An FM demodulator operating across 2–10GHz IF

An FM demodulator operating across 8GHz IF bandwidth for application in low-power, wideband heterodyne receivers is presented. A 4-stage ring oscillator is frequency modulated by a wideband input. Locking to 1/4th the input frequency, it divides the FM deviation by four, thereby reducing the energy required for wideband demodulation to 0.75nJ/bit. Autocorrelation of the quadrature-phased outputs using a new low-power folded CMOS mixer is capable of detecting FM up to 400Mb/s over 2-10GHz IF. The inductorless 65nm CMOS prototype circuit occupies 0.17mm² and dissipates 3mW from 1.2V.