Werbung
Requirement
test
* Continuation
12.
External and noise
voltage ratios
tape B
Tape: Me
28
-
Dolby
off
25148.
external voltage effective
DolbyBon
254dB
oy
Dolby C on
2 58 dB
- Insert cassette
- Dolby NR off/on
- Record, start.
- Tape:
Me
curve A effective
Dolby
off
|
> 53 dB
Dolby B on
> 63 dB
Dolby C on
D2
the MPX-filter F 101/
F 201
to minimum
Test circuit 2
Set the left and right level
potentiometers (RECORD
LEVEL) such thatthe volta-
ge Vo, = 245 mV (= 0 dB)
measured attest points D1
and D2.
When increasing the recor-
ding level by 2 to2,5dB the
display segments of the
+ 3 dB display must just
light up.
f
= 315 Hz
1
V
=ca.570mV
_|- Insert Cr cassette
- Dolby off.
- Record, Start.
14. Level indicator
tape B
In
Test circuit 5
Measurements as described
under point 7.2
|
Tolerance zone of freq-
quency response
DIN 45500
|. Test cassette 448A
(3180 ys und 70 us)
Cr O, IEC Il new
Rerecord frequency re-
sponse from tape A to
tape B
Playback the just made
recording (tape B).
Load test cassette
448 Awith side A,
part 3, playback fre-
quency responce into
drive mechanism A and
a recordable Cr casset-
te into drive mechanism
B.
- Press dubbing normal:
tape A is started for
_ playback and tape B for
recording.
15. Dubbing fre-
quency response
250 Hz
6,3 kHz
5dB
7dB
40 Hz
14 kHz
Record the f = 315 Hz re-
cording, part 2 on the test
tape from tape A to tape B
Output voltage, tape B
Test circuit 1
DUBBING NORMAL:
load test cassette
448 Awith side A,
part 3, playback fre-
16. Dubbing level
recording from
tape
quency responce in-
in dubbing mode and
770mVt1dB
_todrive mechanism A
f = 630 Hz at high speed
DUBBING HIGH:
|
and a recordable Cr
(2x315 Hz high dubbing).
770 mV +1 dB
cassette into drive |
|
-
ay
mechanism B..
Playback of the re-
_cording made.
-|- Dolby off
och.
Test circuit 1
Werbung
