Re: [time-nuts] Performance verification for time counters

2017-11-29 Thread Hal Murray
kb...@n1k.org said: > The gotcha with a DDS in this case are the sawtooth spurs. To get them down > to the 5 ps level, you would need a DDS with a clock that is well into the > 100’s of GHz. I think that assumes you want to be able to generate an arbitrary frequency. Suppose I start with 10

Re: [time-nuts] Performance verification for time counters

2017-11-29 Thread Bob kb8tq
Hi That’s certainly part of the issue. The fact that you are measuring a transfer function in the phase domain is another issue. Before this gets to nutty, there is indeed a “peaking” spec on things like a stratum 1 through 4 device. That also gets carried into the OCx domains as well.

Re: [time-nuts] Performance verification for time counters

2017-11-29 Thread Tim Shoppa
At that low a frequency aren’t you actually testing the temperature and time stability of the gain controlling components? Tim N3QE > On Nov 29, 2017, at 9:04 PM, jimlux wrote: > >> On 11/29/17 5:53 PM, Bob kb8tq wrote: >> HI >>> On Nov 29, 2017, at 8:41 PM, jimlux

Re: [time-nuts] Performance verification for time counters

2017-11-29 Thread jimlux
On 11/29/17 5:53 PM, Bob kb8tq wrote: HI On Nov 29, 2017, at 8:41 PM, jimlux wrote: On 11/29/17 3:41 PM, Bob kb8tq wrote: Hi Needless to say *demonstrating* this 0.001 db sort of gain flatness on a repeater out to crazy low frequencies is a bit involved. It *is* a

Re: [time-nuts] Performance verification for time counters

2017-11-29 Thread Bob kb8tq
HI > On Nov 29, 2017, at 8:41 PM, jimlux wrote: > > On 11/29/17 3:41 PM, Bob kb8tq wrote: >> Hi >> Needless to say *demonstrating* this 0.001 db sort of gain flatness on a >> repeater >> out to crazy low frequencies is a bit involved. It *is* a great gig if you >>

Re: [time-nuts] Performance verification for time counters

2017-11-29 Thread jimlux
On 11/29/17 3:41 PM, Bob kb8tq wrote: Hi Needless to say *demonstrating* this 0.001 db sort of gain flatness on a repeater out to crazy low frequencies is a bit involved. It *is* a great gig if you happen to be a consultant … Bob demonstrating 0.001 dB (or would that really be 0.1 mB or

Re: [time-nuts] Wenzel VHF PLO Oscillators Off Frequency

2017-11-29 Thread Mark Goldberg
With help from an number of people who responded, I have gotten the Wenzel oscillators to work and provide a frequency locked external clock to a Perseus SDR radio. I had to add an external clock input to the Perseus and describe it at: https://sites.google.com/site/perseusmods/ Mark W7MLG

Re: [time-nuts] Performance verification for time counters

2017-11-29 Thread Bob kb8tq
Hi The key point here is the term “demonstrating”. When you get to 0.001 Hz it takes more than just a little time. Not very compatible with a production line. Yes you *might* ask “would anybody ever want that demonstrated ? “. The answer is yes, there are people out the that need it

Re: [time-nuts] Performance verification for time counters

2017-11-29 Thread Poul-Henning Kamp
In message <9793f6fa-cb78-4bf1-bc80-6b1a593fc...@n1k.org>, Bob kb8tq writes: >Needless to say *demonstrating* this 0.001 db sort of gain flatness on a >repeater >out to crazy low frequencies is a bit involved. It *is* a great gig if you >happen to be >a consultant ... No consultants

Re: [time-nuts] Performance verification for time counters

2017-11-29 Thread Bob kb8tq
Hi Needless to say *demonstrating* this 0.001 db sort of gain flatness on a repeater out to crazy low frequencies is a bit involved. It *is* a great gig if you happen to be a consultant … Bob > On Nov 29, 2017, at 6:36 PM, Poul-Henning Kamp wrote: > > > In

Re: [time-nuts] Performance verification for time counters

2017-11-29 Thread Poul-Henning Kamp
In message <409346f4-60e1-4cae-8602-84fb1c061...@n1k.org>, Bob kb8tq writes: >>> The HP3336 with its outstanding level-control is a much >>> overlooked bargain for this kind of stuff. >> >> I looked for the manual, and it seems to have ROM feeding values to a DAC. >> Is that not DDS?

Re: [time-nuts] Performance verification for time counters

2017-11-29 Thread Poul-Henning Kamp
In message <5e3f68620fdb8f2e5d62e9907a44c6eb.squir...@email.powweb.com>, "Chris Caudle" writes: >On Wed, November 29, 2017 3:51 pm, Poul-Henning Kamp wrote: >> While it is tempting and probably easiest to use a DDS style >> generator, I recommend a synthesized one instead, to avoid >>

Re: [time-nuts] Performance verification for time counters

2017-11-29 Thread Bob kb8tq
Hi There are a number of ways to build a synthesizer that do not involve a modern DDS architecture. The gotcha with a DDS in this case are the sawtooth spurs. To get them down to the 5 ps level, you would need a DDS with a clock that is well into the 100’s of GHz. Bob > On Nov 29, 2017, at

Re: [time-nuts] Performance verification for time counters

2017-11-29 Thread Chris Caudle
On Wed, November 29, 2017 3:51 pm, Poul-Henning Kamp wrote: > While it is tempting and probably easiest to use a DDS style > generator, I recommend a synthesized one instead, to avoid > trouble with numeric spurs. Can you describe the distinction you are making between a synthesized generator,

Re: [time-nuts] Performance verification for time counters

2017-11-29 Thread Poul-Henning Kamp
In message , Andy ZL3AG via time-nuts writes: >HP 5359A Time Synthesiser? If we're only talking 1PPS timestamping and nothing better and more flexible is available, then yes. -- Poul-Henning Kamp | UNIX since Zilog Zeus

Re: [time-nuts] Performance verification for time counters

2017-11-29 Thread Bob kb8tq
Hi > On Nov 29, 2017, at 5:16 PM, Andy ZL3AG via time-nuts > wrote: > > > HP 5359A Time Synthesiser? 100 to 200 ps jitter …. he’s after <5 ps Bob > > > On 30/11/2017, at 10:24 AM, Leo Bodnar wrote: > >> I am looking for an established and widely accepted procedure

Re: [time-nuts] Performance verification for time counters

2017-11-29 Thread Andy ZL3AG via time-nuts
HP 5359A Time Synthesiser? On 30/11/2017, at 10:24 AM, Leo Bodnar wrote: > I am looking for an established and widely accepted procedure for verifying > performance of high resolution time counters. > > I have designed a time stamping counter for qualifying 1PPS signal > performance against

Re: [time-nuts] Performance verification for time counters

2017-11-29 Thread Hal Murray
l...@leobodnar.com said: > Now, what would be recognised procedure for sweeping external input pulse > delay over few hundred ns in a controlled, measurable and repeatable way? How about using another crystal at a slightly different frequency? Suppose you start with 10.01 MHz and divide

Re: [time-nuts] Performance verification for time counters

2017-11-29 Thread Bob kb8tq
Hi The “simple / easy / quick” approach is a pps generated by source with a small frequency offset. If your objective is 5 ps, both your reference and your offset source will need to do better than that. While that sounds like it’s specific to this technique, it’s actually a more general

Re: [time-nuts] Performance verification for time counters

2017-11-29 Thread Poul-Henning Kamp
In message <5602c647-1251-4d78-b82e-798bfcd8b...@leobodnar.com>, Leo Bodnar writes: >Now, what would be recognised procedure for sweeping external input pulse >delay over few hundred ns in a controlled, measurable and repeatable way? When I did this (20 years ago :-), I used a signal

Re: [time-nuts] Performance verification for time counters

2017-11-29 Thread Magnus Danielson
Hi Leo, On 11/29/2017 10:24 PM, Leo Bodnar wrote: I am looking for an established and widely accepted procedure for verifying performance of high resolution time counters. Now, what would be recognised procedure for sweeping external input pulse delay over few hundred ns in a controlled,

[time-nuts] Performance verification for time counters

2017-11-29 Thread Leo Bodnar
I am looking for an established and widely accepted procedure for verifying performance of high resolution time counters. I have designed a time stamping counter for qualifying 1PPS signal performance against external reference (e.g. 10MHz master clock.) Simple design verification check I am

Re: [time-nuts] Designing an embedded precision GPS time server

2017-11-29 Thread Andrew Rodland
Hi Nick, I've got a project along those lines that I've been hacking on for the past three years or so, and always meaning to do a thorough writeup on. I'm more of a software than hardware guy, so the heart of it is a Taijiuino Due (a weird Chinese clone of the Arduino Due, so an 84MHz ATSAM3X8E,