Abstract: Based on the theoretical expression of the highefficiency modulation extended binary phase shift keying(EBPSK) signal, the noncarrier frequency power spectrum component is analyzed, and the max power location was offset the carrier frequency is found. The transmitted power ratio of the modulated EBPSK signal under different band width is , simulated. The offset frequency is ser as the central frequency of the transmit forming filter and the system demodulation performance is simulated to reach a conclusion that the frequency departure could bring system performance gain. The theoretical derivation and simulation results show that the power of the EBPSK signal is not carriercentered distribution, and the lower frequency offset as the centre frequency forming filter could perform better.