Motorola MSF 5000 Instruction Manual page 67

MSF
5000
Instruction Manual
Chapter
1
Description
68P81092E02
3/19/94
TTRC
Audio Board
Table 1-7
Wireline Configuration
2-Wire
4-Wire
Receive
"Transmit
Line
Operation Operation
Audio Audio
X 2+/-
X 2+/-
2+/-
X 1+/-
X 4+/-
3+/-
NOTE:
For proper jumper configuration,
refer to
Appendix G
-
Jumper Settings.
Non-ALC
path with
the course
level adjust circuit. Line
3
input audio is
always
sent
directly
to the
Non-ALC
path
with
the course
level adjust circuit. The system
configuration
and
RSS programming
determine whether the inputs are sent to the
ALC
or
Non-ALC
path
with
the course
level adjust circuit.
The
course level adjust
circuit
is
a
microprocessor-controlled gain stage consisting
of analog switches and an
inverting
amplifier.
The gain of this amplifier stage is
determined
by
the
combination of the two logic lines sent from
EEPOT E
on the
TTRC
Audio
board.
The
ALC
circuit consists of two gain adjust
stages.
The maximum gain of the first
stage results in
approximately
13.5
dB.
The
TTRC
Logic
board adjusts the
gain
of
this stage.
The lowest gain
of this stage is -32 dB.
The audio signal
is then routed to an inverting amplifier where it is amplified
by
a
constant
level
of 27 dB. The output (TP5) drives
the tone
processing circuitry and
is
a
source for the
TX
audio fine level adjust circuit.
The
TX
audio level adjust
stage
follows
the
ALC/Non-ALC
transmit source gate.
The transmit
source gate consists of an
inverting amplifier
and
EEPOT
7 (TX
level
adjust). Depending on the setting of
EEPOT
7,
the
gain of this stage can
vary
from
-13
dB
to -2 dB (ALC) or
-11
dB
to
10
dB (course adjust). The nominal audio level
expected at
the
output of
the
level adjust circuit
at
TP6
is
approximately
315
mV
rms.
When
both paths
are
used (Non-ALC/ALC)
in
a
console
priority configured
system,
EEPOT
7
stores
two values. One value
is for the
ALC
path; the other for
the
Non-ALC
path. Therefore,
EEPOT
7
must be adjusted twice, once while
the
ALC
path is active, and once
while
the
Non-ALC
path is active.
1-29
MSF
5000
Instruction Manual
Chapter
1
Description
68P81092E02
3/19/94
TTRC
Audio Board
Table 1-7
Wireline Configuration
2-Wire
4-Wire
Receive
"Transmit
Line
Operation Operation
Audio Audio
X 2+/-
X 2+/-
2+/-
X 1+/-
X 4+/-
3+/-
NOTE:
For proper jumper configuration,
refer to
Appendix G
-
Jumper Settings.
Non-ALC
path with
the course
level adjust circuit. Line
3
input audio is
always
sent
directly
to the
Non-ALC
path
with
the course
level adjust circuit. The system
configuration
and
RSS programming
determine whether the inputs are sent to the
ALC
or
Non-ALC
path
with
the course
level adjust circuit.
The
course level adjust
circuit
is
a
microprocessor-controlled gain stage consisting
of analog switches and an
inverting
amplifier.
The gain of this amplifier stage is
determined
by
the
combination of the two logic lines sent from
EEPOT E
on the
TTRC
Audio
board.
The
ALC
circuit consists of two gain adjust
stages.
The maximum gain of the first
stage results in
approximately
13.5
dB.
The
TTRC
Logic
board adjusts the
gain
of
this stage.
The lowest gain
of this stage is -32 dB.
The audio signal
is then routed to an inverting amplifier where it is amplified
by
a
constant
level
of 27 dB. The output (TP5) drives
the tone
processing circuitry and
is
a
source for the
TX
audio fine level adjust circuit.
The
TX
audio level adjust
stage
follows
the
ALC/Non-ALC
transmit source gate.
The transmit
source gate consists of an
inverting amplifier
and
EEPOT
7 (TX
level
adjust). Depending on the setting of
EEPOT
7,
the
gain of this stage can
vary
from
-13
dB
to -2 dB (ALC) or
-11
dB
to
10
dB (course adjust). The nominal audio level
expected at
the
output of
the
level adjust circuit
at
TP6
is
approximately
315
mV
rms.
When
both paths
are
used (Non-ALC/ALC)
in
a
console
priority configured
system,
EEPOT
7
stores
two values. One value
is for the
ALC
path; the other for
the
Non-ALC
path. Therefore,
EEPOT
7
must be adjusted twice, once while
the
ALC
path is active, and once
while
the
Non-ALC
path is active.
1-29