[time-nuts] Question about frequency counter testing

Hal Murray hmurray at megapathdsl.net
Fri Apr 27 09:30:01 UTC 2018


olegskydan at gmail.com said:
> No, it is much simpler. The hardware saves time-stamps to the memory at each
> (event) rise of the input signal (let's consider we have digital logic input
> signal for simplicity). So after some time we have many pairs of {event
> number, time-stamp}. We can plot those pairs with event number on X-axis and
> time on Y-axis, now if we fit the line on that dataset the inverse slope of
> the line will correspond to the estimated frequency. 

I like it.  Thanks.

If you flip the X-Y axis, then you don't have to invert the slope.

That might be an interesting way to analyze TICC data.  It would work 
better/faster if you used a custom divider to trigger the TICC as fast as it 
can print rather than using the typical PPS.

------

Another way to look at things is that you have a fast 1 bit A/D.

If you need results in a second, FFTing that might fit into memory.  (Or you 
could rent a big-memory cloud server.  A quick sample found 128GB for 
$1/hour.)  That's with 1 second of data.  I don't know how long it would take 
to process.

What's the clock frequency?  Handwave.  At 1 GHz, 1 second of samples fits 
into a 4 byte integer even if all the energy ends up in one bin.  4 bytes, *2 
for complex, *2 for input and output is 16 GB.


-- 
These are my opinions.  I hate spam.






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