PCM adaptor

A sampling frequency of 44.1 kHz was thus adopted for the compact disc, as at the time, there was no other practical way of storing digital audio than by using a PCM adaptor and videocassette recorder combination.

It is simplest if the same number of lines are used in each field, and, crucially, it was decided to adopt a sample rate that could be used on both PAL and monochrome NTSC equipment.

The lower ones are eliminated due to low-pass filters requiring a transition band, while the higher ones are eliminated due to some lines being required for vertical blanking interval; 44.1 kHz was the higher usable rate, and was eventually chosen.

The 1600 (and its later versions, the 1610 and 1630) used special U-matic-format VCRs also furnished by Sony for transports, such as the BVU-200B (the first model of VCR optimized to work, and sold with, the PCM-1600 in 1979),[2] BVU-800DA, VO-5630DA, and the later DMR-2000 and DMR-4000, which were based on the industrial VO-5850 and the broadcast BVU-800 video machines respectively.

These were all in essence modified versions of existing Sony U-Matic video recorders adapted for use with the 1600-series adaptors by way of disabling the chroma and dropout compensator circuits of the VCRs, which would hinder the proper recording of the monochrome-video-based digital audio data from the 1600-series adaptors if enabled.

The 1600-series were the first systems used for mastering audio compact discs in the early 1980s by many major record labels, with the final U-matic 1600-format digital audio tapes being sent to CD pressing plants to be recorded to a glass master disc used for making the replicated CDs.

Other makes and models of PCM adaptors offered on the market were the Nakamichi DMP-100, the JVC VP-100, the Sharp RX-3, the Sansui PC-X1 and the Hitachi PCM-V300.

This resulted in a higher quality digital recording with more dynamic range than what standard PCM modulation could offer.

Since DAT did not rely on a separate video cassette recorder, it was a much more portable and less-cumbersome format to use than a PCM adaptor-based system.

Despite obsolescence, hobbyists are still capable of using modern-day DVDs or Blu-ray discs as a transport medium for video-based encoding of digital audio streams.