2 modules ideas

[jbv]

Looks like summer is the perfect time to come up
with new modules ideas... So here we go :

Below are short descriptions of 2 modules I've
been thinking of for a while :

1) "additive" synthesis

the square output of a VCO is fed into a logic divider
(CMOS or TTL) with at least the following outputs :
F/2, F/4, F/8, F/16, all squares and in sync.
Each of these SQ outputs is sent to a Square-to-sine
converter, which should give synched and octave
tuned sines.
Then, each sine is followed by a VCA (the hex-VCA
recently discussed here could be a cheap solution).

The idea is to use various CVs to drive the VCAs
and perform some sort of additive synthesis (or
at least play with harmonics)...

As for the input signal, one could use the SQ
of a VCO or any signal through a comparator
to get a SQ...


2) formant synthesis

the CEM3350 is a double VC BP filter with
VC bandwidth and VC resonnance...

The idea is to put several of those in parallel
and perform some formant synthesis by
controlling all CVs from a uC.

AFAIK, 7 to 8 formants are sufficiant for
acceptable speech synthesis. Therefore, putting
4 CEM3350 in parallel could allow some
speech / singing synthesis with white noise
or any VCO output...


If anyone has already worked on the above,
please direct me to the relevant URLs...

Thanx.

jbv