| 摘要 |
PURPOSE:To attain simple constitution without requiring a VCXO and a phase synchronizing circuit by allowing a slave station to extract a frequency synchronizing signal of an integer multiple of a prescribed frequency transmitted from a master station so as to generate a basic frequency for carrier with frequency division. CONSTITUTION:A basic frequency and a frequency synchronizing signal generator 21 generates basic frequencies 202-204 of carrier frequencies 4kHz, 12kHz and 124kHz and a frequency synchronizing signal 205 in 4,092kHz being an integer multiple from a frequency signal in 372kHz generated by a main oscillator 1 of a master station 300. They are applied respectively to a channel carrier 3, a group carrier 4 and a supergroup carrier 5 to generate a carrier required for a multiplex circuit 22. Then a signal transmitted to a slave station 301 via a transmission line 7 passes through a separation circuit 31 and a band pass filter 32, where a frequency synchronizing signal in 4,092kHz is extracted. Then the signal is frequency-divided by frequency dividers 35-37 and a basic frequency is formed. |
