Pick-up device positioning arrangement in an information disc player

A pick-up device positioning arrangement for controlling a radial position of a pick-up device with respect to a turn-table in an information disc player, said pick-up device having a pick-up point to be aligned onto a target track of a disc mounted on said turn-table under control of a tracking error signal generated by a tracking servo system, said tracking error signal representative of amount of deviation of said pick-up point from said target track, said pick-up device generating an information signal, the improvement which comprises:

• an envelope detector for producing an envelope frequency of said information signal;
• a frequency to voltage converter means for producing a first detection signal representative of said envelope frequency;
• a movement direction detector for producing a second detector signal representative of the movement direction of said pick-up device by comparing in phase said envelope frequency and said tracking error signal;
• a voltage generator for producing a drive voltage having a magnitude according to said first detection signal and a polarity according to said second detection signal;
• and,
• a drive means for driving said pick-up device for relative movement radially with respect to said disc at a velocity according to said drive voltage.

A pick-up device positioning arrangement for controlling a radial position of a pick-up device with respect to a turn-table in an information disc player, said pick-up device having a pick-up point to be aligned onto a target track of a disc mounted on said turn-table under control of a tracking error signal generated by a tracking servo system, said tracking error signal representative of amount of deviation of said pick-up point from said target track, said pick-up device generating an information signal, the improvement which comprises:

• an envelope detector for producing an envelope frequency from said information signal;
• a frequency to voltage converter means for producing a first detection signal representative of the frequency of said tracking error signal;
• a movement direction detector for producing a second detector signal representative of the movement direction of said pick-up device by comparing in phase said envelope frequency and said tracking error signal;
• a voltage generator for producing a drive voltage having a magnitude according to said first detection signal and a polarity according to said second detection signal;
• and,
• drive means for driving said pick-up device for relative movement radially with respect to said disc at a velocity according to said drive voltage.

A pick-up device positioning arrangement for controlling a radial position of a pick-up device with respect to a turn-table in an information disc player, said pick-up device having a pick-up point to be aligned onto a target track of an information disc mounted on said turn-table under control of a tracking error signal generated by a tracking servo system, said tracking error signal representative of an amount of deviation of said pick-up point from said target track, means for generating an external control signal indicative of the direction of movement of said pick-up device with respect to said information disc, said pick-up device generating an information signal;

• the improvement which comprises:
• an envelope detector for producing an envelope frequency of said information signal;
• a first wave-shaper for producing a first pulse signal corresponding to said envelope frequency;
• a second wave-shaper for producing a second pulse signal corresponding to said tracking error signal;
• an edge detector for producing first and second edge pulse trains, said first edge pulse train including first edge pulses each appearing at the leading edge of each pulse of said second pulse signal, and said second edge pulse train including second edge pulses each appearing at the trailing edge of pulses of said second pulse signal;
• a change-over switch for selectively passing therethrough either one of said first and second edge pulse trains in accordance with said external control signal;
• an AND gate for passing therethrough the pulses from said change-over switch when said first pulse signal takes either one level;
• a frequency to voltage converter means for producing a detection signal representative of the frequency of said pulses passed through said AND gate;
• and
• drive means for driving said pick-up device at a velocity according to said detection signal.