[sdiy] Speaking of the Elektor Vocoder (and the Korg Vocoder)

[Neil Johnson]

Not quite (although kind of related)

- On a frequency counter it will count the number of pulses received  
in a given time window (ignoring HP's period measuring trick).  So to  
measure fractional Hertz you need a time window large enough to be  
able to measure less than 1Hz, i.e. >1sec.

- On a spectrum analyzer the issue is the settling time of the high-Q  
bandpass filter.  If you sweep it too fast you'll never let the  
filter settle and so be unable to make a sensible power measurement.

Neil



On 23 Feb 2008, at 20:55, anthony wrote:

> Is it sort of similar to the fact that I have to set the gate time  
> to 10 sec. on my frequency counter to get a fractional Hertz  
> resolution? It could be because my counter is like, "C'mon man! I  
> can do 1GHz! What's this 20,000.5 Hz crap?"
>
>> Hi,
>>
>>> The finer you require the frequency resolution to
>>> be, the more time needs to go by before you get a correct  
>>> result.   This
>>> is no different in the analog domain than in the digital domain.
>>
>> A nice example of this is the behavior of spectrum analyzers - the  
>> narrower the bandwidth the slower the maximum scan rate.  I was  
>> introduced to this phenomenon by the venerable old HP 141T.
>>
>> Neil
>> --
>> http://www.njohnson.co.uk
>>
>>
>>
>> _______________________________________________
>> Synth-diy mailing list
>> Synth-diy at dropmix.xs4all.nl
>> http://dropmix.xs4all.nl/mailman/listinfo/synth-diy
>>
>
>
> _______________________________________________
> Synth-diy mailing list
> Synth-diy at dropmix.xs4all.nl
> http://dropmix.xs4all.nl/mailman/listinfo/synth-diy

--
http://www.njohnson.co.uk