JVC GR-DVA10 Technical Manual page 64

Detection period
Judgment element
Threshold level and
Continuation period
Error rate conversion
∗ ∗ ∗ ∗ Note:
The threshold level of new method is decoded by data in EEPROM.
EEPROM Address: 3AEh → Data: 8Fh "10001111"
Lower 5 bits: Setting of threshold level in normal PB "01111" → 15
Value of threshold level in normal PB: 15 × 10 = 150
Upper 3 bits: Coefficient of short PB "100" → 4
Value of threshold level in short PB: 150 × 4 = 600
Above addresses and threshold levels are for GR-DVL300 series, and those may vary in the model.
4) History of head clog warning
With detection of head clog, the EEPROM counts the data and the history of head clog warnings can
be checked on the display of a personal computer with the SSS (Service Support Software).
Other specifications are as follows.
• If sync block data is read from neither of two channels for 10 continuous frames, the system
recognizes that no signal is recorded in the part and does not perform clog detection. (The cleaning
tape is recognized as a non-recorded tape.)
• Head clog detection in the short-playback mode is not performed at the first start of recording.
• Head clog detection is not performed in any mode other than the normal playback mode such as
the FF/REW, Special Playback, Audio-dubbing/Insert modes.
• Method to display marks and messages conforms to the specifications of respective models.
Previous method
(GR-DVL9800 and before)
During Short PB
at recording start
The number of Sink block counts
par 1 frame
Below 240
0.5 sec
Rough estimate: 1,000,000
Table 3-1-1 Difference of the head clog method
During Normal PB and Short PB
The value of A/V inner error par 1 frame
Normal PB
∗Over 150
7 sec
3-6
New method
(GR-DVL300 series)
at recording start
Short PB
∗Over 600
0.2 sec
Rough estimate: 10,000