[sdiy] Frequency counter

[Roy J. Tellason]

On Saturday 29 January 2005 07:38 am, Mikael Mørup wrote:
> Hello group.
>
> After having spent a few days with my new (old) scope, i realize that i have 
> caught the gear plauge.

Heh.

> Now i need (well at least want) a frequency counter.

That's the "nifty!" factor at work there.

> What's the genereal concensus (asuming one exists) on frequency
> counters ?

For me,  I have interests that have ranged rather wider than synth DIY, and 
even still,  I don't think that one would be all that useful.  I do have some 
of that capability built into my Tek scope.  I've had some thoughts (years 
ago now) of building one,  but never followed through on that.  Got a hold of 
a homebrew one at one point,  never followed through on getting that working,  
either.  I still have it someplace,  dunno just where offhand.  And the 
prices of the original units are lower than they'd ever been,  though I 
haven't looked lately -- last one I remember hearing about was under $100 and 
was kind of limited in terms of its maximum frequency range.  Mostly 
optimized for some kinds of radio work,  I think,  and RF is probably where 
I'd see them getting the most use.

> Are the ones that are build into the better digital handheld Volt/Amp/Ohm
> meters good enough for synth DIY work ?

I haven't seen any of those myself.  My meters don't even have capacitor 
measurement built in.  I hear that some of them are getting quite capable 
these days.

> Do they have the required precision?

What _is_ the required precision?

> do they cover the low LFO range ?

You might run into a problem there -- accuracy is going to depend on how low 
the frequency of interest is compared to your sampling interval.  A one 
second interval seems to be pretty common,  and if your "low LFO range" is 
less than one occurrence per second,  it won't show up at all,  or will only 
show up as a bit of a bobble in the display's last digit.  For something like 
that what you probably want is an interval timer,  instead.

> Does anybody know of a (free / shareware / cheap) software
> frequency counter that would be adequate for SDIY work ?

Using what as hardware?

> Or are a dedicated counter the only way to go ?

Depends on what you want to do with it,  I guess.