| 摘要 |
An automatic tuning system for a television receiver. A first binary-coded signal circuit comprising a plurality of comparators for encoding in a binary signal a signal output from a frequency discriminator is provided together with a second binary-coded signal circuit for encoding in a binary signal the presence and absence of a synchronizing signal in a signal from a synchronizing separation circuit and a signal from a deflector circuit. The first binary-coded signal circuit is connected to two first logic circuits, two flip-flops and a differentiating circuit, while the second binary-coded signal circuit is connected to two second logic circuits, two flip-flops and a differentiating circuit. Each of the flip-flops is reset by the output signal from the logic circuits actuated by said both binary-coded signals, and is set through a plurality of channel selecting switches operated by associated channel selecting buttons. A tuning voltage generating circuit is provided which comprises a high impedance amplifier and an integrating circuit. With such circuit arrangement, the tuning voltage applied to an electronic tuning type tuner is so controlled in dependence on the signal produced upon actuation of the channel selecting button that an optimum voltage level is automatically produce to thereby assure that a broadcast signal of the selected channel can be received in a constantly stabilized manner.
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