A new CMOS differential input FM quadrature demodulator

This paper presents a new CMOS differential input FM quadrature demodulator for integrated circuits. The proposed circuit is based on Bilotti's quadrature demodulator that uses an external differential phase shift network and a differential phase detector with a single ended output. The phase detector is represented by an analog multiplier implemented with a Gilbert cell and the phase shift network is an external RLC resonator circuit. The current consumption of the FM detection stage is about 258μA from a 3.3V supply voltage. The simulations performed in 0.13μm CMOS technology confirm the theoretical result.