DIGITAL INFORMATION REPRODUCER

摘要

PURPOSE:To control properly a threshold value by controlling the threshold value of a waveform shaping means in response to the difference between a low-frequency component of a digital signal subjected to waveform shaping and a low-frequency component of a data signal to extract the change of the low-frequency component due to an error of the thershold value. CONSTITUTION:A waveform shaping means 1 applies waveform shaping to an input signal exceeding the threshold value to give a high level output while using an output signal from a differential amplifier 5 as a threshold value and outputs a digital signal. a low-pass filter 4 extracts a low-frequency component included in a data signal and the differential amplifier 5 takes a difference of the low-frequency component between the digital signal and the data signal to detect an error of the threshold value. Thus, the output of the differential amplifier 5 is fed back to the threshold value of the waveform shaping means 1 to control the threshold value to the optimum value.