Optical disk signal conversion with peaking compensation

An optical signal conversion apparatus for converting an RF input signal read from a disk into an EFM signal, said apparatus comprising:

• a high frequency extraction portion for extracting a high frequency component of said RF input signal and for outputting the same as a conversion signal;
• and
• a slice portion for slicing said conversion signal by a predetermined level and for outputting the sliced signal,
• wherein an amount of current supplied or sank in said slice portion is variable according to a multiple speed signal.

A peaking detection circuit for detecting peaking of an RF input signal read from a disk, said circuit comprising:

• a bottom envelope detector for amplifying said input signal and outputting the same if said input signal is greater in voltage than a predetermined reference voltage, and alternately, if the input signal is lower in voltage than the predetermined reference voltage, outputting said reference voltage;
• an envelope hold circuit which responds rapidly to rise of the output signal from said bottom envelope detector and slowly to fall of the output signal from said bottom envelope detector;
• and
• a comparison portion which compares the output signal of said bottom envelope detector with an output signal from said envelope hold circuit.

An optical signal conversion apparatus for converting an RF input signal read from a disk into a conversion signal, said apparatus comprising:

• a high pass filter for filtering a high frequency signal from said input signal and for outputting the filtered signal and for varying differentiation time according to a control signal;
• a comparator for receiving the output filtered signal and for generating a conversion signal by slicing the received signal by a predetermined level by comparing the output filtered signal to a slicing level;
• a peaking detector for detecting a peaking period according to run-length of the conversion signal output from said comparator and for generating the control signal which is applied to said high pass filter during the detected period;
• and
• a slicing level generator for generating a slicing level according to a direct current level of said conversion signal.

An optical signal conversion apparatus for converting an RF input signal read from a disk into a conversion signal, said apparatus comprising:

• a high pass filter for filtering a high frequency signal from said input signal and for outputting the filtered signal;
• a comparator which compares the output filtered signal and a slicing level and generates a conversion signal by slicing the received signal by the slicing level;
• a peaking detector which detects a peaking period according to run-length of the conversion signal output from said comparator and generates a control signal during the detected period;
• and
• a slicing level generator which selects, according to said control signal, one of said conversion signal and an asymmetric signal held from a previous period and generates a slicing level provided to said comparator.

An optical signal conversion apparatus for converting an RF input signal read from a disk into a conversion signal, said apparatus comprising:

• a high pass filter for filtering a high frequency signal from said input signal and for outputting the filtered signal, said high pass filter adapted for varying differentiation time according to a control signal;
• a comparator which compares the output filtered signal and a slicing level and generates a conversion signal by slicing the received signal by the slicing level;
• a peaking detector which detects a peaking period according to run-length of the conversion signal output from said comparator and generates a control signal during the detected period;
• and
• a slicing level generator which selects, according to a control signal, one of said conversion signal and an asymmetric signal held from a previous period and generates a slicing level provided to said comparator,
• wherein said control signal of said peaking detector is provided to said high pass filter and said slicing level generator.

A peaking detection apparatus for detecting peaking at an RF input signal read from a disk, said apparatus comprising:

• a comparator for receiving said RF signal and for generating a conversion signal by slicing the received signal by a predetermined level;
• a first plurality of flip-flops triggered by a clock signal and in which the conversion signal is input to data terminals and reset terminals thereof;
• a second plurality of flip-flops triggered by said clock signal and in which an inverted signal of the conversion signal is input to data terminals and reset terminals thereof;
• and
• a selector which selects one signal of the outputs from said first and second flip-flops and generates said control signal,
• wherein said peaking detector detects a period in which run-length of the conversion signal output from said comparator is greater than a predetermined length and generates the control signal during the detected period.