Study on Notch Filter Technology of Time-Phase Modulation

Considering the power spectrum of time-phase modulation (TPM), this paper presents a notchfilter design technique which can extract the phase change characteristics of TPM. The notch filter is designed according to the parameters of TPM signals. The received TPM signals are filtered by the notch filter, which can weaken the amplitude of time-phase modulation signals at the carrier frequency point and highlight the amplitude at phase change period at the same time. So the phase change information is converted into the amplitude information that can be detected through some amplitude threshold. Finally, the detailed simulation and analysis on notch filter effect, BER performance and bandwidth efficiency are presented. The simulation results show that the TPM system adopting notch filter technology can effectively recover the input digital information and improve the bandwidth efficiency, while maintaining the system transmission performance.