[sdiy] frequency counter

[Ian Fritz]

At 12:40 PM 6/26/2004, WeAreAs1 at aol.com wrote:

>In a message dated 6/26/04 8:22:12 AM, ijfritz at earthlink.net writes:
>
><< I won't argue with you, but could you just say what is wrong with using a
>counter?  It's what I've always used, and it certainly *seems* to work.  In
>what sense doesn't it work? >>
>
>Your ears work better.  They have better pitch resolution than even the
>finest frequency counter (that we could afford, that is).  Lack of 
>resolution at
>the high end of the scale can be a real problem.  Also, counters don't 
>respond
>immediately to changes in pitch -- they take some time to settle (some of 
>them
>can REALLY take some time...)  Mind you, I'm not talking about finding a
>particular *note* -- I'm talking about fine-tuning VCO's until they 
>absolutely
>track each other over many octaves.  Go ahead, try it sometime.  That is, try
>tuning a pair of VCO's without using your ears.  No audio monitor, just your
>counter.  See how close you can get.  If you're satisfied with the result, 
>then I
>guess that's what matters.  It seems like an exercise in futility to me,
>especially when we all already have a pair of the best frequency counters 
>available,
>right on the sides of our heads.

Well, you're not telling me why a counter "won't work".   :-)

For what you seem to be doing, then I agree by ear is close enough.  But 
don't assume everyone is doing what you are doing.

For developing and testing new VCO designs it is crucial to have quantative 
data on tracking across the whole working range.  I don't see how you can 
get quantitative numbers for comparison of different designs by your 
method.  The idea that the ear is a more accurate frequency counter is 
preposterous.  Can anybody listen to a sound and tell me what its frequency 
is to .1%?  I've used two methods: (1) Measuring frequencies with a 1.000V 
CV difference and obtaining the tracking from the frequency ratios. (2) 
mixing a fixed xtal-controlled frequency with the VCO output, setting the 
frequencies by looking at the beat pattern, and measuring the CV 
differences.  Both seem to work OK.  I can't see any reason to spend $3k on 
a strobe meter.