Motorola MSF 5000 Instruction Manual page 73

MSF
5000
Instruction Manual
Chapter
1
Description
TTRC
Audio Board
SIMULCAST
MOD
AUDIO
TKG
AUDIO
MUTE
REV BURST
DEVIATION
AUDIO
LEVEL ADJUST
GATE
AUDIO
GATE
EEPOT
B
REVERSE
BURST
GENERATOR
CIRCUITRY
VB
GEN
TX
DATA
MSFI062
022294JNM
Figure 1-16
Simulcast Modulation Audio Circuitry
Differential Amplifier
Simulcast modulation audio
enters the
TTRC
Logic
board connector J2900 and is
passed to the
TTRC
Audio
board at connector J2904 as GEN
TX DATA
(+
/-)
(600 Q
load). GEN
TX DATA
(+
/-) is then superimposed on
VB
by
a
differential amplifier.
Audio
or data
leaving
the
differential amplifier is directed down two paths,
one
of
which
is selected
by
an audio gate. Path
1 goes directly
to the audio gate; path
2
goes through
a
reverse burst generator circuit.
Signals leaving
the
audio gate
are
sent to the data deviation adjust
stage.
Reverse Burst Generator
Reverse burst is phase shifting of the
PL
tone
signal upon termination of
a
line
PTT
in
a
PL
distribution simulcast
station.
The reverse burst generator consists of
a
differential amplifier and associated circuitry.
Data Deviation
Adjust Stage
Audio
leaving
the
simulcast audio gate is routed to the same
deviation level
adjust stage described in
the
trunking modulation audio
section.
The level adjust
stage consists of an
inverting amplifier
and
EEPOT
b
(trunking
data
level).
Audio
leaving
the
inverting amplifier
is sent
to
trunking
data level audio gate.
This
gate
acts as
a
switch between simulcast modulation audio and VB. Simulcast
modulation audio only
passes through
the gate
if TKG AUDIO MUTE
is in
a
logic
low
state.
68P81092E02
3/10/94
1-35
MSF
5000
Instruction Manual
Chapter
1
Description
TTRC
Audio Board
SIMULCAST
MOD
AUDIO
TKG
AUDIO
MUTE
REV BURST
DEVIATION
AUDIO
LEVEL ADJUST
GATE
AUDIO
GATE
EEPOT
B
REVERSE
BURST
GENERATOR
CIRCUITRY
VB
GEN
TX
DATA
MSFI062
022294JNM
Figure 1-16
Simulcast Modulation Audio Circuitry
Differential Amplifier
Simulcast modulation audio
enters the
TTRC
Logic
board connector J2900 and is
passed to the
TTRC
Audio
board at connector J2904 as GEN
TX DATA
(+
/-)
(600 Q
load). GEN
TX DATA
(+
/-) is then superimposed on
VB
by
a
differential amplifier.
Audio
or data
leaving
the
differential amplifier is directed down two paths,
one
of
which
is selected
by
an audio gate. Path
1 goes directly
to the audio gate; path
2
goes through
a
reverse burst generator circuit.
Signals leaving
the
audio gate
are
sent to the data deviation adjust
stage.
Reverse Burst Generator
Reverse burst is phase shifting of the
PL
tone
signal upon termination of
a
line
PTT
in
a
PL
distribution simulcast
station.
The reverse burst generator consists of
a
differential amplifier and associated circuitry.
Data Deviation
Adjust Stage
Audio
leaving
the
simulcast audio gate is routed to the same
deviation level
adjust stage described in
the
trunking modulation audio
section.
The level adjust
stage consists of an
inverting amplifier
and
EEPOT
b
(trunking
data
level).
Audio
leaving
the
inverting amplifier
is sent
to
trunking
data level audio gate.
This
gate
acts as
a
switch between simulcast modulation audio and VB. Simulcast
modulation audio only
passes through
the gate
if TKG AUDIO MUTE
is in
a
logic
low
state.
68P81092E02
3/10/94
1-35