Pioneer Electronic Corporation

Pioneer Video Corporation

Hiroshi Otaki

Masahiro Nakajima

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 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.

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Koufu, Japan

Hiroshi Otaki