Image generating system for laser photocopier, printer - has solid state laser output pulse width modulated using phase locked loop using analogue voltage controlled oscillator

摘要

The image generator has a solid state laser (1) that has an output that is pulse width modulated by video data generated by a selector receiving inputs from a number of look up tables. The modulation process is provided by pulse generation logic that is coupled into a phase locked loop, PLL. The loop is formed with an analogue voltage controlled oscillator, VCO that receives a reference voltage (VREF) from a phase comparator coupled to a low pass filter. The modulated laser beam is reflected as a scanning beam by a rotating polygonal mirror. ADVANTAGE - Cost effective. Handles broad range of frequencies.