Marantz 3800 - Dolby NR Circuits: Tests and Adjustments

(5)
g3e8 8
LS
& 8
INTENSITY LEVEL IN DECIBELS ABOVE 10°°© WATTS PER SQUARE CENTIMETER
8 x
z
to 10 kHz.
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Repeat test with oscillator frequency set
Output signal level should
increase 4.5 dB (+ 1.5 dB).
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10 KHz 20 KHz
100 Hz 1 KHz
FREQUENCY IN HERTZ
Figure 2-6 Fletcher -Munson Loudness Curves
3. DOLBY NR CIRCUIT TESTS
AND ADJUSTMENTS
A. TEST EQUIPMENT
Tests and adjustments in the following para-
graphs are based on the use of the Recom-
mended Test Equipment listed in Table 2-1 or
their equivalent. Figure 2-7 illustrates the Test
Figure 2-7 Test Equipment Connection Diagram, Dolby NR Circuits
2-8
\eee/ §=AC VOLTMETER
MODEL 3800
Equipment
Connection
Diagram,
Dolby
NR
Circuits.
B. PRELIMINARY CONDITIONS
(1)
(2)
'HF BANDPASS
LOAD FILTER
Set power control equipment as follows:
Line Switch.................. OFF
Phase Switch.............. NORMAL
Wattmeter Switch................ IN
Autotransformer...... Minimum (ccw)
Set the Model 3800 controls to their OFF,
minimum, or neutral settings except as
noted for the particular test, alignment,
or adjustment:
Program
Selector..............
AUX
TAPE
COPY
»
seca
nccaava
cena
vn
Out
MODE
resi
ete
lik,
eal
bed
dens
STEREO
TAPE
MONITOR...........
SOURCE
TONE,
‘BALANCE:
5
oso
ues
Center
TURNOVER,FILTERS,
LOUDNESS
.
Out
DOLBY
“ese
hed
el
ies
cee
Oe
PLAY
VOLUME............
Minimum
(ccw)
TAPE
REC-EQ...............0.,
Out
TONE
DEFEAT................
In
RECORD
LEVEL...........
Fully
cw
PLAY
CALs
ein
dcsicoawe
wees
Fully
cow
LRMETER................,
L
(Out)
400
Hz
TONE.............
Off
(
Out)
SPEAKERS............0.0000
Out
POW
E
Pg
cence
Geeile
8
eee
hg
On
(In)
AUDIO
OSCILLATOR
DISTORTION
ANALYZER
OSCILLO}COPE