| 摘要 |
A helical-scan video tape recorder (VTR) records time-axis-compressed PCM audio signals on auxiliary recording tracks on a recording medium and has a synthesization circuit which mixes normal frequency-modulated audio signals (AFM audio signals), recorded on video tracks with video signals, with the time-axis-compressed Pulse-Code-Modulated audio signals (PCM signals) before reproduction through speakers. The PCM audio signals require digital processing for time-axis compression, and so are recorded and reproduced later than the AFM audio signals. Thus, when reproduced, the PCM audio component lags behind the AFM component, resulting in an echo effect. Adjustment of the relative amplitude levels of the two types of audio during synthesization produces acoustical effects that simulate the acoustics of a concert hall.
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