Teac A-300 - Recording Performance Adjustments (Continued); Crosstalk and Dolby NR Effect Measurement

6-3-8. ADJACENT TRACK CROSSTALK
MEASUREMENT
Specification: 40 dB (min.)
NOTE:
The
tape
must
be
completely
erased
or
demagne-
tized
prior
to
this
procedure.
Numbers
in
parentheses
correspond
to
steps
in
Fig.
6-20.
1, Load a TEAC MTT-506 test tape.
2.
Apply
a
125
Hz
test
signal
at
—-9
dB
(275
mV).
3.
Place
the
deck
in
the
record
mode
for
about
30
se-
CONGS.”
Bole.
Qcsncerg
mowanan.
tgs
ed
ate
es
(1)
4.
Rewind
the
tape
to
the
starting
point
of
recording.
(2)
5.
Play
the
tape
and
measure
the
output
level
of
the
re-
corded
portion,
Note
this
reading
for
temporary
ref-
erence
level
for
the
following
measurements.
....
(3)
6.
Remove
the
test
tape,
turn
it
over
and
replace
it
in
the
De
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ees
as
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Fie
rte
Masa
beat
we
cd
vacm
ta
ace
bgen
totes
(4)
7,
Play
the
tape
back
and
read
the
output
level.
...
.
(5)
8.
Get
the
difference
between
this
reading
and
the
reading
previously
measured
for
the
125
Hz
signal.
9.
A
40
dB
difference
or
more
is
required.
record wath Side 2
(1)
(2)
(3)
Fig. 6-20 Adjacent Track Crosstalk Measurement Procedure
6-3-10. DOLBY NR EFFECT MEASUREMENT
Specifications:
Variation from reference at 1 kHz: 3dBto8dB
Variation from reference at 10 kHz: 8 dBto 12 dB
Load a TEAC MTT-506 test tape.
Apply and record a 1 kHz signal at —32 dB (19.5 mV).
Rewing and play this recorded section.
During playback, read the indication on the AC Volt-
meter and note it for temporary reference level for the
following measurement.
5. Set the DOLBY NR switch to IN.
6. Ensure the reading reduces 3 dB to 8 dB from the ref-
erence level.
7.
Apply
and
record
a
10
kHz
signal
at
—42
dB
(6.15
mV)
with
DOLBY
NR
to
OUT.
8. In the same manner as step 3 to 6, ensure the reading
reduces 8 dB to 12 dB when the DOLBY NR Switch
is set to IN.
PS
OSCILLOSCOPE
Preparations:
OSCILLATOR
DECK
under TEST
Fig. 6-19 Connection
Switch Setting:
Control Setting:
OUTPUT: Specified Setting (See 6-1-2)
LINE: Specified Setting (See 6-2-2)
MIC: Minimum
Side |
EE
meas °
(4) oO
[it
Side 2
(5)
T-466
Preparations:
Connection: See Fig. 6-10,
Switch Setting:
- BIAS DOLBY NR | MONITOR
*
Control Setting:
OUTPUT: Specified Setting (See 6-1-2)
LINE: Specified Setting (See 6-2-2)
MIC: Minimum
19