An integrated solution for audio processing and signalling in mobile radio systems

An implementation of the circuitry for the audio signal and subaudio signalling processing on the Italian Mobile Radio System is described. The overall system was realized with two different CMOS custom circuits and a few other discrete components. The two chips were designed with the switched capacitor (SC) technique and integrated in a 3µ double poly CMOS technology. The system dissipates about 140 mW with a 5V single power supply.