SIGNAL PROCESSING FOR DIGITAL OPTICAL DISC PLAYERS

摘要

The dc coupled signal processor of the invention provides a method for accurately converting an analog input signal from a digital optical disc which signal has a finite rise time to a digital signal with accurately positioned edges by preserving the dc content of the input signal. A peak-to-peak detector detects the average of the peak-to-peak analog signals and feeds it to a low pass filter which operate above the periodic drift-like analog input signal. The output of this filter is employed as a reference voltage by a comparator which is used as a slicer or zero crossing detector. The comparator output is a digital signal with minimum bias distortion. The output of the filter is also fed to a differential amplifier and a second low pass filter which operates at a frequency below the cutoff of the periodic drift analog input a signal. The resulting signal is negatively fed back to the input to be summed and amplified with the input analog signal.