Design of Squaring Loop Based on Direct Carrier Extraction
Zou Tengjian · Modern Electronics Technique · 2010
Carrier recovery is a vital part for the phase modulation software defined radio receiver.A squaring loop added a multiplier is proposed for the carrier synchronization in communication based on the traditional squaring loop.When the Numerical Controlled Oscillator(NCO) is realized on FPGA,frequency of the squaring loop could be directly locked at the carrier frequency without two divided-frequency treatment by using the orthogonal property of sine wave.Then,the working principle and design idea are provided,the structure diagram and simulation waves in Simulink are given.Finally,the squaring loop carrier extraction has more extensive application value because it has more brief circuit and it can be used in a higher frequency than the tradition one.