[sdiy] VSM201 Vocorder Question

[rburnett at richieburnett.co.uk]

The narrow high-Q band-pass filters of the Vocoder channels do a good 
job of attenuating the "out of band" HF PWM carrier frequency. Roland's 
SVC-350 uses the same trick.  Control range of PWM'd CMOS switches 
acting as VCAs isn't that great though.

-Richie,


On 2016-01-02 19:23, Tim Ressel wrote:
> No kidding?  A nice, cheap, simple solution. I assume the PWM freq is
> above audio rates as there doesn't seem to be big low pass filtering
> going on. Interesting...
> 
> Thanks!
> 
> --TimR
> 
> On 1/2/2016 10:45 AM, Mattias Rickardsson wrote:
>> Indeed. PWMed analog switches. :-)
>> 
>> /mr
>> 
>> 
>> On 2 January 2016 at 19:29, Tim Ressel <timr at circuitabbey.com> wrote:
>>> Hi,
>>> 
>>> I've been looking at the VSM201 schematics and I can't find where the 
>>> VCAs
>>> are. Is there some cleverness I am missing?
>>> 
>>> --
>>> --Tim Ressel
>>> Circuit Abbey
>>> timr at circuitabbey.com
>>> 
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