| 摘要 |
PURPOSE:To improve performance of a small-sized television, by detecting that there is no synchronizing signal, turning off a part of an electric power supply of a sound circuit with a controlling circuit, and stopping a noise output from a loudspeaker. CONSTITUTION:Picture and sound waves from a receiving antenna 1 are provided to a tuner 2 of a picture system circuit 4, a signal processed by the tuner 2 is applied to a picture amplifying circuit 3, and an output of the circuit 3 is fed to a CRT5. Also, an output of the circuit 3 is inputted to a synchronizing system circuit 8, a synchronizing signal is fetched by a synchronization separating circuit 16 of this circuit 8, this fetched synchronizing signal is inputted to a controlling circuit 17, and while the synchronizing signal is inputted in the circuit 17, the voltage is applied to a part of a sound system circuit 6, and while the synchronizing signal is not inputted, the voltage applied to a part of the circuit 6 is cut off. Also, an output of the circuit 8 is supplied to a deflection system circuit 10, and it is fed to a variable resistance 14 through a boosting circuit 9, the voltage applied to a variable cap of the tuner 2 is changed so as to tune with a desired channel, and generation of a noise in a non-tuning period is prevented. |
