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SPX1000
CHECKS
&
ADJUSTMENTS
1
—
1
Preparation (Connections)
(1)
Connect
a
10K
ohms
load
resistor
to
each
of
the L
and R
OUTPUT
(JK103, JK104).
(2)
Set
the
INPUT
level
control to
the
MAX.
position.
(3)
Set
SW101
and
SW102
on
the
AD
circuit
board
to
the
"
+ 4"
position (depressed).
Note:
Always
monitor the output
signals
with
an
oscilloscope.
1
—2
Adjustments
1-2-1
Clipping
level
adjustment
Adjust the trimmer potentiometers
(VR102:
L-CLIP,
VR1
01
:
R-CLIP) so that the
CLIP
LEDs
on the
level
meter
are
lit
when
100Hz,
9
dBm
is
input to
INPUT
L
(JK101
),
and
that
they
are
not
lit
when
the input
level
is
8
dBm.
1-2-2 Total gain
adjustment
Apply
a
signal
of
100Hz,
0
dBm
to
the
L
INPUT
(JK101),
and
adjust
trimmer potentiometers
(VR103:
L-GAIN,
VR104:
R-GAIN)
so
that
the L
OUTPUT
(JK103) and R
OUTPUT
(JK104) outputs
signals
of
-I-
10
±0.3 dBm.
1-2-3
MSB
adjustment
Apply an
input of
approx.
100Hz,
-40 dBm
to
the
L
INPUT
(JK101),
and
adjust
VR105
(MSB)
So
that the L
OUTPUT
(JK103)
or
R
OUTPUT
(JK104) outputs
a
normal
waveform
as
shown
below.
If
the
normal
waveform
as
shown
below cannot
be
obtained,
try
varying the
INPUT
level
control
and
VR
105.
1-2-4 Offset
adjustment
With no
signal input to
the
L
INPUT
(JK101),
start
the
test
program
#
9,
and
adjust
VR
1
06
(OFF-
SET) so
that the L
OUTPUT
(JK103)
or
R
OUTPUT
(JK104) outputs
a
click
waveform
of within
±20
mVpeak.
*The
VR101
to
106
are located
on
the
AD
circuit
board.
1—3
Gain
When
a
signal of
100Hz,
-20 dBm
is
applied to
the L
INPUT
(JK101),
and
SW101
and
SW102
are set as
shown
in
the following
table,
the output
levels at
the L
OUTPUT
(JK103) and R
OUTPUT
(JK104)
shall
be
within the
range
shown
in
the
table.
SW101
SW102
Output
Level
"
+ 4"
"±4"
—
10
±1.5
dBm
b
CM
1
1
to
q
-10
±1.5
dBm
*SW101
and
SW102
are
in
the ''±4''
position
when
are
depressed
in,
and
in
the
"-20"
position
when
they
are
out.
1—4
Frequency response
When
a signal of
approx.
-
10
dBm
is
applied to the L
INPUT
(JK101), the frequency response
at
the
L
OUTPUT
(JK103) and R
OUTPUT
(JK104)
with respect
to the
1
kHz
level shall
be
within the following
ranges.
20Hz
~
5KHz
±1.0
dBm
6KHz ~ 18KHz
±1.5
dB,
22KHz
Less than
—
1
0
dBm
18
OOOLXdS
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