| 摘要 |
PURPOSE:To improve automatically the SSB sound quality by detecting the difference between a transmission frequency and a reception frequency from a short time frequency spectrum and a cepstrum of received sound so as to obtain the sound correcting the difference in transmitting the sound in an SSB. CONSTITUTION:A received sound waveform signal of a carrier suppression single side band communication system (SSB) is fed to a terminal 10. The waveform is segmented by a section length (window length) T, the result is subject to Fourier transformation and transformed into a short time frequency spectrum G(f). The cepstrum is calculated, a peak value M corresponding to the fundamental period of the cepstrum is obtained, then the (f) is shifted by (h) to form (f-h), and the cepstrum is calculated to obtain the M. The (h) is varied to repeat the calculation of the cepstrum to recognize an hP to the maximum M, and the frequency of G(f) is replaced into the (f-hP), then a processed waveform signal having a prescribed section length is obtained by the inverse Fourier transformation, the processing above is repeated, the obtained processing waveform signals are overlapped to form the resulting waveform signal. |
