| 摘要 |
Circuitry included in a TV receiver for enhancing the signal-to-noise ratio of the chrominance signal includes an adaptive linear phase, low pass filter which has its bandwidth controlled responsive to the upper frequency components of the current chrominance signal. A frequency analyzer coupled to the chrominance channel counts the number of chrominance signal excursions during predetermined periods to generate a number related to the maximum signal frequency during such periods. The number is applied to a decoder which generates address codes for application to a look up table which provides filter coefficients for altering the filter bandwidth in accordance with the current maximum signal frequency components. |
