Design of RC constant auto-calibration circuit for GSM handset

For the device error caused by the IC process, this paper designed a RC constant auto-calibration circuit for polyphase filter module in GSM system. The circuit used programmable capacitor arrays and search algorithm to rapidly tune the parameters to ensure the stability of the module. Simulation results show that: with 5 CNC mode tuning capacitor array, the tuning time error is not more than three clock cycles to meet the system requirements.