Akai 4000D - Page 5

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CROSS-TALK (Cross-talk between the tracks)
(TAPE)
Tape directio Tape direction
As shown in the figure, first record a 1,000 Hz sine wave
on track No.3 at + 3 VU level. Next, remove the
1,000 Hz input signal and record under a non-input
condition.
Then, playback the tape on track No.3 and No. 1
(reversed condition of tape) through the 1,000 Hz B.P.F.
(Band Pass Filter, Sensitivity:...1:1) and obtain a
ratio between the two from the following formula.
Eo
E, —E;
C = 20 log (db)
C =Desired cross-talk ratio (db)
Eo=1,000 Hz signal output level ma
E2=1,000 Hz cross-talk output level
E,=No-input signal record level BERRY
FREQUENCY RESPONESE
Oscillator
Connect the measuring instrument as in the above
diagram, and measure the frequency response in the
following sequence :
RECORD :
1) Give a sine wave of 1,000 Hz to the Line Input of
the recorder to be tested through an attenuator
from an audio frequency generator.
2) Set the Record/Playback Monitor Switch to “Rec.”
position and adjust the line input volume so that the
VU meter needle indicates “0” VU. ,
3) Under the condition described in (2), lower the
input level 16 db by means of the attenuator.
4) Record the spot frequency in the range of 30 to
25,000 Hz from the audio frequency generator.
PLAYBACK :
5) Set the Record/Playback Monitor Switch to “Play”
position.
6)
Set
the
Equalizer
Switch
on
7-1/2
or
3-3/4
position.
7)
Connect
a
V.T.V.M.
to
the
Line
output.
(V.T.V.M.
with
Millivolt
Scale)
8) Playback the tape previously recorded.
9)
Adjust
the
output
level
to
“0”
dbm
at
1,000
Hz
as
indicated
on
the
V.T.V.M.
by
the
range
selector
of
a
V.T.V.M.
10)
Playback
the
recorded
spot
frequencies
with
the
conditions
in
(9)
;
make
a
memo
of
output
level
and
plot
the
value
on
a
graph.