| 摘要 |
PURPOSE:To attain audio multiplex recording/reproduction even in a monaural recording/reproducing VTR by converting one audio signal into a higher frequency than that of other audio signal, mixing and recording both the audio signals and restoring separately them at reproduction. CONSTITUTION:The sub audio input from a TV receiver is processed by a phase shift network PSN 306 via a changeover switch 302 of an audio multiplex sound recording adaptor 30 and an LPF 304. The input becomes a sub audio input having a phase difference of + or -pi/4, and processed by balanced modulators 309, 310 and a mixer 311 together with a signal of 9kHz or the like having a phase difference of + or -pi/4 by a VCO 312 and a PSN 308 or the like and converted into a signal having a higher band than the audio band. The signal and a major audio input from the TV receiver are mixed by a mixer 306, become an audio multiplex signal, which is recorded in a VTR. The restoration and separation of the main/sub audio after reproduction is attained similarly and the audio multiplex recording/reproduction is attained even in the monaural sound recording/reproducing VTR.
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