Digital Audio Recording on Videotape: Some Choices

In concise form, some aspects of digital audio recording on videotape are discussed. It may be important for the specialist to know, in the next few years, answers to some related questions. Digital audio recording is briefly compared with bias (analog) audio recording. The essential elements of a digital recording system are mentioned; its accuracy is proportional to the number of bits available to measure a signal; its dynamic range is given by a multiple of this number plus a constant. Four methods for the digitization of an audio signal are described: linear digitization, nonlinear companding, floating point, and near-instantaneous companding. Sampling rates and their influence on bandwidth and interfacing are discussed. Alias components must be avoided, and the dc components of the signal must be suppressed or accommodated. In designing digital audio recording equipment, not only must there be given careful consideration to the physical arrangement of the recording heads and the corresponding track placement on the tape, but also to the concealment and correction of errors within the bit stream. General agreement on design practices will make recorders of various manufacturers freely interchangeable.