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STEP
2
3
4
5
ADTIJSTMENT
ITEM
R.M.S
Symmetry
V.C.A
Symmetry
ZERO
Point
Confirmation
of
ENCODER
and
DECODER
Operation
I
INPUT SIGNAL
100 Hz
-5.5 dBm
(410 mV) from
an oscillator
1000 Hz,
-5.5 dBm
(410 mV) from
an oscillator
1000 Hz,
-5.5 dBm
(410 mV) from
an oscillator
lOO0Hz,
-5.5 dBm
±10 dB from
an oscillator
TEST POINT
TP-5 (L)
TP-6 (R)
(ENCODER)
TP-3 (L)
TP-4 (R)
(DECODER)
Each
ENCODER/
DECODER
Output
Terminal
Each
ENCODER/
DECODER
Output
Terminal
Each
ENCODER/.
DECODER
Output
Terminal
I
I
ADJUSTMENT
RESULT
POINT
Observe TP3 to TP6
VR2 50kB
with an oscilloscope,
(ENCODER)
and adjust with VR2
and VR4 (50 KB) so
VR450kB
that the peak value of
(DECODER)
the waveform becomes
constant at 200 Hz.
VRI 50 kB
Adjust VRI (encoder)
(ENCODER)
and VR3 (decoder) so
that the distortion at
VR3 50kB
each terminal is mini-
(DECODER)
mized (below 0.1%).
YRS 500 kB
Adjust YRS (encoder)
and VR6 (decoder)so
(ENCODER)
that the output level of
each output terminal
corresponds to the in-
VR6 500 kB
put at -5.5 dBm (410
(DECODER)
mV).
Make sure that during
encode and decode,
compression and ex-
pansion are made in
Confirmation
the proportion of 2
to 1, when the input
signal level is changed
by ±10 dB. (See Fig.
9-8)
---T -
PEAK VALUE
______ J_
1
5ms
1
~200Hz--;;,.f
Fig. 9-7 Oscilloscope Waveform
dBx NR P.C.B
V.T.V.M
OSCILLOSCOPE
,~,
TP3
to
TPS
11\f'v
I
IN
OUT
Q
,...
-
-
-
-
-
~
-
-
-
Fig. 9-8
REMARKS
Refer to Fig.
9-7.
See Note 4.
Fig. 9-8
Refer to Fig.
9-8.
INPUT LEVELS
ENCODER OUTPUT LEVEL
DECODER OUTPUT LEVE, L
-15.5 dBm
-10.5 dBm
-25.5 dBm
-5.5 dBm
-5.5 dBm
-5.5 dBm
+4.5 dBm
-0.5 dBm
+14.5 dBm
*
Tolerance of each output is ±3 dB.
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40
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