3-3
3.1.2 Error Rate of DVC
The error rate of the DVC is shown by the average number of error corrections by the inner parity in the
AUDIO/VIDEO sector (A/V inner errors) per 1 second (300 tracks). Error correction is carried out by the
ECC inside the DV-DSP IC, and the ECC outputs Error Flag SBE (Sync Block Error). The SBE is
classified into 7 levels from 0T pulse to 12T pulse according to number of error connections, and it is
output for each of 14 sync blocks of the AUDIO sector and 149 sync blocks of the VIDEO sector. For
evaluating the error rate actually, all SBE pulses that were output in 1 second are weighted by a certain
method and the total of the weighted SBE's is used as the DVC error rate.
0T: Sync failuer
2T: Error free
4T: 1-error correction
6T: 2-error correction
8T: 3-error correction
10T: 4-error correction
12T: Correction-disabled
1T=18MHz 1clock
Weighting
for SBE
0
0
1
2
3
4
5
Fig. 3-1-4 Particulars of SBE
The error rate jig in its infancy shows the total of weighted data of input SBE's by a frequency counter.
However, the error rate of the recent DVC models (GR-DVM5 and after) is output by the TCCS and can be
shown on the display of a personal computer by use of the Service Support Software (SSS).
Graph showed a change in
the Error Rate visually
White line: CH1
Pink line: CH2
Green line: 500 reference
Percentage of sync block
counting in Audio/Video
sector
Numerical value of Error
Rate
Fig. 3-1-5 Error Rate window in SSS
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