This module is designed to produce a variety of voice sounds.
It is based on Ai Cybernetic Systems model 1000 Speech Synthesizer.
It uses an XR2206 IC and a transistor based noise circuit for the sound sources. These and a pitch period control are switched on and off by a DG409 multiplexor.

The circuit requires three gate signals to operate, perfect for using with various CGS modules like the Master Divider or other cmos based sequencing circuits.
The output of this section is mixed and fed into 7 parallel bandpass filters. The filters have Q=10 and centre frequencies of 55, 110, 220, 440, 880, 1760, 3250 Hz.
Each filter has a pot to control the incoming signal and a switch to select whether the pots attenuate the signal or are mixed with a feedback signal from the output.
There is also an external input if just the filter section is to be used.

2/7/2010 built two versions of this on veroboard. One used an exponential input cct to control the 2206 , the circuit is a hybrid of one given in Electronotes and the typical one seen on just about every VCO these days. The other is similar to the 2206 control cct on Thomas Henry's XR2206 VCO, it is the better choice if you want to build this module. The schematic below is the circuit as it stands, works, doesn't sound anything like someone speaking but sounds pretty good anyway. The 880 and 3250 Hz filters oscillate at certain settings in resonant mode. TI filter design software was used to design the filters, if I were to build another I would use higher Q setting and try to get rid of the oscillations.

bindubba4 schematic jpeg [tested](234kB)