| 摘要 |
A multi-rate clock signal extracting device includes a light modulator, a photoelectric converter, a band-pass filter unit, a phase comparison unit, a bit rate changeover switch and a modulating electric signal generating unit. The light modulator modulates a light signal according to a modulating electric signal as a mixing signal obtained by mixing an electric signal with frequency f/(2j−1) and an electric signal with frequency &Dgr;f so as to output it as a modulated light signal. The modulated light signal is converted into a first electric signal by the photoelectric converter. A second electric signal group with frequency (2n−1)×&Dgr;f is generated from signal components with frequencies (2n−1)×&Dgr;f included in the modulated light signal by the photoelectric converter and the band-pass filter unit so as to be input into the phase comparison unit. The bit rate changeover switch selects an electric signal corresponding to the bit rate of the light signal so as to input it into a modulating electric signal generating unit. The modulating electric signal generating unit outputs the modulating electric signal.
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