| 摘要 |
PURPOSE:To inform an FM stereo mode with small power consumption by delivering a stereo mode information signal of a sound band after mixing it with a stereo sound signal for a fixed period of time when a pilot signal is detected out of a stereo composite signal or for each external inquiry signal during a stereo mode. CONSTITUTION:A signal source 21 for generation of stereo mode information sound divides a signal of 19kHz given from a 1/2 frequency divider 7 in a demodulator 1 and produces an information sound signal of an audible frequency band. If the signal of 19kHz is not supplied, said sound signal is not delivered. A timer 22 serves as a circuit that decides the output timing of said sound signal and delivers the information sound signals for a fixed period of time when a trigger signal is supplied from a trigger circuit 9 as the 1st control signal, i.e., in a stereo mode or when an inquiry signal is supplied with a key operation of an operator as the 2nd control signal. A mixing circuit 23 mixes the information sound signal with a decoding output signal and delivers them. This FM stereo mode informing device uses no display device such as a light emitting diode, etc. and therefore attains small power consumption and a low level of voltage. |
