An Integrated CMOS DPQSK Demodulator for NICAM Data Recovery

A fully integrated DPQSK demodulator circuit is presented, intended for recovering NICAM audio data from TV baseband signals. The demodulator is based upon an analogue Costas loop embedded in a zero-IF receiver system. Both continuous-time and switched capacitor techniques are used to perform the selection of the data signal from the high level adjacent signal components. Response selection together with an AGC loop allow operation with differing TV transmission standards. The circuit is fabricated in 0.8¿m CMOS and operates from a 5V supply.