| 摘要 |
In tracks (S1, S2, ... ) which are inclined relative to the longitudinal direction of a magnetic record carrier (1) a first signal, for example a frequency-modulated audio signal, is recorded in a first layer (L1) deep in the record carrier, a second signal, for example a PCM-modulated audio signal, is recorded in a second layer (L3) which is situated less deep in the record carrier, and a video signal is recorded in a layer (L2) which is situated even less deep in the record carrier (Fig. 1). Since the PCM audio signal is subjected to an additional modulation step before it is recorded, to convert it into a QPSK (quadrature-phase-shift keying) signal, peak-to-peak amplitude variations will arise in the signal to be recorded. As this signal is recorded over the FM audio signal in the same track the reproduction amplitude of the FM audio signal will be influenced in such a way that an additional modulation noise contribution arises in the frequency-modulated audio signal being reproduced. In order to avoid this modulation noise the QPSK signal is first amplitude-limited in a limiter circuit (15) before it is applied to the write head(s) (9) during recording. |
