Akai X-2000SD - Page 5

Il.
MEASURING
METHOD
TAPE SPEED DEVIATION
1. Method involving use of pre-recorded tape.
For
measuring
the
tape
speed
deviation,
play
back
the
pre-recorded
tape
at
1,000Hz
+
0.1%.
Connect
the
appropriate
output
to
a
frequency
counter
meter
in
order
to
measure
the
tape
speed
deviation
from
the
resulting
deviation
of
the
measured
frequency.
2.
Method
involving
use
of
timing
tape.
(designed
for
tape speed measurement)
This method utilizes a timing tape marked at intervals of
7-1/2".
The
running
time
of
over
60
marked
sections
of
tape
is
measured
in
order
to
calculate
the
deviation
of
the
tape
speed.
In
applying
this
method,
however,
it
should
be
kept
in
mind
that
the
timing
tape
stretch
or
‘contract
measurement
error
is
inevitable,
so
that
it
is
necessary
to
measure
the
total
length
of
the
tape
in
advance.
WOW AND FLUTTER
Playback
the
3,000
Hz
pre-recorded
tape
of
which
the
wow
and
flutter
level
is
guaranteed
to
be
smaller
than
0.07%
for
measurement
by
means
of
a
wow
meter.
It
is
also
possible
for
a
3,000
Hz
sine
wave
to
be
recorded
and
played
for
measurement
by
means
of
the
wow
meter.
In
this
case,
however,
the
wow
meter
indicates
a
value
as
much
as
twice
the
value
given
in
the
specifi-
cations
on
the
first
page.
SIGNAL
TO
NOISE
RATIO
X-2000SD
mci
|
CE
Set the Equalizer Switch on “7-1/2” ips position and
playback a tape containing a 250 Hz sine wave recorded
at “0” VU level on a standard recorder.
Connect
a
V.T.V.M.
to
the
line
output
jack
of
the
recorder
and
measure
its
output.
Then remove the tape and measure the noise level under
the same condition. Convert each of the measured values
into decibels.
TOTAL
HARMONIC
DISTORTION
FACTOR
1 Ke/s
Audio
Oscillator
Connect
the
measuring
instrument
as
shown
above,
and
record
the
1,000
Hz
sine
wave
at
“0”
VU.
Playback
the
resultant
signal
and
measure
the
overall
distortion
factor.
Measure
the
noise
level
of
the
tape
recorder
with
the
tape
removed
;
connect
the
audio
oscillator
directly
to
_
the
distortion
meter
for
measurement
of
the
distortion
factor
of
the
oscillator.
The
required
distortion
factor
may
be
obtained
from
the
results
of
the
above
measurement
by
the
following
formula.
‘ctorti
X-2000SD
Distortion
Meter
do = d—di—d2
where, do = Required
d - = Overall distortion factor
di = Noise level
d2
=
Distortion
factor
of
the
oscillator
(Note
:
New
tape
of
particularly
good
quality
should
be
used
for
measurement
of
the
distortion
factor.)
POWER OUTPUT
Playback
a
tape
containing
a
1,000Hz
sine
wave
recorded
at
0
VU
ona
standard
recorder.
Connect
a
V.T.V.M.
to
the
line
output
jack
of
the
recorder
and
measure
the
voltage
at
the
output
of
the
recorder
to
be
tested.