| 摘要 |
PURPOSE:To prevent erroneous synchronization from being generated by comparing the output signal of an intermediate frequency filter of narrow band area to filter an inverse diffusion signal with that of a sideband filter having sensitivity on the sidebands on both sides of an intermediate frequency, and taking synchronization by their level difference. CONSTITUTION:A reception signal is a signal on which frequency diffusion is applied, and it is multiplied by a local reference signal 2 performing phase slippage by a correlator 3, then, is converted to the intermediate frequency. The output of the correlator 3, after being filtered by the intermediate frequency filter 4 and amplified by an intermediate amplifier 5, is detected by a detector 6. Also, the output of the correlator 3, after being filtered by an intermediate frequency blocking filter 10 and amplified by an intermediate frequency amplifier 11, is detected by a detector 12. When the fact that the DC level of the detector 6 exceeds that of the detector 12 remarkably is detected by a comparator 13, the clock phase shift of a clock generator 8 is fixed. Thus, the erroneous synchronization can be prevented from being generated. |
