Re: [time-nuts] Frequency counter questions

Hi, Many modern counters use this trick too, but much more gift-wrapped, in that they themselves shift their oscillator to measure the shift and hence figure out which overtone is being used and hence derive the correct frequency. With HP5245 etc you had to do a little work on your own for

Re: [time-nuts] Frequency counter questions

And there was the HP 540 and the HP 2590B... I still use a HP 2590B for frequency measurement and in conjunction with a HP 851B display as a spectrum analyzer. John WA4WDL > > On June 8, 2017 at 8:35 AM Scott McGrath wrote: > > The heterodyne trick has been

Re: [time-nuts] Frequency counter questions

Hi The heterodyne approach dates back at least into the 1930’s in general lab use. I’m sure it dates well before that on an experimental basis. The LM and BC-221 frequency meters are good examples of it’s use. Adding an “error multiplier” to the setup could give you a very impressive

Re: [time-nuts] Frequency counter questions

The heterodyne trick has been done before the first 'Modern' frequency counter the HP 5245 used plug ins to extend its range to 18 Ghz by doing exactly that. The plug in contained a tunable LO mixer and indicator to show tuning lock These were a pain to use but they beat the 'frequency

Re: [time-nuts] Frequency counter questions

Hi Single mixer into a computing counter was the way this stuff was done for a *lot* of years. The sort of resolution you needed a fancy counter for back in 1969 is well within the F7 board’s capabilities. What you get for resolution is often less of an issue than the accuracy of the readings.

Re: [time-nuts] Frequency counter questions

We do it and get at 1 sec 1 E-13 resolution and 1 E-12 accuracy for the work we do. Bert Kehren In a message dated 4/26/2017 3:00:54 P.M. Eastern Daylight Time, alw.k...@gmail.com writes: I am surprised that no one has mentioned the idea of heterodyning a known frequency with the

Re: [time-nuts] Frequency counter questions

message From: Bruce Griffiths <bruce.griffi...@xtra.co.nz> Date: 4/26/2017 2:19 PM (GMT-08:00) To: Discussion of precise time and frequency measurement <time-nuts@febo.com>, al wolfe <alw.k...@gmail.com> Subject: Re: [time-nuts] Frequency counter questions Use

Re: [time-nuts] Frequency counter questions

Use a USB or LSB mixer, it only requires a few more parts and a little ingenuity. Bruce > > On 27 April 2017 at 06:52 al wolfe wrote: > > I am surprised that no one has mentioned the idea of heterodyning a > known frequency with the unknown to measure the

Re: [time-nuts] Frequency counter questions

I am surprised that no one has mentioned the idea of heterodyning a known frequency with the unknown to measure the unknown. I use a Minicircuits doubly balanced mixer fed on one port from a PTS160 synthesizer that is locked to 10 mhz. from a TrueTime xl-ak GPS locked receiver. The second port is

Re: [time-nuts] Frequency counter questions

High end frequency counters usually go to some effort to prevent synchronization between the input signal and the gate. Some DSOs do as well. Synchronization can exasperate certain errors and asynchronous operation provides better results when many measurements are averaged. On Tue, 25 Apr 2017

Re: [time-nuts] Frequency counter questions

I don’t know what I was thinking when I asked this question as we don’t control the gate timing in a referenced counter. > On Apr 26, 2017, at 3:59 AM, Bob kb8tq wrote: > > Hi > >> On Apr 26, 2017, at 12:29 AM, Jerry Hancock wrote: >> >> Do typical

Re: [time-nuts] Frequency counter questions

Hi > On Apr 26, 2017, at 2:31 AM, Mark Sims wrote: > > If your frequencies of interest can be divided down to to the 1PPS range, > the TAPR TICC makes for an excellent frequency counter. The TADD-2 Mini > divider handles 1/2.5/5/10 Mhz or with a PIC chip swap 1/5/10/15

Re: [time-nuts] Frequency counter questions

Hi > On Apr 26, 2017, at 12:29 AM, Jerry Hancock wrote: > > Do typical frequency counters start their gate in phase with the incoming > signal? I guess the > answer would be, "It depends." I was just thinking about how I would program > the STM32F7 > counter I am

Re: [time-nuts] Frequency counter questions

Hi, On 04/26/2017 06:29 AM, Jerry Hancock wrote: Do typical frequency counters start their gate in phase with the incoming signal? I guess the answer would be, "It depends." I was just thinking about how I would program the STM32F7 counter I am designing. No. The start of the gate arms

[time-nuts] Frequency counter questions

If your frequencies of interest can be divided down to to the 1PPS range, the TAPR TICC makes for an excellent frequency counter. The TADD-2 Mini divider handles 1/2.5/5/10 Mhz or with a PIC chip swap 1/5/10/15 MHz. The TICC has around 100 ps of jitter so you can get 1E-10 resolution at 1

Re: [time-nuts] Frequency counter questions

Do typical frequency counters start their gate in phase with the incoming signal? I guess the answer would be, "It depends." I was just thinking about how I would program the STM32F7 counter I am designing. btw, Gilbert, a local time-nut, sold me a 5335 today so I will be able to buiild

Re: [time-nuts] Frequency counter questions

Hi Keep in mind the previously stated limitation - Your GPSDO is only just so accurate. If you *could* read 0.001 Hz on a 100 MHz signal in a second, the GPSDO would not be anywhere near good enough as a reference. Keeping track of that sort of stuff is one reason a lot of companies train you

Re: [time-nuts] Frequency counter questions

So the STM App note An-4776 teaches how to use an external clock and it looks pretty accurate in implementation. I’ve read thru the code and it looks easy to implement. Now I just need to bring another signal in and count it. I’ll be working on some code this afternoon to implement the

Re: [time-nuts] Frequency counter questions

Hi > On Apr 25, 2017, at 8:53 AM, jimlux wrote: > > On 4/25/17 4:42 AM, Bob kb8tq wrote: >> Hi >> >>> On Apr 25, 2017, at 1:24 AM, Orin Eman wrote: >>> >>> On Mon, Apr 24, 2017 at 5:16 PM, Bob kb8tq wrote: >>> Hi

Re: [time-nuts] Frequency counter questions

On 4/25/17 4:42 AM, Bob kb8tq wrote: Hi On Apr 25, 2017, at 1:24 AM, Orin Eman wrote: On Mon, Apr 24, 2017 at 5:16 PM, Bob kb8tq wrote: Hi On Apr 24, 2017, at 6:54 PM, Hal Murray wrote: kb...@n1k.org said: You have a

Re: [time-nuts] Frequency counter questions

Hi > On Apr 25, 2017, at 1:24 AM, Orin Eman wrote: > > On Mon, Apr 24, 2017 at 5:16 PM, Bob kb8tq wrote: > >> Hi >> >> >>> On Apr 24, 2017, at 6:54 PM, Hal Murray wrote: >>> >>> >>> kb...@n1k.org said: You have a “gate”

Re: [time-nuts] Frequency counter questions

On Mon, Apr 24, 2017 at 5:16 PM, Bob kb8tq wrote: > Hi > > > > On Apr 24, 2017, at 6:54 PM, Hal Murray wrote: > > > > > > kb...@n1k.org said: > >> You have a “gate” from the GPSDO and a “signal” from somewhere else. If > you > >> want the STM to do the

Re: [time-nuts] Frequency counter questions

Hi > On Apr 24, 2017, at 6:54 PM, Hal Murray wrote: > > > kb...@n1k.org said: >> You have a “gate” from the GPSDO and a “signal” from somewhere else. If you >> want the STM to do the whole thing, the “gate” pin needs to get the job done >> in X +/- 1 cycles of the

Re: [time-nuts] Frequency counter questions

Hi I believe what you are going to find is that the 3586 has an IF strip in it. It does a heterodyne process to the IF center frequency and then indicates things from there. If the IF strip is out of alignment, you get a reading error. Probably worth digging into the service manual on the 3586.

Re: [time-nuts] Frequency counter questions

kb...@n1k.org said: > You have a “gate” from the GPSDO and a “signal” from somewhere else. > If you > want the STM to do the whole thing, the “gate” pin needs to get the job > done > in X +/- 1 cycles of the “signal” pin. Delay X (if it’s consistent) > isn’t > a problem.

Re: [time-nuts] Frequency counter questions

Bob, I have an STM32F769 disco as well as the Nucleo version. The big difference between the two is the LCD display on the Disco from what I remember. I’ll play around with the code this week and report back. ___ time-nuts mailing list --

Re: [time-nuts] Frequency counter questions

Hi > On Apr 24, 2017, at 3:49 PM, Chris Albertson > wrote: > > On Mon, Apr 24, 2017 at 10:13 AM, Bob kb8tq wrote: > >> Hi >> >> Some of the process below is “not trivial”. One example: >> >> You have a “gate” from the GPSDO and a “signal” from

Re: [time-nuts] Frequency counter questions

Orin, Thanks, this goes beyond interesting and I don’t know how you found it. I’ll be staring at this doc for the rest of the week. I have a dozen or so of the Nucleo boards around include the high end F7 types so I’ll see if I can duplicate their code on the System Workbench they reference

Re: [time-nuts] Frequency counter questions

Hi One advantage of keeping this on list — There are 3586B Guru’s running around here. I’m sure one of them will hop in to explain a bit more about what’s going on inside that beast. Since (as you point out) you can put the same signal in as the reference, it may be as simple as cranking pot

Re: [time-nuts] Frequency counter questions

Hi Jerry, See AN4776 on st.com. Section 2.6 looks particularly interesting. Orin. On Mon, Apr 24, 2017 at 12:06 PM, Jerry Hancock wrote: > This is an exercise more than anything. It started when I noticed the > counter in a 3586B I purchased was +1 count unless I dropped

Re: [time-nuts] Frequency counter questions

On Mon, Apr 24, 2017 at 10:13 AM, Bob kb8tq wrote: > Hi > > Some of the process below is “not trivial”. One example: > > You have a “gate” from the GPSDO and a “signal” from somewhere else. If you > want the STM to do the whole thing, the “gate” pin needs to get the job > done in

Re: [time-nuts] Frequency counter questions

This is an exercise more than anything. It started when I noticed the counter in a 3586B I purchased was +1 count unless I dropped the input frequency .25hz. I was using my GPSDO reference for it and the 3336 it was counting. I then took my GPSDO and tried reading that directly and I see the

Re: [time-nuts] Frequency counter questions

Hi Some of the process below is “not trivial”. One example: You have a “gate” from the GPSDO and a “signal” from somewhere else. If you want the STM to do the whole thing, the “gate” pin needs to get the job done in X +/- 1 cycles of the “signal” pin. Delay X (if it’s consistent) isn’t a

Re: [time-nuts] Frequency counter questions

On Sun, Apr 23, 2017 at 6:25 PM, Jerry Hancock wrote: > > > So to summarize, if I limit my high resolution to 99,999,999.999hz and use > a gate of 1000 seconds, would that get me to .01hz? If not, then what > would the possible resolution be? > It is best to keep this kind of

Re: [time-nuts] Frequency counter questions

Jerry, for a 100MHz PIC based counter a prescaler will be necessary. But it will not be necessary for a 30MHz counter. Prescalers do not have to be by divisors of 10. I recall the PIC counter input to be good to 50MHz so the prescaler could just be a divide by two if you need a 100MHz counter

Re: [time-nuts] Frequency counter questions

Hi Let’s back off a bit. To most of us, a 12 digit counter displays 12 digits regardless of the frequency you put into it. That’s been the way good bench counters have done it since the early 1970’s. Typically the number of digits is specified at a one second gate time. An HP 5335 is one

Re: [time-nuts] Frequency counter questions

Reciprocal counter where one measures the period of the output of a divide by N and then takes the reciprocal of this period multiplied by N as the frequency of the divider input. With a 100MHz clock one can achieve ~ 0.01ppm resolution for a 1 second averaging time. if one uses interpolators

Re: [time-nuts] Frequency counter questions

Confusion comes about because there is a ton of on-chip hardware an addition to the CPU. An edge detector, prescaller and a few hardware counters on the STM32. So I said he'd likely not be actually counting in software but just setting up the desired tiger condition, loading the prescaler then

[time-nuts] Frequency counter questions

For some reason I am not getting the individual emails so I apologize for not replying more promptly. I’ll have to check my profile. As far as I can tell from the notes, and by the way, the number of notes was why I was trying to move this off list, to get to .001hz I need to measure over

Re: [time-nuts] Frequency counter questions

Hi > On Apr 23, 2017, at 2:43 PM, Chris Albertson > wrote: > > On Sun, Apr 23, 2017 at 7:38 AM, Bob kb8tq wrote: > >> >> >> If you want to do something like the 53131 or even the 5335, you will need >> something a bit different >> than the F7 to

Re: [time-nuts] Frequency counter questions

m: time-nuts <time-nuts-boun...@febo.com> on behalf of Jerry Hancock > <je...@hanler.com> > Sent: Sunday, April 23, 2017 12:14:49 AM > To: Discussion of precise time and frequency measurement > Cc: met...@hanler.com > Subject: [time-nuts] Frequency counter question

Re: [time-nuts] Frequency counter questions

Hancock <je...@hanler.com> Sent: Sunday, April 23, 2017 12:14:49 AM To: Discussion of precise time and frequency measurement Cc: met...@hanler.com Subject: [time-nuts] Frequency counter questions Hello, I would like to find a person that would be able to answer some frequency counte

Re: [time-nuts] Frequency counter questions

On Sun, Apr 23, 2017 at 7:38 AM, Bob kb8tq wrote: > > > If you want to do something like the 53131 or even the 5335, you will need > something a bit different > than the F7 to do it. They are wonderful MCU’s but not really fast enough > to do the fancy stuff. > Yes, But I assume

Re: [time-nuts] Frequency counter questions

Assuming you are counting every cycle with no pre-scaler and can't measure the period, the answer is easy. If you want to measure Hz then the gate needs to be 1 second. If you want to measure too 0.1 Hz then you need a 10 second gate. In your case 0.001 Hz you need to count for 1,000 seconds.

Re: [time-nuts] Frequency counter questions

Hi Counting 12 digits is relatively easy, if that is the only constraint. Bring your “signal” into one of the timer clock inputs on the MCU. If your “signal” is 10 MHz that will be simple. If it’s 30 GHz it will be more difficult. 10 MHz gives you 7 digits a second. To get to 12 digits, you

Re: [time-nuts] Frequency counter questions

Up to the point that, to get 1milliHz resolution, you have to wait 1000 seconds (without the prescaler)? If you have a prescaler then it will be N*1000 seconds... On Sun, Apr 23, 2017 at 9:14 AM, Jerry Hancock wrote: > Hello, I would like to find a person that would be able to

Re: [time-nuts] Frequency counter questions

Hi Jerry, Consider building a fractional frequency counter. In it, you will measure both the time and number of input events. Consider building a time-stamping counter, in which post-processing can combine multiple timestamps (each holding time and event counters), as post-processing can

[time-nuts] Frequency counter questions

Hello, I would like to find a person that would be able to answer some frequency counter questions I have. Basically, I am thinking of building my own using one of the high end STM32F7 boards as the counter. I would like it to count reliably to 12 digits (e.g. 30,000,000.001x hz). I am