Speed, Pitch and Timing Errors in Tape Recording and Reproducing

Because tape is a plastic medium driven by a capstan in a complicated rolling process, an accurate specification of “tape speed” is not simple. However, it is shown that even a complete specification of tape speed alone is not adequate to specify the pitch and timing error because changes of the recorded wavelength due to tape length changes cause additional independent timing and pitch errors of up to 1.0 %. These are significant in comparison with the NAB tape speed tolerance of ±0.2 %. Measurement techniques are also reviewed.