Alan built a reciprocal frequency counter. What sets reciprocal counters apart is that they adjust to the signal measured, sort of an auto-ranging feature.
It is AVR based and automatically enables or disables a prescaler to handle frequencies from 0.5 Hz to 100 MHz. It can give the same precision whether the signal is fast or slow…
[I have a] question about the front end. I’ve tried various input circuits, I’ve tried biasing inverters, schottky inverters, etc. I want the input to support even measuring mains voltages if possible.
Any suggestions for Alan?
What is your range of desired input ? as low as .1V peak to peak ???? up to 680V peak to peak ? ( which is 240VAC ) Once we know that we can design a front end.
The low end is the tricky part since the circuit must be sensitive enough to detect the low voltage.
I presume you want auto-ranging….. I presume you want an isolated ( ~1KV ) differential input that is good from .5Hz to 100MHz. Once we specify the functional requirements we can design the front end.
My email is yes atttt n o p e 9 dot c o m
Hello Gus,
I don’t recall if he specified what main line voltage he has. He gives more details in the forum post. First link in the paragraph, and if you have issues with the color scheme its the first sentence.
Is it any updates of project?
Anyone know of a chip [or circuit] for an *Integrating* Reciprocal Frequency Counter?
How does an integrating reciprocal frequency counter anyway? I’m flummoxed…
[Ouch] How does an integrating reciprocal frequency counter WORK anyway?
From what I understand, it adds phase detection to the start and end of the sample interval, to increase the resolution of the sample. Just the thing to add to a frequuency counter chip.
I found the FC-501 on Github, but the docs are in Russian and seem to lack detail.
Thanks, I couldn’t find anything on the intertubes on that…
@Alan: Assuming that by ‘integrating’ you meant ‘interpolating’ and by ‘FC-501’ you meant ‘FC-510’ then maybe you should ask the designer in the forum topic of his project…
http://www.eevblog.com/forum/projects/diy-interpolating-frequency-counter-fc-510/
Yep, that’s the one. Github version of files is at: https://github.com/ew1abz/fc-510
Go to the doc subdirectory, find instructions – in Russian.
There are Altera and AutoCad directories, and lots of photos of the front panels – but no actual schematics. Your link is much better, thank you.
The 501 / 510 was just a typo. However, since a sawtooth is the integral of the area of a pulse, I really thought it was “integrating”. rather than “interpolating”.