A d v a n c i n g w i r e l e s s t e s t IFR COM-120B Training Program.

a d v a n c i n g w i r e l e s s t e s t

IFR COM-120B Training ProgramIFR COM-120B Training Program

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a d v a n c i n g w i r e l e s s t e s t1st Jan 01

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Course OutlineCourse Outline

Basic Instrument Front Panel Connections Rear Panel Connections Navigation RF Generator Screen Zooming Meter Functions Receiver Screen Duplex Operation Scope Spectrum Analyzer Tracking Generator Applications

Stored Setups Stored Frequency List Memory System Storing and Retrieving Images PCMCIA Card Slot Printing and Capturing EDACS BER Applications Library EasySpan for Windows EasySweep

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COM-120B Basic InstrumentCOM-120B Basic Instrument

250 kHz to 1 GHz Full Featured Service Monitor RF Signal Generator Sensitive 2 uV Receiver Cross Band Duplex High Speed Digitized Spectrum Analyzer High Speed Digitized Scope Generate and Demod FM, AM, PM AC, Battery and Ext. DC operation 38.5 lbs.

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COM-120B Standard FeaturesCOM-120B Standard Features

RF Signal Generator Output Level +13 to -130

0.2 PPM TCXO 2 uV Receiver with 15, 30 and

300 kHz IF filters 50 kHz Scope Full band / Dual Mode

Spectrum Analyzer Digital Voltmeter Audio Level Meter Dual Audio Function

Generators Data Generator DCS, DCS INV DTMF Generator

Encode / Decode DCS, DTMF, CTCSS

RF Frequency Error Meter and Counter

FM Deviation Meter AM Modulation Meter Phase Modulation Meter Audio Frequency Counter RF Power Meter (2 mW - 200 W)

50 W Continuous RF Level Meter Distortion Meter SINAD Meter RS-232

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Options and AccessoriesOptions and Accessories 0.01 PPM OCXO (120B-xTx)

Internal Rechargeable Battery (AC3001)

Tracking Generator (AC3012)

Return Loss Bridge (AC4105)

EasySweep Software (AC1019)

EasySpan for Windows (AC1009W)

Digital / Analog Signaling (AC3011)

CCIR, CCIRH, CCIRH4, EEA, EIA, NATEL, ZVEI, DZVEI, DDZVEI, EURO, 5/6 Tone,

POCSAG RCC Signaling (AC3009)

Tone Remote, IMTS, MTS, 10 PS, 20 PS

Data Generator / BER Meter (AC3007)

MPT-1327 Trunking (AC9161)

Clear Channel LTR Trunking (AC3014)

EDACS Trunking (AC3016)

7.5 kHz IF Filter (AC9162)

SSB Filter (120B-8xx)

Microphone (AC8645)

Antenna (AC1201)

Heavy Duty Ship case (AC8753)

Soft Padded carry case (AC9925)

IEEE-488 Interface (AC3013)

EasyCom Land Mobile test software (AC1022)

Application Library (AC1023)

Nortel Cellular Base Station Software (AC1037)

Programming Manual (AC0301)

Maintenance Manual (AC0600)

Extended Warranty 3/5 year

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RF Input and OutputsRF Input and Outputs

Off the Air M

onitoring

Transmitter connection

Full Duplex TestingHalf Duplex Testing and

Tracking Generator Output

Receiver Transmitter

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Audio Input and OutputsAudio Input and Outputs

Scope / DVM Input

AUDIO / DATA

SINAD IN

EXT MOD IN DEMOD OUT

AUDIO / DATA

GEN OUT

Ext Mod source

for radio under test

Ext Audio Analysis

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Rear PanelRear Panel

RS-232 Serial IO

Direct pin to pin

connection to PC

10 MHz Ext Ref InputOptional GPIB

Interface

Battery

CompartmentExt. DC Input

Master Power Switch

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The Arrow keys are used to position a cursor to an EDIT FIELD.

The TAB Key allows direct access to any field on the screen and is an alternative to incrementing the cursor through other fields.

Function Keys pertain to the Field Selection.

NavigationNavigation

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RF

FL

Level

Output

D= SWEEP LOCKD on/offSET REF

On/Off C-Fwd C-RvsT-Fwd T-Rvs FL

dBm V SINAD=uV mV S=On/Off

T/RAUX GateAUX

T/R Gate

RF Generator (Receiver Testing)RF Generator (Receiver Testing)RF Generator (Receiver Testing)RF Generator (Receiver Testing)

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Stored Frequency ListStored Frequency List

Up to 100 frequency pairs may be stored

Labels allow for easy selection of the correct frequency pair.

SHOW

LIST

Program the Frequency List by pressing the SHOW LIST key on the front panel

Access the stored frequency list by enabling FL on the Frequency field of the Generate or Receive screens

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This area identifies what sources are turned on

GEN1 indicates that FGEN 1 is turned on

GEN1B indicates that FGEN1 is turned on but is in BURST mode

Modulation SourcesModulation SourcesModulation SourcesModulation Sources

The Gen 1 Source field can be configured for a standard 1 kHz tone

The Gen 2 Source field can be configured for a CTCSS Tone

OR

The DATA generator could be used to configure a DCS code for digital squelch systems.

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SINAD Meter FilteringSINAD Meter Filtering

The SINAD meter is commonly configured with a C-MSG filter.

Setting the SPEAKER/PHONES to C-MSG allows the AUDIO/DATA SINAD Input port to be routed to the speaker.

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Placing the cursor on the SCOPE / ANALYZER or METER field allows access to additional controls for that device.

ZoomingZoomingZoomingZooming

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Additional Controls

Bar Graph Meter

Scope or

Analyzer can

be displayed

Meter FunctionsMeter FunctionsMeter FunctionsMeter Functions

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Generate - AF Level MeterGenerate - AF Level Meter

Adjust volume or audio to specific levels prior to Distortion or SINAD measurements.

Measure Vrms Measure dBm (user enters desired

load value) Measure dB relative

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Testing Receiver Audio BWTesting Receiver Audio BW

The Audio BW of the receiver can be measured by setting a reference at 1 kHz then adjust the tone frequency from 300 Hz to 3 kHz while the Audio Level meter is in dB mode.

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Generate - SINAD MeterGenerate - SINAD Meter

Setting the SINAD meter to Average mode with 10 averages will make the readings more stable when manually searching for 12 dB SINAD readings.

Positioning the cursor to the RF Level field allows automatic search for specified SINAD reading.

Note: Averaging should be turned off when performing automatic SINAD search operations.

Scope source can be set to view Internal Modulation source, Audio/Data Input port or Notch Residual to evaluate receiver performance.

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Testing Receiver SensitivityTesting Receiver Sensitivity

RF Signal Generator

Receiver

Under Test

Audio

Filter

R.M.S.

Voltmeter

R.M.S.

Voltmeter

Notch Filter

Audio Output

SINAD =

Signal + Noise + Distortion

Noise + Distortion

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Testing Receiver DistortionTesting Receiver Distortion

After setting the Audio output level to 60% of the rated audio level, the receiver distortion can be measured. Reducing the audio level by 20dB should result in a distortion indication of less than 10%.

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Generate - Spectrum AnalyzerGenerate - Spectrum Analyzer

Modulation Index for a 1 kHz Rate

Rate= Desired Dev (Hz) / Mod Index

3300 Hz Dev / 2.405 = 1372.1 Hz

for Carrier Null (52 dB)

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Questions?Questions?

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RF

FL

INPUT

Atten

Demod

IF BW

D= SWEEP LOCKD on/off SCAN

T/R ANT

30 0

On/Off C-Fwd C-RvsT-Fwd T-Rvs FL

FM AM PM

300 kHz 15 kHz 30 kHz

Receiver (Transmitter Testing)Receiver (Transmitter Testing)Receiver (Transmitter Testing)Receiver (Transmitter Testing)

BW required to demodulate signal

26 dBCFIF BW

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AFGEN OutAFGEN Out

The internal function generators can be used to externally modulate the transmitter.

Two variable rate function generators, DTMF, DCS, Ext Mod source and Microphone sources are available.

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Careful attention to filter settings must be maintained to avoid measurement errors.

Post Detection FiltersPost Detection FiltersPost Detection FiltersPost Detection Filters

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Tone DecodingTone Decoding

Care must be taken to ensure that the Filter for the Audio Counter is set correctly prior to decoding.

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RF Frequency Error MeterRF Frequency Error Meter

Frequency tuning can be easily done by setting the Range to a fixed range.

Set the Gate time to 0.1 S to take fast readings

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Audio Frequency CounterAudio Frequency Counter

The Audio counter offers more resolution when zoomed.

For rates less than 300 Hz, 0.1 Hz resolution can be obtained with a 1 S gate time.

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RF Power MeterRF Power Meter

The dBm scale provides a convenient way to measure cable loss by using a reference cable.

A 0.4 dB cable loss can cause 10% error in Power measurement. If not accounted for.

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RF Level MeterRF Level Meter

Measures the signal strength an off the air signal through the Antenna port.

The level may vary with different IF bandwidth selections.

For maximum accuracy, perform the SET LVL calibration procedure.

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Deviation MeterDeviation Meter

Transmitter Maximum deviation is the greater of the two values

Deviation Symmetry = Deviation (higher) - Deviation (lower)Deviation (higher)

X 100

1.11 - 1.10

1.11

= 0.9%

The Deviation meter must be zeroed when DC coupled.

When AC coupled, zeroing is not required.

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Duplex OperationDuplex Operation

Simultaneously Generate and Receive operation for Full Duplex Any Offset between Generate and Receive frequencies in 2.5 kHz steps

Move the cursor to these fields to expand the screen to access all of the Receiver or Generator functions.

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OscilloscopeOscilloscope

Trigger Modes:NORMALAUTOMATIC1 SHOT

Display Modes:LIVE AVGRECALL MIN HOLDCOMPARE PK HOLDLIVE-REF STOREREF-LIVE

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Scope Input SelectionsScope Input Selections

EXTERNAL INPUTS:SCOPE/DVM - GNDSCOPE/DVM - ACSCOPE/DVM - DC

INTERNAL INPUTS:Detector Out Data DecoderAudio/Data Gen Out RF PowerNotch Residual Demod Out Conn.AF Cntr Mod MetersDTMF/SINAD

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Peak Hold FeaturePeak Hold Feature

The scope PK and MIN Hold feature allows monitoring of maximum and minimum modulation variations.

Monitor FM or AM Broadcast Monitor Transmitter Deviation

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Independent control of Sweep Rate and RBW Reference Level Offset adjustment Offset Tracking Generator Signal Find feature Split Screen / Dual mode operation Zero - Full Span display modes in 1,2,5 sequence

Spectrum AnalyzerSpectrum Analyzer

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Track Gen

ON/OFF

DEFAULT

LOCK

CONFIG

Center Freq

Offset

ModeAVG RECALLPK Hold COMPAREMIN Hold LIVE-REFSTORE REF-LIVELIVE

Span Sweep RBW COUPLE DFLT

Frequency SET REF FIND FIND LVL CONFIG Sweep Width Split

MarkerREFScaleUnits

Spectrum AnalyzerSpectrum Analyzer

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Peak and Min HoldPeak and Min Hold

Like the scope, the Spectrum Analyzer supports a Peak and Min hold feature.

Verify signal amplitude does not vary

Verify that a channel does not go off the air.

Verify presence of spuratic interference signals.

Identify the frequency of pulsed or short duration signals.

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The problem:

How to ensure that RX and TX antennas are sited

correctly to maximize isolation and thereby

prevent RX desensitization?

Solution:

Tracking generator swept across TX band with

RX antenna connected to analyzer input.

Using the Tracking Generator for Antenna Using the Tracking Generator for Antenna IsolationIsolation

TX outRX in

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Return LossBridge

SignalGenerator

SpectrumAnalyzer

Source

Reflected

DUT Port

Return Loss is the difference betweena measured reference signal, and themeasured DUT .

It can be used to check the degree ofmismatch of filters, antenna’s,receiver inputs, amplifier inputs andisolators. CAUTION: Measurements cannot be made beyond

the directivity (resolution) of the bridge itself.

The Return Loss Bridge (AC4105)The Return Loss Bridge (AC4105)

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VSWR Bridge Out

(DUT)

Source

Reflected

Antenna Measurements using a Return Loss Antenna Measurements using a Return Loss Bridge (AC4105)Bridge (AC4105)

Antenna VSWR / Return Loss Measurement

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Conversion ChartsConversion Charts

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Using the Tracking Generator for Cable FaultUsing the Tracking Generator for Cable Fault

This image shows a series of nulls due to an open at the end of a cable

Specialized software allows calculation of distance

Cable under test

Tee connector on TrackingGenerator (AUX) Output

Antenna Input

EasySpan for Windows

492 * Vel. Factor

Delta Freq. in MHzDistance ft.=

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Using the Tracking Generator for Filter TuningUsing the Tracking Generator for Filter Tuning

This image indicates the characteristics of a filter

Notch depth of 86.78 dB Frequency tuned to 461.8358 MHz 3 dB Bandwidth of 198.4 kHz

Measurements Notch Depth Bandwidth Insertion Loss at Passband

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Duplexer TuningDuplexer Tuning

Split screen mode makes Duplexer tuning easy.

Set a 0 dBm reference with cables.

Switch between 0 and 30 dB input attenuation to tune for insertion loss or notch depth.

Simultaneously view wide and narrow windows

Additional range can be obtained by reducing the Resolution Bandwidth and slowing the sweep speed.

a d v a n c i n g w i r e l e s s t e s t

Store and RecallStore and Recall

Up to 50 Storage Locations are available. Storage Locations are labeled 0 - 49. Screen settings that are saved are:

Generator, Receiver, Duplex Generator

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Stored SetupsStored Setups

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2.5 MB Internal File System2.5 MB Internal File System

Formatting of the File System is similar to a standard DOS file System.

Access the File system through the SHOW LIST key.

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Stored Screen imagesStored Screen images

Screens can be saved as PCX or BMP formats

Saved screens (PCX or BMP) can be stored to the internal Flash File System

Saved screens (PCX or BMP) format can be stored to the external PCMCIA card

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Stored Screen images Stored Screen images

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Storing Screen ImagesStoring Screen Images

Setup Key

11 Print Screen Setup

Screen Images may be stored into the internal 2.5 MB file system by pressing the HOLD SCRN key and Printing to the file system

Setting the filename to *.* will create filenames automatically beginning with 00000001.pcx

Setting the filename to test*.* will create filenames automatically beginning with test0001.pcx

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Retrieving Screen ImagesRetrieving Screen Images

Screen Images may be extracted from the COM-120B internal File system with a standard terminal program using XMODEM and a pin-to-pin RS-232 connection.

Setup the COM-120B RS-232 Host, 9600, 8 Data Bits 1, Stop Bit, Parity None, CTS/RTS Handshake, RCI Echo OFF, RCI Control ON

Setup Hyperterminal for Direct connection Mode Direct Baud 9600, 8 Data Bits, 1 Stop Bit, Parity None, Hardware Handshake

In Hyperterminal type the following command mmem:down:xmode “filename.pcx”

filename.pcx would be substituted with a valid filename that appears in the COM-120B file directory.

In Hyperterminal select File Transfer via XModem

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File Download ExampleFile Download Example

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PCMCIA Card SlotPCMCIA Card Slot

Standard Computer PC Type 1 or type 2 card interface.

Will accept either Flash or Static RAM Memory Cards.

Can be configured to use Hays Compatible PCMCIA Modem or a Serial card. Use to connect to a remote computer running EasySpan for Windows.

Can be used to Load the Test Set Operating System or transfer screen images to a PC.

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Executing the EDACS OptionExecuting the EDACS Option

The EDACS option is accessed by pressing the “SPCL” key and selecting Item 4 for EDACS Trunking

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EDACS OptionEDACS Option

Auto-test Radio or Repeater

Repeater Simulator Manual test for Radio

Radio Simulator Manual test for Repeater

Setup Screen Required for both Manual and Automatic tests

Configure system parameters Configure Frequency list

Store and Label Setups

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Setup - System ConfigurationSetup - System Configuration

Information in this screen is used by all other EDACS test modes and must be configured correctly for proper operation

Note: (System Band Selection)Narrow (900 MHz) - 4800 baud - 12.5 kHz ch bwWide (400 / 800 MHz) - 9600 baud - 25 kHz ch bw

The Control and Working Channel numbers must be different

Required Information1. TX / RX frequencies of at least two channels2. The Site ID number3. The System Data Rate

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Entering the frequency listEntering the frequency list

The channel frequencies are set to the Standard FCC frequency list by default pressing either the 800 or 900 MHz keys

User defined frequencies may be entered by selecting USER

If USER is selected, the operator may enter any frequency that he wishes for both the Mobile RX and the Mobile TX

Only Two channel frequencies are required to enable radio testing

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Test setup for Radio TestTest setup for Radio Test

Connect Transmitter Output to COM-120B TR Type N jack

Connect Radio Receive Audio Output to the COM-120B Audio / Data SINAD Input

Connect COM-120B Audio / Data GEN OUT to Radio TX Audio

PTT RX Audio

TX Audio

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Manual Test for RadioManual Test for Radio

To test a radio, select the Repeater Simulator

Enter the Working Channel number Select the input port to TR Select the 30 kHz IF filter Set Output level to -40 dBm Set Output port to TR Adjust the COM-120B’s receiver

Squelch control until the audio is squelched off

Key the Radio The Group ID, Logical ID and Call Type

will be decoded

System messages appear here

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Manual Radio Tests (Radio initiated call)Manual Radio Tests (Radio initiated call)

With the Transmitter keyed, the following measurements can be made Power Frequency Deviation

Voice Low Speed Data

AF Frequency Distortion

Note:

Positioning the cursor to the Deviation field allows filter selections for DATA (300 Hz Low Pass) or Voice (300 Hz High Pass).

Selecting DATA will allow measurement of Low Speed Data.

Selecting Voice will filter out the Low Speed Data.

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Manual Tests (Radio Initiated Call)Manual Tests (Radio Initiated Call)

High Speed Data Deviation can be measured with the Extended Measurement Scope mode

Configure the scope as shown

Key the Transmitter and press the HOLD SCRN button when the waveform appears

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High Speed Data CaptureHigh Speed Data Capture

High Speed data burst should be approximately 3 kHz Deviation

Low Speed Data should be approximately 750 Hz Deviation

The DETECT selection for Scope Coupling allows the data to be unfiltered

On the first data burst the radio transmits ID information on the Control Channel and requests a working channel.

The second data burst is transmitted on the working channel approximately 200 ms later.

CC WC

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Manual Tests (Repeater Initiated Call)Manual Tests (Repeater Initiated Call)

Configure Function Generator 1 for a 1000 Hz tone with 3 kHz deviation.

Move the Cursor to the Call Type field and press the CALL function key.

The radio squelch should open and a 1 kHz tone should be heard.

Note:

To enable a 1 kHz tone, position the cursor to the Mod Source field and select “FM”

The Deviation and frequency can then be entered

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After placing a call, the demodulated audio can be analyzed with a Distortion, SINAD or Audio Level meter.

The COM-120B RF Output level can be adjusted to find the 12 dB SINAD sensitivity of the radio’s receiver.

Manual Tests (Repeater Initiated Call)Manual Tests (Repeater Initiated Call)

Note:The COM-120B cannot receive or decode the transmitter if the Distortion, SINAD or AF Level meter are turned on.

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Store setupsStore setups

Now would be a good time to save the setups

Select the STORE key

A label name and location can be entered

The setups and frequency list that have been entered will be stored under this label name after pressing the SAVE key.

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The COM-120B can test the radio automatically

The Registration test requires that the radio be configured for automatic login registration

The Radio Test requires only an RF connection from the Transmitter Output to the COM-120B TR connector

Automatic Test FeatureAutomatic Test Feature

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Automatic Test FeatureAutomatic Test Feature

The Audio test requires audio connections to the Audio/Data GEN Out and the Audio/ Data SINAD IN connectors

Any test feature may be Enabled or Disabled as required

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Printing / Capturing Test ResultsPrinting / Capturing Test Results

Print Directly to an RS-232 Printer

Print to a Standard Terminal Program Allows storage of test results

Note:

Set RS-232 parameters from the system Setupscreen prior to entering the EDACS Option

Automatic test results may be captured and savedusing a terminal program

RS-232 cable connection to a PC is a directpin-to-pin connection

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BER MeterBER Meter

Data Rates (BPS)

75, 150, 300, 600, 1200, 2400, 4800, 9600

RF or Base band operation is supported

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EasySpan for WindowsEasySpan for Windows

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Applications LibraryApplications Library

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EasySweepEasySweep

This memory resident application leads the operator and controls the COM-120B to make many standard measurements automatically.

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Common Operator ProblemsCommon Operator Problems

Unit will not Decode tone formats Improper filter settings for the AF Counter The Squelch is not set correctly

The Analyzer display does not look correct The COUPLE function needs to be selected for the SCAN width selected The SET REF function was activated with a signal connected

Nothing shows up when I turn on the Tracking Generator An offset has been entered into the Tracking Generator

The RF Signal Generator has no output Output port is set to TR Gate or AUX Gate

The Function generator is turned on but has no output The Function generator is set to Burst mode

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Common Operator ProblemsCommon Operator Problems The Power meter reading is not correct

The Frequency is not entered The cable loss was not compensated for The cable loss was compensated as negative value instead of

positive The SINAD meter is too unstable to use

Averaging has not been turned on The Deviation meter is not accurate

They have not taken residual FM into account The Scope Demod is not centered

The Deviation meter is DC coupled and needs to have an FMZ operation performed

The Scope vertical position needs to be adjust with the receiver squelched off

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A d v a n c i n g w i r e l e s s t e s t IFR COM-120B Training Program.

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