Thomas Henry Tunable Noise Source Question

[René Schmitz]

The idea was first take the log, then add your noise, then take the exp of
that feed it into the VCO. Then the noise modulation is constant with pitch. 

Bye,
 René

At 21:00 21.11.00 -0000, Hairy Harry wrote:
>The tempcos only cancel if you have a log/antilog function...
>so that is the equivalent of having the same input and output...
>
>if it was linear in... its linear out.
>
>The advantage is that if you are trying to do a multiply
>of two signals, you can log them, add them together, and anitlog...
>
>but each signal has to go through both stages...
>
>Am I correct here ???
>
>H^) harry
>
>
>>From: René Schmitz <uzs159 at uni-bonn.de>
>>To: music.maker at gte.net, synth-diy at node12b53.a2000.nl
>>Subject: Re: Thomas Henry Tunable Noise Source Question
>>Date: Tue, 21 Nov 2000 20:47:52 +0100
>>
>>At 04:48 21.11.00, Scott Gravenhorst wrote:
>> >Thanks René,
>> >
>> >This did cross my mind, but I keep thinking about all
>> >that messy tempco stuff.  I even looked up a schemo for
>> >a precision log converter... 3 op amps and some matched
>> >trannies.  It's looking like the simplest way so far
>> >is still the OTA, since it allows me to completely
>> >remove all of the expo stuff.
>>
>>But keep in mind that in this case the expos tempco would be cancelled by
>>the logs tempco, hence when you'd use the same transistor array for both
>>functions, you wouldn't have to worry about tempco compensation.
>>
>>Bye,
>>  René
>>--
>>uzs159 at uni-bonn.de
>>http://www.uni-bonn.de/~uzs159
>>
>>
>>
>
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http://www.uni-bonn.de/~uzs159