| 摘要 |
PURPOSE:To reduce a noise spectrum in a reproducing signal by recording a digital sound signal modulated by PSK system for each system of offset poly-phase PSK into the deep layer of a magnetic layer together with a high frequency bias signal. CONSTITUTION:Right/left channel analog sound signals incoming to terminals 31a, 31b is converted into a PCM sound signal by A/D converts 34a, 34b and given to an offset PSK modulator 36 via an encoder 35. The modulator 36 outputs a digital sound signal being the result of four-phase PSK modulation to the inputted digital sound signal. The resulting sound signal is subjected to band limit by a band-pass filter 37 and fed to a bias superimposition circuit 39, where the high frequency bias signal is superimposed thereupon. The superimposed signal outputted from the circuit 39 is subjected to a high frequency bias recording up to the depth of the magnetic layer of the magnetic tape 43 driven by sound rotary heads 41a, 41b to form a sound track. Thus, the reproduced noise spectrum caused by intermodulation distortion due to nonlinearity of the tape 43 is drastically reduced.
|
