I
122
6-8.
TAPE
SPEED
Use
the
TEAC
MTT-111 test tape (containing
highly accurate 3-kHz signals)
or
its equivalent
to
mE:asure
tape speed.
1)
Connect a frequency
counter
to
the 0
UTPUT
terminals
as
shown in Fig. 6-8.
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.
NOT
E:
Adjust
tape speed after the tape
has
run
for
about
30
sec
in the reproduc.e mode.
Fig. 6-7
6-9. 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 tape MT-111
or
its equiv-
alent.
Record/reproduce
method:
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 record ing and reproducing cancel each
other.
2) Set the
flutter
meter controls
to
the required
standard. Select
the
01
N/I
EC/ ANSI peak
value
or
the
NAB
RMS value, then
set
the
weighting
control
as
required.
3)
Measu
re
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:
±0.085
% peak
(DIN/IEC/ANSI
weighted)
±0.18
% 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.
OSCI LLATOR
WOW
/F
LUTTER
/.IETER
UNIT
[D
und
er TE S T
1"'
000i.l!PIJT"'-~---1-<>
o 0
Fig. 6-8
45
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