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CRS-2104
6.7 MEASURING THE COMBINED RECORDING
AND PLAYBACK LEVEL
Connect
a 1 kHz, —60 dBV
signal from an audio-fre-
quency
oscillator to the external
mic jack and record
it. In turn, play the recorded signal back. Read the signal
level at the terminal J701
or J801. The normal
signal
level will be 0.775 V rms.
AF
Unrecorded
Recording
Tape
Attenuator
Mode
Recorded
Portion
Playback
J701, J801
6.8
MEASURING THE COMBINED RECORDING
AND PLAYBACK DISTORTION
Record and playback a signal in a manner similar to that
for Item 6.7 above. Measure the distortion.
6.9
MEASURING THE COMBINED RECORDING AND
PLAYBACK SIGNAL-TO-NOISE RATIO
Record a signal in a manner similar to that for Item 6.7
above.
Rewind the tape a little. Make the external mic
jack short using a short plug and erase a part of the re-
wound
tape. Read the signal level for the 1 kHz, —60
dBV
input and the noise level for the erased part. Sub-
tract the noise level from the signal level in dB.
Short
Plug
Playback
Mode
MIC Jack
Recorded
Portion
fe
Recording
Mode
J701, J801
10
6.10 MEASURING THE ERASING LEVEL
Connect a 1 kHz bandpass filter to the terminal J701 or
J801. Playback the tape used in Item 6.9 above.
Con-
nect a 1kHz, —60 dBV signal from an audio-frequency
oscillator to the external mic jack and record it. In turn,
play the recorded
signal back.
Read the signal level in
reference to OdB.
Record
a 1 kHz, —50 dBV
signal in
a manner similar above and rewind it. Make the external
mic jack short using a short plug and erase the rewound
tape. Play the erased portion back and read the signal
level for the 1 kHz, —60 dBV signal.
Recorded
Portion
Playback
100 kQ
1 kHz Bandpass
Filter
J701, J801
6.11 CALIBRATING THE VU METER
Connect a precisely-adjusted 6.75 V DC power source to
the DC 9V Jack. Set the recorder in the playback mode.
Adjust R356 so that the meter reading is between the
black and green areas of the scale.
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