An Efficient Demodulation Approach for Sidetone Distance Measurement

This paper presents an efficient demodulation method based on sidetone ranging. To measure the distance between two terminals precisely, the carrier and sidetone should be tracked and recovered efficiently. A multi-rate filter has been proposed, which completes the functions of data extraction and anti-aliasing. A phase-locked loop based on orthogonal two channel signals is proposed, which is more suitable for carrier tracking. A complex multiplier is applied in a phase-locked loop, achieving the purpose of structural simplification. Some of the structures are verified and the key parameters are obtained by MATLAB. Finally, the functions are realized in Vivado by using Verilog language and IP cores.