Pioneer Electronic Corporation

Universal Pioneer Corporation

Tetsuo Akiyama

Takashi Okano

Satoshi Kusano

Shigeru Yasuda

A digital frequency and phase comparator for both detecting a frequency of a digital signal and the phase thereof relative to a reference signal, wherein polarity inversions of the output phase different signal and saturated characteristics of the circuit when the phase difference succeeds a predetermined value are eliminated. The inventive digital frequency and phase comparator includes a time counter, an input holding circuit for holding a first and a second count value of the time counter at two different input timings of an input signal, a first arithmetic device for determining one of the frequency and period of the inputs signal in response to the first and second count values held by the input timing holding device, and a second arithmetic device for determining a phase of the input signal relative to a reference signal in response to a selected one of the first and second count values held in the input timing holding device.

Digital frequency and phase comparator

A system for playing back information recorded on a recording medium on which a lead-in code and a lead-out code are respectively recorded at the beginning and the end of a program area, comprises a first control means for rapidly moving a pickup device at least across the area of the lead-in code of the recording medium, a second control means for moving back the pickup means when the lead-out code is detected during the movement of the pickup device by the first control means, and means for discriminating the type of recording when the pickup device reaches the program area during the operation of the first and second control means. By this provision, a queuing time before the playback of the recorded program is shortened without a fear of omitting the program area.

System for playing back information recorded on a disk recording medium

A device for controlling recording track jump operations includes a tracking servo loop which is activated when a data detecting point is traversed from an initial recording track on a recording disk to a target recording track. Circuitry is provided for accurate compensation in the event of overshooting the target recording track. A jump signal generating circuit may also be provided to reduce the frequency of generated traverse signals from a first frequency level to a second, lower frequency level when the data detecting point is a selected number of recording tracks away from the target recording track, or to gradually reduce the speed which the data detecting point traverses the recording tracks as the data detecting point moves from the initial recording track to the target recording track.

Device for controlling recording track jump operations with over-run

A method and apparatus for operating a data recording medium reproducing device in which a pick-up device reads address data from a recording medium such as a video disc. The read off data is compared with a supply desired address data to form a signal which represents whether the present position is inside, outside, or coincident with the desired position. A sequence controller operates in response to the output of the comparison to drive coarse and fine adjustment devices which position the pick-up device successively until the desired position or a position within the vicinity of desired position is reached.

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Saitama, Japan

Tetsuo Akiyama