JVC GY-HD100E Service Manual page 76

Measuring
No. Item instruments &
Input signals
2 ME SP VCO Oscilloscope
[Error rate Self-recording
adjustment] tape
– – – A D J U S T M E N U – – –
1 0 6 . M E S P
V R D A T A
S E T D A T A
SBE waveform (abnormal)
Bright parts appear randomly on the waveform.
SBE waveform (abnormal)
Narrow pulse trains appear uniformly Brightness
is low.
Freeze the image
Value A
Error
rate
Decrease
Fig. 3.5.2 (4) Consept of the adjustment
Mode
• Self-REC/
PLAY
• ADJUST
MENU
No.102
V C O
Adjusted EVR data value
: 0 8 D F H
: 0 8 D F H
6 5 5 3 5
Error rate display
6 5 5 3 5
Fig. 3.5.2 (1) SP VCO Menu
Fig. 3.5.2 (2)
Fig. 3.5.2 (3)
Freeze the image
Value B
Value C
Adjustment
Point
VR DATA Increase
Measuring point ( * )
Adjustment parts ( - )
Adjustment level ( + )
* TP2 (SBE)
Note:
[REWRITE BOARD] • Be sure to use a brand-new tape for this ad-
- JOG dial
justment.
+ Minimum error rate,
• Be sure to clean the drum with a head clean-
which should be = 498 ing tape before adjustment.
or less (per CH) • The error rate should be mesured with the
Viterbi OFF. The Viterbi is set to OFF auto-
matically when the adjustment mode is en-
tered.
(1) Prior to the procedure below, prepare self-
(2) Select "102. ME SP VCO" adjustment.
(3) Play back the self recording tape, and decrease
Upper row : CH-1
Lower row : CH-2
(4) Increase the adjustment VR DATA little by lit-
(5) Increase the adjustment VR DATA to make
(6) Decrease the adjustment VR DATA little by lit-
(7) Calculate the intermediate value "C" between
(8) Confirm that the error rate value is 498 or
(9) Check the tolerance of adjustment. Shift the
(10) Return the adjustment value to the setting
Adjustment procedure
recording tape.
the VR DATA to make the SBE waveform ab-
normal. (Fig. 3.5.2(2)) (Pressing the [STATUS]
button simultaneously with the JOG dial var-
ies the adjustment value by ±10 steps)
tle, and define the point where the SBE wave-
form becomes normal as value "A". (Fig.
3.5.2(3))
the SBE waveform abnormal. (Fig. 3.5.2(2))
tle, and define the point where the SBE wave-
form becomes normal as "B". (Fig. 3.5.2(3))
the point A and the point B, and set the value
C. (Since the adjustment values are hex
number, use a functional computation-capa-
ble calculator or the PC calculator provided in
Accessories.)
Setting value C=(A+B)/2
less in each channel.
adjustment value against the setting value by
±60h.
Conform that the error rate is 3,000 or less in
each channel. When the error rate is over
3,000, recheck the adjustment procedure
from (4).
(For example, when the adjustment value is
"9ED", ±60h is "A4D" and "98D". So, shift the
value to "A4D" and "98D", and check the tol-
erance of error rate adjustment.)
value C, and Press the JOG dial to store the
adjustment data.
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