| 摘要 |
PURPOSE:To make complete synchronous detection possible, by a constitution where the phase is not changed even if the input signal to the delay circuit of the PLL circuit which generates the carrier wave used for synchronous detection is changed from the center frequency slightly. CONSTITUTION:The AM signal received by antenna 1 is converted to an IF signal by mixer 2 and is applied to synchronous detector 6 through filter 4 and IF AMP5. The output of filter 4 is applied to PLL circuit 8 through delay circuit 7 to form a carrier wave for synchronous detection. At this time, if phase characteristic K2 of delay circuit 7 is set to satisfy K2=-1/K1[rad/Hz] when the phase characteristic of PLL circuit 8 is denoted as K1[Hz/rad], complete synchronous detection is possible even for incomplete tuning. |
