Atari 1010

1010S LIMITER
The
3995Hz
and
5327Hz
signals
from
the
Data
Amplifier
are
not
always
equal.
The
Limiter
equalizes
and
amplifies
them.
Signals
are
converted
to
FSK
(Frequency
Shift
Key).
The
limiter
also
restricts
men
input
by
gauging
the
amount
of
feedback
at
the
turn-on
point
of
diodes
D4
and
D5.
The
characteristics
of
the
filters
are
listed
below:
5327Hz Filter 3995Hz Filter
Center Frequency 5435Hz Center Frequency 4092Hz
Qe
3.433
Q
3.479
Gain 2.206 Gain 2.20
1010S ENVELOPE DETECTOR
Envelope
detectors
exist
for
both
the
limiter
filters.
Starting
time
for
both
is
approximately
0.15
us,
and
discharging
time
approximately
1.27
us.
Since
discharging
time
for
both
filters
is
longer
than
the
turn-on,
by
approximately
a
factor
of
10,
the
ripple
generated
at
3995Hz
and
5327Hz
must
be absorbed.
1010S OUTPUT STAGE
The
Output
Stage
consist
of
two
low-pass
filters.
The
starting
time
of
the
Output
Stage
coincides
with
the
transfer
rate
of
the
cassette
interface
at
600
baud.
1010C ELECTRICAL THEORY
1010C POWER SUPPLY
The
1010C
power
adaptor
supplies
9
volts
AC,
which
is
converted
to
DC
by
a
bridge
rectifier.
In
early
production
units
the
power
LED
lights
as
soon
as
the
power
adaptor
is
plugged
in.
In
later
models
the
power
LED
will
only
light
after
you
press
PLAY,
REWIND,
or
ADVANCE.
1010C CIRCUIT DATA OUT
The
1010C
unit
uses
an
active
filter
network
that
segregates
the
frequency
encoded
data
into
a
comparator
Al100D,
which
then
generates
digital
data.
The
signals
from
the
READ
Head
are
amplified
and
applied
to
a
high
gain
limiting
amplifier
(A100A).
From
the
limiting
amplifier,
the
signals
are
applied
to
two
Multi-
Pole
Active
Filters
(A100B,
Al100C)
which
allow
differing
outputs
as
a
function
of
frequency.
Rectification
and
simple
filtering
of
the
Active
Filter
outputs
place
a
psuedo-DC
input
to
either
side
of
a
comparator.
Finally,
the
output
of
the
comparator
is
filtered
and
applied
to
a
Driving
Transistor
Inverter
(Q103),
which
drives
the
Data
Line
to
the
computer.
The
1010C
receives
its
power
(+5v)
from
the
power
supply
of
the
Atari
Computer.
ATARI 1010 Cassette Recorder 1-2