Pioneer Electronic Corporation

Yoshihiko Watanabe

Toshiyuki Kimura

Akira Haeno

Susumu Niinuma

Fumihiko Yokogawa

Yoshio Aoyagi

Hiroyuki Hirano

Keiichi Matsumoto

Takashi Sato

Minoru Yoshioka

Youichi Ogawa

Yoshiro Nishi

Hiroyuki Abe

Takayuki Iijima

Akio Namiki

Yoshiro Aoyagi

Tsuneyoshi Nagashita

Isamu Nomura

Kimito Kobayashi

Isao Matsumoto

Kazuto Shimokawa

Susumi Niinuma

A method of operating a disk player that reproduces information recorded on a disk. Programs on the disk are addressed from a directory in a memory and the programs are sequentially accessed according to the order in the directory. The directory can be filled by inserting random numbers or by scanning through the programs or over the tracks. A table of contents at the beginning of the disk is read if possible. The tracks can be scanned and only tracks having new programs are reproduced. Also a playback position servo operates with a dead-zone in the drive voltage.

Record information reproducing method with content identifiers

A disc player comprising a signal pickup unit to read information from a disc on which program information including address information is recorded, the signal pickup unit being movable with respect to the disc, pickup drive means to drive the pickup unit for movement with respect to the disc, and a control circuit including an address memory for storing the newest one of the addresses read from the disc, a counter operative to count addresses at predetermined time intervals for producing a signal representative of an expected address indicative of the position to which the pickup unit is expected to move in the next, the expected address being updated at predetermined time intervals, a detector circuit to produce a signal each time a discrepancy is found to exist between the newest address and the expected address. In response to the signal from the detector circuit, the pickup drive means is actuated to drive the pickup unit for movement to the position dictated by the newest address or the expected address.

Automatic loading disc player

An automatic disc player including a housing, disc carrier means to convey a disc between predetermined playback position and a predetermined withdrawal position ready to be withdrawn out of the housing upon termination of plaback operation, signal generating means for producing control signals to be predominant over various steps of the playback operation, and an electric control circuit responsive to the control signals to control the various steps of the playback operation, the signal generating means comprising position detecting means responsive to movement of the disc to the withdrawal position and operative to produce a signal when the disc being moved away from the playback position reaches the withdrawal position, and playback re-start switch means which is operative to produce a signal in response to slight movement of the disc from the withdrawal position toward the playback position, the control signals to be produced by the signal generating means including signals to control the start of playback operation. The position detecting means and the playback re-start switch means are connected in series with between ground and the control circuit, and the signals to control the start of playback operation include the signal from the playback re-start switch means.

A pulse-width modulation drive circuit for a load such as a motor, particularly, a motor used in a compact disc player or the like, in which losses in diodes used to absorb reverse EMF are substantially eliminated. For this purpose, the pulse widths of pulse signals used to on-off control drive current flow through the load are controlled so as to eliminate the diode losses. The circuits of the various embodiments of the invention are designed so as to be easily implemented in integrated circuit form.

Pulse-width modulation drive circuit

An automatic disc player including a housing, disc carrier means to convey a disc between predetermined playback position and a predetermined withdrawal position ready to be withdrawn out of the housing upon termination of playback operation, signal generating means for producing control signals to be predominant over various steps of the playback operation, and an electric control circuit responsive to the control signals to control the various steps of the playback operation, the signal generating means comprising position detecting means responsive to movement of the disc to the withdrawal position and operative to produce a signal when the disc being moved away from the playback position reaches the withdrawal position, and playback re-start switch means which is operative to produce a signal in response to slight movement of the disc from the withdrawal position toward the playback position, the control signals to be produced by the signal generating means including signals to control the start of playback operation. The position detecting means and the playback re-start switch means are connected in series with between ground and the control circuit, and the signals to control the start of playback operation include the signal from the playback re-start switch means.

Growing community of inventors

Kawagoe, Japan

Yoshihiko Watanabe