Channel Separation . S I L Aces; Crosstalk Between Adjacent Tracks - Teac A-400 Service Manual

4-3-9. Channel Separation
The ratio should be: 30 dB (minimum)
NOTE
To check cross talk, a 1 kHz narrow bandpass filter should be
used. The test signal delivered from an AF oscillator should be
tuned to the filter used.
ATTENUTOR |
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Oe @®,
OSCILLATOR
DECK
under TEST
OUTPUT
{R)
IkHz FILTER
Record 30 seconds of a 1 kHz signal.
3. Load a TEAC MTT-505 test tape on the deck.
Place the BIAS/EQ switches to 1" positions.
>
4-3-10. Crosstalk between Adjacent Tracks
"The ratio should be: 40 dB (minimum)
=
through an attenuator.
Connect a VTVM to the right channel OUTPUT jack.
Load a TEAC MTT-505 test tape on the deck.
Place the BIAS/EQ switches to the ''1" positions.
Make a recording of 30 seconds of a 125 Hz signal.
ONE
2
4-3-11. Dolhy NR System Efficiency Checks
The variation at 1 kHz should be: 5.5 dB +2.5 dB
The variation at 10 kHz should be: 10 dB +2 dB
' attenuator.
2. Connect a VTVM to the OUTPUT jacks.
Load a TEAC MTT-505 test tape on the deck.
DOLBY NR switch to the OUT position.
Apply a 1 kHz signal at -29 dB (27.4 mV).
Record this signal.
Rewind the tape to the starting point of the recorded. section.
Play this recorded section of the tape.
While playing the 1 kHz signal, read the indication of the
output level on the VTVM with the DOLBY NR switch at IN
_ and OUT positions.
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20
10.
ATTENUATOR
OSCILLATOR
DECK _
under TEST
T+ 393
Fig. 47 Crosstalk Check Setup
NOTE
11.
12.
OSCILLATOR
OSCILLOSCOPE
DECK
under TEST