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aoe)
5-8. TAPE SPEED:
To check tape speed, use test tapes MTT-111
(1-7/8 ips) and MXT-111 (3-3/4 ips) on which a
3-kHz signal is recorded with high accuracy or
their equivatents.
1) Connect a frequency counter to the OUTPUT
terminals as shown in Fig. 5-8.
-
oe
2) Play the test tape from the start of the tape
and check that the frequency counter reading
is within 3 kHz +0.5 %
3) if the reading is outside this range, clean the
tape path and check the pinch roller pressure
and takeup tension.
_
4) If these values are correct, adjust.the resistor
of the motor so that the reading is within the
range 3000 Hz +5 Hz.
NOTE: Adjust tape speed. after the tape has run
for about 30 sec in the reproduce mode.
HIGH
STANGARD
5-9. WOW AND FLUTTER
Before measuring wow and flutter, the following
points should be read carefully. It is necessary to
decide which of the two measurement methods
should be used.
1) Reproduce
method:
Measure
while playing
wow & flutter test tapé MTT-1117, MXT-111
or its equivalent.
Record/reproduce
methed:
Record -a 3-kHz
signal on blank tape, rewind the tape and re-
produce the recorded signal.
NOTE:When
measuring
using the record/re-
produce
method,
the recorded
section
should
be
reproduced
repeatedly
to
obtain the mean value. Be careful not to
read
the meter for those parts of the
tape in which wow & flutter components
in recording and reproducing cancel each
other.
2) Set the flutter meter controls to the required
standard.
Select
the
DIN/IEC/ANSI
peak
~
value or the NAB
RMS
value, then set the
weighting control as required.
3) Measure at the beginning and the end of the
tape. The measured value will differ slightly
according to the measuring
method and in-
strument used, Standard values are:
1-7/8 ips:
+0.0B5 % peak (DIN/IEC/ANS!I weighted)
+0.1B8 % peak (DIN/IEC/ANSI unweighted)
0.06 % ©
(NAB weighted)
0.11%
(NAB unweighted)
3-3/4 ips:
+0.055 % peak (DIN/IEC/ANSI weighted)
+0.13 % peak
(DIN/IEC/ANSI unweighted)
0.04 %
(NAB weighted)
0.07 %
(NAB unweighted)
NOTE: Measure
after cleaning
the tape path,
especially the capstan shaft,..pinch-roller
and head surfaces.
OSCILLATOR
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