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3.8.4 MIC
CONNECTOR
A 4·pin
connector is
provided with microphone
bias
and
PTT
capability.
De
pressing the PTT
button o
n
the
micro-
phone is the
same
as
changing
the
FUNCTION
switch
.
Function
With
PIT
Function With
PTI
Open
D
e prcs
ed
HlGEN
HI
GEN
GEN
GEN
PWR
MON
GEN
SENS MON
H
I
GEN
The mic
input
conta
ins
a deviation
limiter
to
limit
voice
modulation
peaks
as
in
a mobile radio.
3.8.5
EXT
LEVEL
Control of
the
microphone
and
o the
r
external
signal
generators
modulation level is
provide
d. When in the
full
counte
r
clockwise
position
,
the
source is
disabled.
Mod-
ulation
levels
are viewed
by
selecting
the "
DEV/%AM"
display on the left
LC
D
and can
a lso
be viewed
on
the
modulation scope.
3.8.6
CODE-SYNTHESIZER
LEVEL
The
pote ntio meter controls
the internal
code synthesizer
modulation level.
Whe
n
in
the
full
counterclockwise
positio
n,
a
minimum
modula
tion level
is
reached.
ON/
OFF
control
is
provided by the modulation switch.
Mod-
ulation
levels
are
viewed by
selecting
the
''DEV/%
AM''
display
on
the left
LCD
and
can
be
viewed on
the
mod-
ulation scope
. Also
the code
synthesizer operates
inde-
pendently
of
the function switch setting.
3.8.7 MODULATION SWITCH
A
3
position toggle switch controls the
code synthesizer
modulation
source.
I. Cont.- Allows
continuo us
modulatio
n
(recycle)
sig-
nal
outputs.
Sequential
tone
patterns
will
be repeated
as
long
as
this
switch
is enabled.
2. OFF-Turns
off the
modulation signal.
If in
the
DPL
or
lDPL
mode,
returning
the
switch
to the OFF from
continuous
or
burst
produces
a
134.4 Hz
stop
tone
burst for 120 ms.
3. Burst-For
PL,
tone A
and
tone
B
modes
the
output
is present for as long as the switch
is he
ld
in the burst
position
.
For
A/
B
Var,
A/B
T&V,
and tone
remote,
putting the switch
in the
Burst
position causes one
cycle to be output. For tone
remote,
the
last
A tone
is
output
for
as
long
as
the
switch
is held in the burst
position to
sim ulate
low guard
tone.
In
the
DPL
o
r
IDPL
modulation
mode the burst
position
causes
continuous
cycling
of the
code
as
long
as
the switch
is
depressed. When the switch is released
the code completes the cycle
it
was
in
and a 120
ms
burst of stop
tone
(134.4
Hz)
is
gene
rated.
3.8.8 CODE SYNTHESIZER MODE SELECTION
The
code
synthesizer
provides capabi lity to select
any
of
the
fo rmats listed
below. Each
of
10
positio ns has a
corresponding
LED to
indicate
which mode
is
selected
.
Only
whe
n
the modulatio
n switch
is toggled away from
the
off
position
will
the
o utputs
be generated and dis-
played
in
the right
LCD.
The
modula tio
n switch must
be
active for
se tting
deviation with the
code synthesizer
level
control. Pos
itionin
g of
the
selecte
d
mode is
performed
by
the
lb.J
vertical
display
cursor.
As
with
all cursor
controls
in
the
unit
,
an
audible
feedback tone
will
verify
acceptance
of a
switch
activation
.
1.
PL
C
OUNT
-Code synt
h
es
izer
o utputs
pro-
grammed
PR
IVATE
LINE
freq uency. displays
counted
freque ncy of
incoming
PL
tones if
in
either
mo nito
r
functio
n.
2.
PL-Progra
mmed PRIVATE LINE
frequencies to
I
kHz.
3.
DPL-
Programmed D
IGITAL
PRIVATE
LINE
codes
are o utput.
MODULAMN
CDdl! Synlh
lvl
tKiillvl
Mooi
01Jt
t.~I
Mod
In
FIGURE
3.7-CLOSEUP OF MODULATION
SECTION
3-10
-
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