| 摘要 |
PURPOSE:To satisfactorily recover a multiplex signal in spite of the adverse S/N of a reception signal by employing a pilot signal multiplexed with a broadcasting wave at the time of stereo broadcasting and reproducing a subcarrier. CONSTITUTION:If the reception signal 101 is stereo, a pilot signal reproduction circuit 102 can take out the pilot signal from the reception signal 101. The circuit 102 can provide a control signal 106 that discriminates whether the pilot signal is present or not. A multiplier circuit 104 multiplies a signal 103 to obtain a recovered subcarrier 105. When the signal 106 switches a changeover switch 107, the signal 105 is led to a multiplier circuit 111 and a pi/2 phase shifter 113. An axis I detection output from the circuit 111 and an axis Q detection output 116 from a multiplier circuit 112 are led to an axis I detection part and an axis Q detection part, respectively, and a multiplex signal is decoded. If the reception signal is not stereo, the signal 106 changes over the switch 107 to the side of a subcarrier recovering circuit 110, and the signal is used for detecting the multiplex signal 109.
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