| 摘要 |
<p>On selection of a channel by means of a user input means (5, 10), a tuner (30) is coarsely tuned to that channel. If television synchronizing signals are detected by a video detector (60), the tuner (30) is fine tuned by a microprocessor (20) under the control of an AFT signal from a demodulator (50). If no television synchronizing signals are detected by the video detector (60), it is assumed that the picture carrier of the received television signal is displaced, for instance in accordance with the Harmonically Related Carrier system employed for cable television, and the tuner is caused to undergo a predetermined tuning shift, after which automatic fine tuning continues as normal. <IMAGE></p> |
