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# Reciprocal Counter Demo

• Posts: 14,289
Rayman wrote: »
I had no idea what "reciprocal counter" meant, but I got curious just now and googled this up:
https://community.keysight.com/community/keysight-blogs/general-electronics-measurement/blog/2018/02/26/how-does-a-frequency-counter-work

It's a simpler thing than I imagined...

Yes the block diagram and maths are simple.
Chip added support in the smart pins to make the hardware details simple too..
(it can get tricky to ensure the two captures of time and cycles are made on the same edge, and ideally, you want lossless/gapless capture too, so 10 or 100 captures of time and cycles can be summed to give higher precisions )
• Posts: 10,485
I think it should actually be called "period counter".
I guess they mean "reciprocal of frequency" counter.
But "reciprocal of frequency" == period.
I think that would make usage more clear.

But, when you google "period counter" you get other stuff, which is maybe why the chose this name...
• Posts: 575
@evanh

I used it to do the other waves that you helped me with in the past.
• Posts: 14,289
Rayman wrote: »
I think it should actually be called "period counter".
I guess they mean "reciprocal of frequency" counter.
But "reciprocal of frequency" == period.
I think that would make usage more clear.

But, when you google "period counter" you get other stuff, which is maybe why the chose this name...

I think it started as a simple one-word prefix so 'Frequency Counter' became 'Reciprocal Frequency Counter'.

If you wanted to create a new name, 'period counter' infers it measures a single periods, which is inaccurate.
'whole periods timer' is clearer, in that now includes key elements of measuring the time over N Whole Periods, and then calculates N/Time to give Cycles/Second units.
- however, because the final units are Hz, including Frequency in the name seems important. - Instrument users care less about the how, than what they ultimately measure.

On that note, the thread tile would be better as Reciprocal Frequency Counter Demo