SSM2164 VCO

[Roman Sowa]

thank you all for the replies!

someone asked how to make triangle vco with vca:
ssm has current output so...
feed integrator's input (i used TL081and 470p styro-cap) with ssm
output.
TL's output goes to hysteresis-comparator, or Shmit-trigger if you like.
drive ssm signal input by 30k res from that comparator - done!
ssm control input with proper circuitry is VC directly - ssm sensitivity
is 185mV/oct (attenuator needed) and is phase-reversed - frequency
drops as VC rises (inverter needed)
as you see it's nothing more than you all probably seen or used.

>I am also interested on using SSM2164 as VCO chips,
> so more info would be appreciated (stability, tempco). 

> What's the difference in terms of stability, tracking and overall
quality?

i'm playing with it for only 2 days, so when i decide how my vco
will look like, i'll make some tests.

> Since I have some problems with quality saw->tri conversion,
> maybe it would be worth trying tri/square version.

it is worth it. the triangle looks (and sounds) perfect
but in sub-hertz region the slopes are not equal due to opamp bias
current
BTW have you tried saw2tri converter made with one transistor and 2
resisors?
i saw it on some of korg or roland schems. R are equal - the circuit
works like
inverter at low input voltages, and emmiter-follower at higher voltages
(although
output v is taken from collector)

> I suppose if I use SSM2164, there would be no need for
> exponential converter, since SSM2164 already has exponential control.
> How is with the tri->saw conversion?

true, no need for that...
tri->saw? i'd say there's no way to make it clean

> And a small note: using SSM2164 for a tri/square VCO,
> there is somehow difficult to implement linear FM.

no it's nooot...
but it involves next ssm, or using VC clamps following comparator
output.
after all, ssm's signal input is linear...

that's it for now. my vco has more to show...

Roman