| 摘要 |
PURPOSE:To perform accurate display which shows that a stereophonic broadcast is being received, by using an LPF, a limiter and detecting circuit to detect a stereophonic pilot tone signal. CONSTITUTION:A stereophonic pilot tone signal detecting circuit consisting of an LPF7, a limiter 8 and a detecting circuit 9 detects a stereophonic pilot tone signal contained in a stereophonic subchannel signal. This tone signal turns on a stereophonic indicator to show that a stereophonic broadcast is being received. When the tone signal from the circuit 9 is not detected, the stereophonic indicator does not turn on, showing that a monaural broadcast is being received. |
