Pioneer Electronic Corporation

Pioneer Video Corporation

Pioneer Electric Corporation

Pioneer Electronics Corporation

Masahiro Nakajima

Tutomu Banno

Hiroshi Otaki

Tadayoshi Kobayashi

Eisaku Kawano

Hitoshi Otaki

A digital time base corrector in which a memory for correction of a time base is commonly used as a memory for correction of a drop-out and a signal process to a video signal which is replaced by a drop-out compensation is made unnecessary. The corrector has an image memory having a capacity to store the digital video signal by only two horizontal scan periods. When a drop-out occurs in the reproduction video signal, the writing operation into the image memory is inhibited. In the portion in which the drop-out occurred, the video data before about 2 H is read out in place of such a portion and the drop-out compensation is executed. Therefore, the drop-out portion is replaced by the video data of the same phase.

Digital time base corrector for reproducing video signals

A digital time base corrector uses a memory with a reduced storage capacity, to reduce the cost. Absolute value data of an amplitude and polarity data of a burst signal in a color video signal are written into a memory every horizontal scan period. A signal in which a sync signal interval, a pedestal level interval, and a burst signal interval in the color video signal are eliminated is written as image data into the memory. The absolute value data, polarity data, and image data are read out from the memory. Burst signal data is reproduced on the basis of the absolute value data and polarity data. By inserting the burst signal data, sync signal data, and pedestal level data into the image data, a color video signal is reproduced.

Digital time base corrector using a memory with reduced memory capacity

A digital time base corrector, when using a memory whose storage capacity is reduced to a value of about 1H of the video signal, can maintain an interleave relation between a luminance signal and a color signal of a video signal even when the writing operation into a memory is delayed by a jitter included in the demodulated video signal. When the read address is advanced from the write address in each of an image data memory and a subcarrier phase memory in one horizontal scan period, a discrepancy occurs between the polarity data read out from the subcarrier phase memory and the proper polarity data held in latch means. When such a discrepancy is detected, the color phase of the read-out image data is inverted. In starting the data reading operation for a new horizontal scan period, if it is detected that the operating mode has not shifted to the data writing operation for the new horizontal scan period, the color phase of the read-out image data is inverted for the new horizontal scan period.

Digital time base corrector

A digital time base corrector which can perfectly eliminate residual errors. A sync clock signal whose phase is synchronized with a time base fluctuation included in a reproduction video signal is formed in accordance with at least one of the horizontal sync signal and the color burst signal which are separated from a reproduction video signal. The sync clock signal is phase-modulated in accordance with a burst error signal indicative of the time base fluctuation of the color burst signal in a period of time other than the generating period of time of at least the color burst signal in the reproduction video signal, thereby obtaining a write clock signal of the image memory.

Digital time base corrector for video signal reproduction

A digital time base corrector reduces the capacity of a memory to approximately a 1 H of image data while maintains the interleave relationship between a luminance signal and a chrominance signal of a video signal. Polarity data indicating the polarity of a burst signal is generated every 1 H, and a latch circuit is provided for holding and outputting the polarity data during a period of reading image data and polarity data from an image data memory and a sub-carrier phase memory, corresponding to the 1 H in which the polarity data was generated. When dropout occurs in a video signal, the image data and the polarity data are inhibited from being written into the image data memory and the sub-carrier phase memory. When discrepancy is detected between read polarity data and polarity data held in the latch circuit, the color phase of the read image data is inverted.

Digital time base corrector with dropout compensating function

For a disk recording and/or reproducing apparatus which may use either constant angular velocity or constant linear velocity disks, speed compensation circuitry is provided which operates in accordance with RF signal information recorded on a surface of a disk. Irrespective of the nature of the disk being used (CAV or CLV), comparison circuitry within the apparatus provides reliable speed detection and compensation.

Disk recording and reproducing apparatus with speed compensation for CAV

A spindle servo circuit controlled according to a time base. Fine time base tuning is performed in a clock driven CCD. In a scan mode, tracks are alternately reproduced and jumped. The fine tuning is turned off at the start of jumping (which occurs after a full video field has been written into a video memory) and the center frequency of a VCO clock is decreased so as to slow the shifting of the CCD.

Scanning system in information reproducing apparatus

A time base control system for a spindle servo motor in which the time base is both coarsely controlled and finely controlled. According to the invention, when the recording head is alternately tracking and jumping tracks, the controllable range of the fine tuning is widened and the course tuning is gradually increased.

Growing community of inventors

Koufu, Japan

Masahiro Nakajima