| 摘要 |
A tuning system for a television receiver includes a phase locked loop (PLL) (5, 19, 21, 23, 25, 27, 29) and an automatic fine tuning (AFT) means (41) which are selectively enabled to operate to tune the receiver to nonstandard as well as standard radio frequency (RF) carriers which may be provided by cable and master antenna systems. After the selection of a new channel (CHANGE), the operations of the PLL and AFT configurations are sequentially enabled by a mode selection means (43). A first counter means (19, 21) causes said PLL means to tune an RF carrier associated with a selected channel. Signal processing means (11) are responsive to the RF carrier for producing an information response and second counter means (53, 59) are responsive to the sequential enabling of said PLL and AFT means a predetermined number of times to inhibit said information response. A channel selection means (35) may step the tuner to the next channel, or in another embodiment the receiver may be switched off. <IMAGE> |
