Digital time base corrector

A digital time base corrector comprising:

• A/D converting means for sampling a color video signal which was read out and reproduced from a recording medium and for converting said color video signal into a digital signal;
• polarity data generating means for generating polarity data indicative of a polarity of a burst signal from said digital signal at every horizontal scan period;
• an image data memory for storing said digital signal as image data on a sample unit basis at every horizontal scan period;
• a subcarrier phase memory having memory locations of said polarity data of the number as many as only the number of said image data to be written into said image data memory;
• memory control means for controlling writing of said image data at memory locations in said image data memory which are sequentially designated in accordance with a write clock signal whose phase is synchronized with a time base fluctuation included in said color video signal, for controlling writing of said polarity data at memory locations in said subcarrier phase memory which are sequentially designated in accordance with said write clock signal, for controlling reading of said image data from the memory locations in said image data memory which are sequentially designated in accordance with a read clock signal of a predetermined period, and for controlling reading of said polarity data from the memory locations in said subcarrier phase memory which are sequentially designated in accordance with said read clock signal;
• latch means for holding and outputting said polarity data read from said image data memory during a reading operation period of said memory control means corresponding to a horizontal scan period in which said polarity data is generated by said polarity data generating means;
• first discrepancy detecting means for generating a first discrepancy detection signal when a discrepancy between said polarity data read out by said memory control means and the polarity data held in said latch means is detected;
• second discrepancy detecting means for generating a second discrepancy detection signal for a new horizontal scan period when it is detected that said memory control means is not shifted to a data writing operation in said new horizontal scan period in the case where said memory control means starts a data reading operation from said image data memory and said subcarrier phase memory for said new horizontal scan period;
• color phase inverting means for relaying said image data read out by said memory control means, for inverting a color phase of said image data read out by said memory control means in accordance with said first or second discrepancy detection signal, and for relaying said color phase inverted image data;
• and
• means for generating an analog video signal on the basis of said image data which is outputted from said color phase inverting means.