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H.
MEASURING
METHOD
1. TAPE SPEED DEVIATION
3. FREQUENCY RESPONSE
As shown in Figure 1, connect a Frequency Counter
to the
Line
Output
of the recorder.
Take
a
frequency counter reading at the beginning,
middle,
and end of tape winding during playback.
The
maximum
value
of these
respective
readings will
represent
tape speed
deviation.
Fig. 3
High Sensitivity
V.T.VM.
1) Connect
the various
instruments
as shown
in
2.WOW
AND
FLUTTER
Fig. 3 and supply a 1,000 Hz sine wave signal to
the Line Input of the recorder from an Audio
Wow and
Frequency Oscillator through an Attenuator.
Set
Flutter
Meter
recorder
to "REC"
mode
and turn
recording
level control volume
to obtain "O" VU meter
Fig. 2
reading.
2) Under conditions described in 1) above, readjust
Method
A
Attenuator so that the Line Input is -16 dB, and
As shown in Fig. 2, connect the Line Output of the
record 50 to 18,000 Hz spot frequencies.
recorder to the Input of a Wow and Flutter Meter.
3) Rewind
tape and playback from the beginning.
Use a 3,000 Hz pre-recorded test tape and take a
Take V.T.V.M. spot frequency readings and plot
wow
and flutter meter reading at the beginning,
values on a graph.
fogs
middle, and end of tape winding.
The maximum
ope,
value of these respective readings will represent the
NOTE:
When measuring frequency response, new
wow and flutter.
tape should be used.
Method B
Supply a 3,000 Hz sine wave signal from an Audio
4. SIGNAL
TO NOISE
RATIO
Frequency Oscillator and make
a recording on a
Speaker
blank tape at the beginning, middle,
and end of tape
Output
Input
.
rae
Fig. 4
ad
wow and flutter value of Method B will be close to
|
2 times of Method A)
Connect the various instruments as shown in Fig. 4
and playback a 250 Hz "0" VU pre-recorded test
tape and adjust volume control to obtain +10 dbm
V.T.V.M. reading. Then remove the tape and measure
the noise level under the same condition.
Convert
each of the measured values into decibels.
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