Why is CD digital data written in 44.1 kHz samples?
The rate of 44.1 kHz was picked to be compatible with existing 50 Hz and 60 Hz video-based digital audio storage, where an integral number of frame buffers could fit in a single horizontal scan. Quote from Watkinson and Rumsey, “Digital Interface Handbook” 2.7.6 Choice of Sampling Rate: “In 60 Hz [525 line, 60 Hz vertical refresh) video there are 35 blanked lines, leaving 490 lines per frame, or 245 lines per field for samples. If three samples were stored per line, the sampling rate becomes 60*245*3=44.1 kHz. In 50 Hz video [625 line, 50 Hz vertical refresh), there are 37 lines of blanking, leaving 588 active lines per frame, or 294 per field, so the sampling rate becomes 50*294*3=44.1 kHz. The sampling rate of 44.1 kHz came to be that of the Compact Disk. Even though CD has no video circuitry, the equipment used to make CD masters is video based and determined the sampling rate.” The length of 74 minutes is determined by the physical nature of the reading system. It’s based on the en
