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2.11.0 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 allows 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" for 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.
2.13.0 MULTIPURPOSE OSCILLOSCOPE
This general purpose scope is ideal for waveform analysis
in two-way communication servicing. Use it for viewing
modulation signals (either internally or externally gener-
ated). detection of asymmetric modulation or audio dis-
tortion. and general purpose signal 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-remote 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), as well as a signal applied to the external BNC
input. Separate controls are provided for independently
setting the levels of the I KHz tone, the code synthesizer,
and the external modulation sourc~s. The I KHz test
tone is a convenient source of modulation for making
SIN AD measurements. A "MOD OUT" connector pro-
vides external access to all of the modulation signals.
2.16.0 DIGITAL/ANALOG VOLTMETER
The built-in voltmeter provides circuit and power supply
service capability. AC voltage reading are RMS values.
2-2
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 I, .1, and .01 MHz/div 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 10 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 In/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.
2.18.0 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-2200 (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
DTMF, a real time encoder, is one selection possible. There
are also encoding formats available for operator selection
which include: 1) I6 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 I6 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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