Recording And Playback - Sharp Rx-P1H Technisches Handbuch

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1-6. Recording and Playback
The inputted analog signal is digitized when it is recorded. In
some cases the signal is preemphasized by the analog signal! in
advance. If the signal is preemphasized with time constant of
50us/15ys, the preemphasis information is recorded also in
PCM-ID. In the playback mode it is detected to deemphasize
automatically.
The audio signal to be recorded in the standard mode of DAT is
sampled with 48 kHz and converted into 16-bit data, and then it
is divided into 8-bit (one symbol) block. After complicated
processing the data is recorded on the tape. As the two heads,
A and B, are provided, two tracks are interleaved so as to output
sound by interpolation even when one of two heads is temporarily
disabled and fails to read signals. Signals in the same track are
also interleaved. Thus, data is dispersed in the record mode, so
that drop-out damage is reduced. Moreover, the double
Reed-Solomon code, a powerful error correcting system, is
adopted. All of these functions are executed by LSI.
The digitized record signal is modulated by the proper modulation
system suited to recording media. DAT employs the 8-10
. conversion system. The 8-bit data is converted into 10-bit data
according to the specific rule, then it is recorded by NRZI
(inversion by code 1). An example is shown in Fig. 1-9. In the
playback mode the data is reproduced in the reverse order of
recording.
SAMPLING
BA
RECORDING
INTERLEAVE
Br *-O.
2
?
PLAYBACK o aneeene: ae
7
Tne error can be a
InterPolated by using
the Preceding and
fallowing data.
Figure 1-8 Interleaving method
(O O) CFF)
DATA 00000000 11111111
DATA |
WAVEFORM
CODE 0101010101/1111101 010
MODULATION | | | | LI LI | |
WAVEFORM
Figure 1-9 An example of 8-10 moduation
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