| 摘要 |
Gain control of signals processed in a digital TV receiver is split between serially connected coarse and fine gain blocks. The coarse gain block consists of bit shifters to shift the sample bits to greater or lesser significant bit positions which provides a 6 dB gain change for each bit position change. Fine gain control is performed in the digital-to-analog converters which ultimately produce the analog signals for driving the display tube. The digital-to-analog converters are selectively reset each sample period with reset pulses that are developed by a fine gain control. The output signal from the digital to analog converter is an amplitude and pulse width modulated signal. The average amplitude of the signal over a sample period is determined by the pulse width and is thus a function of the fine gain control.
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