Patent ID: 7532560

Claim:
A signal processing circuit of a compact disk drive for adjusting an input signal and transforming a data format of the input signal from analog to digital, the signal processing circuit comprising: an amplitude adjusting circuit for adjusting the amplitude of the input signal, having a first differential input end, a first differential output end and a second differential output end, wherein the first differential input end receives the input signal, the first differential output end outputs a first output signal, and the second differential output end outputs a second output signal; a control unit having a first input signal end, a first output signal end and a second output signal end, wherein the two output signal ends provide a control signal and a select signal respectively, the control signal is transferred to the amplitude adjusting circuit as an indication that the first output signal or the second output signal is issued; a peak detector circuit having a second differential input end, a third differential input end, a first select end and a third output signal end, wherein the second differential input end and the third differential input end respectively receive the first output signal and the second output signal such that the peak detector circuit evaluates an envelope amplitude of the first output signal and the second output signal as an indication of the select signal, the first select end receives the select signal from the control unit for selecting one of the first output signal and the second output signal as the indication of the select signal, and the third output signal end is coupled to the first input signal end of the control unit; and a waveform adjuster circuit for generating a digital signal having a fourth differential input end, a fifth differential input end, a second select end and a fourth output signal end, wherein the fourth differential input end and the fifth differential input end receive the first output signal and the second output signal respectively, the second select end receives the select signal from the control unit for selecting one of the first output signal and the second output signal as the indication of the select signal, and the fourth output signal is the digital signal derived according to the first output signal or the second output signal as the indication of the select signal.