What frequency is 0 Volts?

[Neil Johnson]

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Date: Tue, 25 Mar 1997 19:42:57 +0100
To: synth-diy at horus.sara.nl
From: Wim Verheyen <catwim at innet.be>
Subject: What frequency is 0 Volts?
Cc: Bob Zimmer <bzimmer at voicenet.com>
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     Another, perhaps wider, approach would be to define some standard 
     voltage/frequency point from which everything else would be defined.
     
     For example, the system I use when using/designing/building osc.s is 
     to define the control voltage 5.00 volts as being Middle C (frequency 
     of 261.6256 Hz).  Then any other frequency/voltage setting can be
     immediately determined; for example the control voltage for A above 
     middle C (tuning standard 440.0 Hz) requires a voltage of 5.750 volts. 
      So by providing a fixed, temp. stable voltage reference I can tune 
     all my oscs up relatively quickly, and know that they will be pretty 
     close to one another before final tuning to the chosen master osc.
     
     Applying this method to the problem of to what frequency zero volts 
     corresponds, using my system the answer is about 8.1758 Hz (i.e. C-2). 
      If it so happens that a particular osc. cannot reach that low, so be 
     it, but at least it will be compatible with all your other osc.s 
     higher up the scale.
     
     Hope this makes sense...
     
     Neil
     =====
     
+---------------------------+-----------------------------+
 Neil Johnson               * All thoughts and opinions
 Cambridge Consultants Ltd  * expressed here are my own.
 Cambridge, England         * Heck, even _I_ don't believe
 email: nj at camcon.co.uk     * what I say at times.....
+---------------------------+-----------------------------+ 

     
     


______________________________ Forward Header __________________________________
Subject: What frequency is 0 Volts?
Author:  Wim Verheyen <catwim at innet.be> at Internet-PO
Date:    25/03/97 19:42


>If one was to trim these out so that they proper frequency at 0 Volts, what 
>should that frequency be?
     
That's a bit difficult to say, it depends what your initial control settings 
are. Suppose they are at their lowest setting, then you should trim your
VCO so that it reaches its lowest (specified) frequency. That should be 
20 Hz max. preferably lower if possible, something like 5 Hz.
     
Hope this helps,
---------------------------------------------
 Wim Verheyen
 catwim at innet.be
 http://www.club.innet.be/~year0828/wim.html 
 belkurz or kurzbel on undernet irc
---------------------------------------------