Denon DR-M22 - Mechanism Operation and Control; Mechanism Control Microcomputer Overview

e
Outline
of
the
Mechanism
Control
Microcom-
puter
The
function
of
the
microcomputer,
which
is
applied
to
the
uni-directional
transport
cam
drive
control
cassette
deck
mechanism,
will
receive
an
outside
signal
from
the
opera-
tion
switch
(operations
such
as
PLAY,
REC,
STOP,
FF)
during
the
recognition
of
the
current
condition
or
from
the
surrounding
circuits
of
the
microcomputer
(counter,
cam
encoder,
reel
pulse,
etc.)
and
sends
the
appropriate
con-
trol
signal.
To
the
mechanism:
rotational
direction
of
the
ree!
motor,
speed,
stop,
rotational
direction
of
the
cam
motor,
stop.
To
the
counter:
makes
an
output
of
the
mechanism
run
mode
command
(REW,
FF,
PAUSE,
PLAY).
To
the
display:
REC,
PAUSE
(REC
MUTE
during
flash).
In
addition,
the
following
points
are
taken
into
consider-
ation.
Counter
(micro-
computer)
Operation
key
Timer circuit
mechanism
control
(micro-
computer
Cassette
deck
(1)
(2)
(3)
Stable
and
accurate
cam
rotation
position
control
is
required
since
a
cam
drive
method
is
employed
to
make
the:
mechanism
silent.
Accurate
rotation
position
control
is
performed
by
using
a
cam
drive
with
a
rotary
encoder
detected
digital
feedback
servo.
Since
the
leading
time
of
the
cam
drive
is
slower
when
compared
to
that
of
the
plunger
method,
problems
will
arise
when
attempting
record/playback
or
stop
at
the
designated
tape
position
from
FF
or
REW,
since
tape
overrun
Occurs.
Overload
measures
of
the
cam
\f
the
cam
stops
due
to
an
overload
for
any
reason
and
cannot
shift
to
the
target
position
within
4
seconds,
it
is
immediately
shifted
to
STOP.
If
this
cannot
be
shift-
ed
within
4
seconds,
the
microcomputer
will
stop
all
controls
and
stop
the
motor
to
prevent
a
breakdown.
Audio
record/
playback
amplifier
(my
Take
up
reel
(-)
Reel pulse