A field store system with single 1-Mbit field memory

A field store system that stores 6-b NTSC video signals sampled at three times the scanning frequency (3 f_sc) was developed using a single 1-Mb field memory is reported. The system uses four ICs: the single field memory, a controller, an analog-to-digital converter, and a digital-to-analog converter. The analog composite video signal is converted to 6-b digital with f_sc sampling by the analog-to-digital converter (ADC). Because the configuration used for the field memory is 4-b-wide*256 K words, a 6-4 converter converts 4-bit data read from the field memory to 6-b data for the digital-to-analog converter (DAC). The 6-b DAC converts the signal back to analog. The write/read access rate for the memory is 1.5 times faster than the ADC and DAC conversion rate. Special picture effects such as still, strobe, and search can be realized even from a video disk recorded in the constant linear velocity mode.