nuts] Divider circuit for Rubidium Standard Hi I guess the simple answer is “when you measure

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

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 of TimeNut signals. You can drive any of them with some pretty simple logic gate based circuits. No need to

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

Hi I guess the simple answer is “when you measure them that’s the result”. The slightly more complex answer is “fast silicon CMOS is indeed good, other types may require further analysis”. In general the faster stuff is better than the slower CMOS. Deeper into it you get to the fact that

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

Hi Rick: Any suggestions for a circuit with better performance. Purpose will be a external standard for a frequency counter. -=Bryan=- Date: Mon, 4 May 2015 21:09:51 -0700 From: rich...@karlquist.com To: time-nuts@febo.com Subject: Re: [time-nuts] Divider circuit for Rubidium Standard

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

measurement Subject: Re: [time-nuts] Divider circuit for Rubidium Standard This is a comparator based circuit. This will give you worse performance than just about anything else, but it may be good enough anyway. Rick Karlquist N6RK ___ time-nuts mailing list

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

The Phase noise floor (~-143dBc/Hz @ 1kHz) of the 10MHz output of that divider is about 17dBc/Hz higher than either the LTC6957-4 (demo board) or the Holzworth HX2410 (both ~ -160dBc/Hz @ 1kHz).All measured with a 10MHz +14dBm input signal.For offsets below a few Hz shielding of the circuitry

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

: Mon, 4 May 2015 21:09:51 -0700 From: rich...@karlquist.com To: time-nuts@febo.com Subject: 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

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

Rick: Any suggestions for a circuit with better performance. Purpose will be a external standard for a frequency counter. -=Bryan=- Date: Mon, 4 May 2015 21:09:51 -0700 From: rich...@karlquist.com To: time-nuts@febo.com Subject: Re: [time-nuts] Divider circuit for Rubidium Standard

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

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

as I don't need all the dividers, but it has the circuitry for the amplifiers and buffers as well wave shaping the input. Cheers -=Bryan=- From: kb...@n1k.org Date: Sun, 26 Apr 2015 09:56:17 -0400 To: time-nuts@febo.com Subject: Re: [time-nuts] Divider circuit for Rubidium Standard Hi

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

=- From: kb...@n1k.org Date: Sun, 26 Apr 2015 09:56:17 -0400 To: time-nuts@febo.com Subject: Re: [time-nuts] Divider circuit for Rubidium Standard Hi I would *assume* that either the 20 or 60 MHz is already a square wave. If they both are, use the 20, if not use which ever one

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

Hi I would *assume* that either the 20 or 60 MHz is already a square wave. If they both are, use the 20, if not use which ever one is a square wave already. Past that it is just a divide by 2 or a divide by 3 followed by a divide by 2. You want the last stage to be divide by 2 so the output

[time-nuts] Divider circuit for Rubidium Standard

All: Picked up a FE 5680B from Ebay awhile back. Appears to work fine, but is limited to a 1pps output. However there is a point on the PCB that's documented that has a 20Mhz output. There is actually a clean 60Mhz output as well.