Video signal storage apparatus for ntsc system

Abstract

A television video signal storage apparatus for storing an NTSC digital chrominance signal so as to facilitate further processing thereof. The signal is sampled at a sampling frequency 2n times the subcarrier frequency, whereby it contains 2n data for each cycle of the subcarrier, of which n data are a first polarity portion and n data are an opposite polarity portion. The apparatus includes a first inverter for inverting the polarity of n successive data corresponding to the opposite polarity portion of the digital chrominance signal, such that all of said 2n data have the same polarity; a memory for storing the modified signal; and a second polarity inverter for inverting the polarity of the n successive data corresponding to the opposite polarity portion of the modified signal as it is read out of the memory. Thus, the signal read out of the memory corresponds to the input digital chrominance signal. The digital chrominance signal may be provided by a Y/C separator which also provides a luminance signal, the latter being stored in a separate memory. In this case, the two memories may be controlled commonly by a single address generator or may be commonly controlled by separate writing address and reading address generators. The first and second polarity inverters may be controlled for reading data into and out of the chrominance signal memory with the same phase or with different phase.