| 摘要 |
A system for providing gray scale modulation signals to the drive circuit of a laser printer having a source of printer video timing signals, a printer video drive circuit, a memory for storing a raster bit map that can be read out in accordance with the timing signals, and a source of flag signals. The system includes another memory for storing a plurality of multibit bytes each encoding a corresponding gray scale value, and an address generator for relating the timing of the operation of the system to the timing of operation of said raster bit map memory. A Modulator is included for converting the gray scale values to a stream of pulse-width-modulated signals. A logic switch is included and is responsive to each flag signal for selectively feeding either the stream of pulse-width-modulated signals or the raster bit map to the drive circuit.
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