Digital/Analogvoltmeter; Spectrumanalyzer; Two-Wayserviceoption; Off-The-Airmonitor - Motorola R-2400 Operator's Manual

2.II.O
OFF.THE-AIR MONITOR
The
1.5 microvolt sensitivity of
the
Communications
Service
Monitor receiver allows off-the-air monitoring
and
measurement
of
transmitter frequency error
and
deviation to
1000
MHz. A
variable
squelch attows weak
signals to
be
monitored, but
can be set tighter to
ensure
the proper signal-to-noise ratio
for
measurement accura-
cy. The off-the-air monitor function
enables frequent
parameter
checks
without leaving
the shop, thus spotting
system degradation
early and keeping
service
costs
down. Bandwidth
can
be set "'WIDE" Tor off-channel
signal location or
wide band FM; or "NARROW'''
for
maximum sensitivity and selectivity.
2.12.0 OFF-THE-AIR PRIVATE
LINE
FREQUENCY
COUNTER
Identifies the PL frequency
of
any radio under test to
allow complete testing
of PL subaudible tone signalling.
2.I3.0
MULTIPURPOSE OSCILLOSCOPE
This general purpose
scope
is
ideal for waveform
analysis
in two-way communication servicing. Use it for viewing
modulation
signals
(either internallyor
externally
gener-
ated), detection
of asymmetric modulation or audio
dis-
tortion, and
general purpose signar tracing and trou-
bleshooting.
2.14.0 MULTIMODE CODE SYNTHESIZER
The Communications
Service
Monitor
generates
pRI-
VATE LINE
tones
(PL), DIGITAL PRIVATE LINE
codes
(DPL),
two-tone sequential paging
codes
and
tone-rernote signalling tones. All
codes
are available
at
the
"MOD OUT" jack,
as
well
as
being
used
internally to
modulate the RF signal generator. This eliminates
the
necessity of
using separate generators
and
oscillators
for
general
servicing, setting transmitter deviation, or
for
checking tone remote
base
control
lines.
2.15.0 SIMULTANEOUS MODULATION
Modulation is simultaneously available from an internal
I
KHz tone generator,
a
multimode code synthesizer,
and
from external inputs. The external modulation
can
be
voice from
a standard Motorola mobile radio micro-
phone
(which plugs into the front
panel
of
the instru-
ment),
os
well
as a
signal applied to the external BNC
input.
Separate
controls
are
provided for independently
setting the levels
of the
1
KHz tone,
tlr.
code synthesizer,
and the external modulation sourcis. The i
KHz
test
tone is a convenient source of
modulation
for
making
SINAD
measurements.
A "MOD OUT"
connector pro-
vides external
access
to all of the modulation
signais.
2.16.0 DIGITAL/ANALOG VOLTMETER
The built-in voltmeter provides circuit
and
power supply
service
capability. AC voltage reading are RMS valGs.
2.17.0
SPECTRUM ANALYZER
The
R-2400 includes
a
spectrum analyzer which pro-
vides frequency spectrum display while allowing
the
user
to monitor
the audio of
the
programmed frequency
signal. Three
dispersions
of
l,
.1, and .01 MHz/Oiu
are
available.
In
"Anlzr
Sens
Mon", the ',Antenna" port
is
used. The
range
of power
levels displayed when the
step
attenuator is
in
the
0 dB
position
is
-40
dBm (top
graticule) to
-100 dBm (noise floor).
Vertical divisions
are
l0
dB
each. When
70 dB attenuation is
added using
the
step
attenuator, the
range
of power
levels displayed
becomes
+ 27 dBm
to -30 dBm.
Care must
be taken to
not
exceed
the maximum input level
of
.5 watt
(+27
dBm) at the Antenna input.
In "Anlzr pwr Mon",
the
RF signal that is applied to
the
"RF rn/out" port
is
sampled
and displayed. The required amount
of
at-
tenuation
to
maintain an
on-screen display can be
ad-
justed with the
step attenuator.
2.IE.O THE
FIRST
IN A
SERIES/TWO.WAY
SERVICE OPTION
The
Two-wAY
SERVICE
oPTIoN
is the first
in
a
series
of
new option cards. This
pC
board, plug in
compatible
with any
R-22a0
(or
R-2400) via an
open
option
module
slot and
comes equipped
with
the
following
functions:
TWO-WAY SERVICE OPTION
DPL
DECODE
DTMF ENCODE
DTMF
DECODE
Some
of
the major
features
of
the
DpL
Decoder in-
cludes OFF-THE-AIR decoding
of
DpL
or
IDPL
codes. The Two-way
Service
option will
decode
only
valid DPL
codes
and
will not
display invalid
codes.
with
the DPL
encoder, standard
in
every R-2200 (or
R-2400), the
service technician has a
,,failsafe
opera-
tion"
making
it
easier
and
less
time
consuming
when
performing a complete
DPL
system check.
The option
card also provides
multiple
methods in which
to
encode DTMF
tones. The
most basic form of generating
DTMR
a
real time
encoder, is one selection possible.
Therc
are also encoding formats available
for
operator selection
which include:
1)
l6 digit
storage
(BATCH
ENCODE) ,2)
user programmable timing,
and
3)
simultaneous
pL
and
DTMF
encode.
A
last function of
the
Two-Way Option
is
DTMF
Decode.
In this
mode the service
monitor
will
decode
DTMF
tones
OFF-THE-AIR or via
the modulation input BNC
connec-
tor. This option
will
decode and
store up
to
16
DTMF
digits.
with
DPL, DTMF
and the standard
pL
Encode
and
Decode
built-in, the
R-2210 and R-2410 Communica-
tions
Service
Monitors qualify
as a complete signalling
simulator,
capable
of
performing a complete signalling
system check on the land mobile industries most com-
mon signalling
formats.
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