Integration of a CMOS mixed-analog-digital eight channel speech transmission circuit

An eight channel speech transmission circuit with single sideband (SSB) modulation has been developed. The circuit includes signal amplifiers, various modulators and filters. Clocks for the switched capacitor filters, the modulators and the external controller are derived from the integrated oscillator. With a few additional components it is possible to build communication devices which can be combined to systems of more than 100 stations. The IC has been integrated in a 3 mu m double poly process.