| 摘要 |
PURPOSE:To achieve accurate channel selection, by providing a synchronizing separation circuit picking up a horizontal synchronizing signal of a TV broadcast signal independently with a CRT deflection circuit, and stopping the sweep of the tuning voltage through the detection of the coincidence between the picked-up horizontal synchronizing signal and deflection pulses. CONSTITUTION:A synchronizing separation circuit 1 is exclusively provided with an electronic channel selector, and only horizontal synchronizing signals are separated and picked up from a TV broadcast signal. The coincidence between the phases of the picked-up horizontal synchronizing signal and the deflection pulse formed at a horizontal scanning deflection circuit 2 of a TV receiver main body side is detected at a coincidence detection circuit 3. The detected signal is smoothed at a capacitor C1 and applied to an electronic tuner 4 to stop the sweep of a tuning voltage. With such constitution, no coincidence detection signal is outputted from the circuit 3 due to noise, allowing sure channel selection. |
