Distortion in disc recording systems

Signals processed im 33.3 rev/min disc recording systems suffer some nonlinear distortion at several stages of the recording and manufacturing chain. These distortions are normally considered insignificant compared to those caused by the nonlinearities of the stylus-groove interaction during playback. The nature and measurement of these playback distortions will be discussed. Measured values of distortion produced by RIAA-equalized playback systems will be presented (2nd harmonic distortion of a single-sinewave input signal, amplitude and frequency intermodulation distortion of an SMPTE two-tone input signal, and difference-tone intermodulation distortion of a CCIF two-tone input signal). The audible (and inaudible) effects of specific nonlinearities in the playback process will be demonstrated by playing music and test signals through an electronic simulator of the stylus-groove interaction.