[sdiy] SSM2164 Questions

[blacet at blacet.com]

--That is basically it.


> I don't have any 2164 chips here yet so I haven't had a chance to
> experiment. Looking at the datasheet I'm having a hard time figuring out
> the control port range/polarity.
>
> The Electrical Characteristics don't tell any more than this:
> ground referenced –33 mV/dB control port
>
> and the single supply example states: 0dB gain at Vc = V+/2.
>
> This leads me to believe the following when using a +/-15V supply...
> 1. There is 0dB of gain when the control port is at 0V.
> 2. Gain increases 1dB for every 33mV more negative the control voltage
> is (eg -99mV would be +3dB gain)
> 3. Gain decreases 1dB for every 33mV more positive the control voltage is.
> 4. The maximum attenuation is quoted as -100dB, so to get this you'd
> need 100 * 33mV = +3.3V
> 5. The maximum gain is quoted as +20db, so to get this you'd need 20 *
> 33mV = -0.66V
> 6. In normal synthesizer use such as a VCF you'd use an inverting
> summing stage for your CV inputs and add an offset so that with a 0V CV
> input you'd get maximum attenuation (somewhere around +3.3V), and gain
> would increase with increasing CV input voltage.
>
> For those that have played with these chips do these seem like
> reasonable conclusions?
>
>
> Regards,
> Stewart.
>
>
>
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