| 摘要 |
<p>A tuning system of a television receiver includes a digital automatic fine tuning (AFT) unit for generating a digital AFT signal representing the deviation of the frequency of the picture carrier of the IF signal from a nominal frequency value. The digital AFT unit includes a counter (22) for counting cycles of picture carrier during counting intervals. A portion of the IF section, the counter and at least of a portion of the signal processing section of the television receiver are included within a single integrated circuit (13). A microprocessor (17) is coupled to the integrated circuit through a serial data bus. Under software program control, the microprocessor (1) transmits function control and counting control information to the signal processing section through the serial data bus, (2) receives count information from the counter through the serial data bus, and (3) evaluates count information to determine the deviation of the frequency of the IF picture carrier from its nominal frequency value. <IMAGE></p> |
