[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

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

Hi > On Apr 23, 2017, at 12:43 PM, Richard Solomon wrote: > > At that resolution, you need a very accurate and stable Time Base. > > A GPSDO may not be good enough for 10 e12 measurements. > If buy some truly strange chance, this *is* a 100,000 second gate time exercise

Re: [time-nuts] Austron/ Systrom Donner 8181 Time Code Reader

Bill, actually what happened is the zener diode that the resistor fed shorted and that's the reason it burned up. I have two units with this issue and I cannot read the resistor value since it burned up. What I would love to know is what the original value of the dropping resistor was? 73 Dave

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

Re: [time-nuts] Frequency counter questions

At that resolution, you need a very accurate and stable Time Base. A GPSDO may not be good enough for 10 e12 measurements. 73, Dick, W1KSZ Sent from Outlook From: time-nuts on behalf of Jerry Hancock

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

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] Austron/ Systrom Donner 8181 Time Code Reader

Dave If you know the Zener voltage and the supply voltage then calculating a reasonable value for the series resistor is pretty straight forward Dave On 4/23/2017 2:31 PM, Dave Wood wrote: Bill, actually what happened is the zener diode that the resistor fed shorted and that's the reason

Re: [time-nuts] Austron/ Systrom Donner 8181 Time Code Reader

Here is a calculator to determine the resistor value. You will probably have to provide an external supply, at the zener voltage, to know what the current draw is for the calculator. You might find that the original resistor value was too

Re: [time-nuts] Austron/ Systrom Donner 8181 Time Code Reader

If you know what the zener is and what the unregulated supply voltage is, you should be able to calculate the resistance and power. Regards - Original Message - From: "Dave Wood" To: "Discussion of precise time and frequency measurement" Sent:

[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

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

Re: [time-nuts] Austron/ Systrom Donner 8181 Time Code Reader

Glenn, your calculator comes up with the value I first calculated, around 13k. However, I'm pretty sure the original value may have been 4 times higher based on the partially visible bands on one of the resistors that indicates it might have been a 56k. If I use the zener test current in the

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