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3. For the level adjustment, set the DOLBY switch and SELECTOR switch to the RECORD |
and CD-4/AUX
positions, respectively, and use the TAPE
MONITOR
OUT jack for the
signal output. By setting the 400Hz TONE pushswitch "in'', the 400Hz sine wave is fed out.
Adjust the semi-fixed resistor RL11 for 580mV of the sine wave output voltage in both R
and L channels. Then, set the DOLBY
switch to the RECORD
II position, and apply the
400Hz signal for 580mV of the output voltage. Adjust the semi-fixed resistors RL28 and
RL29 so that the DOLBY LEVEL meter may point the Dolby level. Change over the METER
switch, and perform this adjustment for both R and L channels.
Next, adjust the semi-fixed resistor
RL12 for 580mV output level when the DOLBY switch is
set to the OFF position. Check the 400Hz output signal level after the adjustment of the level
setting semi-fixed resistors RL11 and RL12. The output level must be precisely 580mV since
it is a reference level of the Dolby circuit.
24.
EXPLANATION
OF THE
DOLBY
PROCESSING
CHART
This chart shows the condition of the signals available at the speakers (SPKRS) and at the
TAPE MONITOR OUT terminals as a function of different control settings.
To understand the chart refer to the symbols below:
—
Represents a signal which has not been applied to either Record or
————
Playback Dolby circuits. The relative amplitudes of all audio frequ-
encies remain unaltered at all levels.
—
Represents'a
signal which
has been processed by the Dolby
Record
/
circuit. The relative amplitude of the high frequencies is increased at
low signal levels.
—
Represents a signal which has been processed by the Dolby Playback
\
circuit. The relative amplitude of the high frequencies is decreased at
i
low signal levels.
-—
Represents a signal which has been processed by both the Record and
the Playback Dolby circuits.
These circuits are complementary. Therefore, relative amplitudes of all audio frequencies are
restored to their original values.
12
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