Gx-Fsl Auto Tuning Block Diagram - Akai GX-F31 Service Manual

Ill. DESCRIPTION OF GX-F51
1. OUTLINE OF GX-FS 1
AUTO TUNING SYSTEM
When the test switch is set to STOP position, the
microprocessor sets the mode to FF for 64 counts,
the leader tape is avoided and REC mode is set.
While changing the bias by variation of 3 bits 8 steps,
the standard input of l kHz/IO kHz is recorded in
one step. When 8 steps are completed, the tape is
rewound and the point where the level of
1
kHz is
equal to that of IO kHz is picked up as a bias setting
point. If there is no equal point, the same process is
repeated and a point with minimum difference
between 1 kHz and 10 kHz is picked up as the setting
point. The variable range is ±20%.
Next I kHz signal is record at 8 different levels
2. GX-FSl AUTO TUNING BLOCK DIAGRAM
Reh
AUDIO SIGNAL-------=-1
REC LEVEL
ADJ
MUTE SIGNAL
N N
2 2
Q
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w
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w
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3 bit
CIRCUIT
(8 steps). Then the tape is played back and the
recording sensitivity level is set at the level equal to
the reference input level (-20VU). If there is no level
equal to the reference input level, recording & play-
back will be carried out again and the recording
sensitivity level will be set at the level closest to the
reference input level. The variable range is -3 dB to
+4 dB. By changing the bias, frequency characteristics
I kH/10 kHz can be adjusted and by setting
REC/PB
levels, the fluctuation of frequency characteristics
can be absorbed when, for instance, using Dolby-C
type, etc. The contents of tuning is not changed
unless REF is depressed or the tuning is repeated
again.
GX-F51 should set nearest to REF without indication
of errors.
REC EO AMP
REC BIAS
CIRCUIT
REC HEAD
1------~--
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ERASE HEAD
- - ~ x
..._-..... --.--,...--....1
3 bit
AUTO TUNING Ml -Com MB8843M
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MECHANISM
CONTROL Mi-Com
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Fig. 4
1-9