A 65 nm CMOS Statistical Frequency Ratio Calculator for Frequency Measurement

The frequency ratio calculator (FRC) based on the statistical algorithm is proposed to obtain the integer and fractional frequency ratios of an input signal and a reference signal. The function of FRC can be used for fast frequency measurement of an unknown signal. Thanks to the proposed statistical algorithm, the circuit implementation of the FRC can be realized by synthesis of CMOS standard cell library and its performance is resistant to the variation of process, voltage, and temperature. The FRC is developed in a commercial 65 nm CMOS technology and its input signal frequency range is from 300 MHz to 1.5 GHz. The ratio calculation time takes only two reference cycles and the ratio accuracy is better than 0.003. The FRC consumes 12-42 mW of power from a 1.2 V supply voltage for different input frequency.