Transcript IFR COM-120B Training Program

IFR COM-120B Training Program
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1st Jan 01
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Course Outline
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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
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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 Instrument
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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 Features
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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
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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 Accessories
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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)
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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 Outputs
Half Duplex Testing and
Tracking Generator Output
Receiver
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Transmitter connection
Full Duplex Testing
Transmitter
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Audio Input and Outputs
Scope / DVM Input
AUDIO / DATA
SINAD IN
EXT MOD IN
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AUDIO / DATA
GEN OUT
DEMOD OUT
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Ext Mod source
for radio under test
Ext Audio Analysis
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Rear Panel
Master Power Switch
Battery
Compartment
Ext. DC Input
10 MHz Ext Ref Input
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Optional GPIB
Interface
RS-232 Serial IO
Direct pin to pin
connection to PC
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Navigation
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.
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RF Generator (Receiver Testing)
RF
D=
D on/off
SET
REF
T-Fwd
T-Rvs
C-Fwd
uV
mV
V
AUX
T/R
Gate
AUX
Gate
SWEEP LOCK
FL
On/Off
C-Rvs
FL
Level
dBm
Output
T/R
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SINAD= S=On/
Off
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Stored Frequency List
Up to 100 frequency pairs may be stored
Labels allow for easy
selection of the correct
frequency pair.
Program the Frequency
List by pressing the
SHOW LIST key on the
front panel
SHOW
LIST
Access the stored frequency list
by enabling FL on the Frequency
field of the Generate or Receive
screens
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Modulation Sources
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
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.
The Gen 1 Source
field can be
configured for a
standard 1 kHz tone
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SINAD 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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Zooming
Placing the cursor on the SCOPE / ANALYZER or METER field allows access to
additional controls for that device.
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Meter Functions
Scope or
Analyzer can
be displayed
Additional Controls
Bar Graph Meter
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Generate - AF Level Meter
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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 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 Meter
Positioning the cursor to the
RF Level field allows
automatic search for
specified SINAD reading.
Setting the SINAD meter to
Average mode with 10
averages will make the
readings more stable when
manually searching for 12 dB
SINAD readings.
Note: Averaging should be turned off when
performing automatic SINAD search
operations.
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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 Sensitivity
RF Signal
Generator
Receiver
Under Test
Audio Output
Audio
Filter
R.M.S.
Voltmeter
Notch Filter
R.M.S.
Voltmeter
SINAD =
Signal + Noise + Distortion
Noise + Distortion
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Testing 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 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?
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Receiver (Transmitter Testing)
RF
D=
D on/off SCAN SWEEP LOCK
FL
On/Off
T-Fwd
T-Rvs
INPUT
T/R
ANT
Atten
IF BW
30
CF
0
26 dB
Demod
FM
BW required
to demodulate
signal
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AM
PM
IF BW
300 kHz 15 kHz
30 kHz
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C-Fwd
C-Rvs
FL
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AFGEN 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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Post Detection Filters
Careful attention to filter settings must be
maintained to avoid measurement errors.
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Tone 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 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 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 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 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 Meter
The Deviation meter must be
zeroed when DC coupled.
When AC coupled, zeroing is
not required.
Transmitter Maximum deviation is the greater of the two values
1.11
1.10
Deviation Symmetry = Deviation (higher) - Deviation (lower)
Deviation (higher)
1.11
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X 100 = 0.9%
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Duplex Operation
Move the cursor to these
fields to expand the
screen to access all of
the Receiver or
Generator functions.
 Simultaneously Generate and Receive operation for Full Duplex
 Any Offset between Generate and Receive frequencies in 2.5 kHz steps
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Questions?
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Oscilloscope
Display Modes:
LIVE
AVG
RECALL
MIN
HOLD
COMPARE
PK HOLD
LIVE-REF
STORE
REF-LIVE
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Trigger Modes:
NORMAL
AUTOMATIC
1 SHOT
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Scope Input Selections
INTERNAL INPUTS:
Detector Out
Audio/Data Gen Out
Notch Residual
AF Cntr
DTMF/SINAD
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Data Decoder
RF Power
Demod Out Conn.
Mod Meters
EXTERNAL INPUTS:
SCOPE/DVM - GND
SCOPE/DVM - AC
SCOPE/DVM - DC
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Peak Hold Feature
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The scope PK and MIN Hold
feature allows monitoring of
maximum and minimum
modulation variations.
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Monitor FM or AM Broadcast
 Monitor Transmitter Deviation
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Spectrum Analyzer
 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
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Spectrum Analyzer
Span
Sweep
RBW
COUPLE
DFLT
Frequency
SET REF
FIND
FIND LVL
CONFIG
Sweep Width
Split
Track Gen
ON/OFF
DEFAULT
LOCK
CONFIG
Center Freq
Offset
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Mode
AVG
RECALL
PK Hold
COMPARE
MIN Hold LIVE-REF
STORE
REF-LIVE
LIVE
Marker
REF
Scale
Units
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Peak and Min Hold
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Like the scope, the Spectrum
Analyzer supports a Peak and
Min hold feature.
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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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Using the Tracking Generator for Antenna
Isolation
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.
RX in
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TX out
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The Return Loss Bridge (AC4105)
Return Loss
Bridge
DUT Port
Signal
Generator
Source
Return Loss is the difference between
a measured reference signal, and the
measured DUT .
Reflected
Spectrum
Analyzer
It can be used to check the degree of
mismatch of filters, antenna’s,
receiver inputs, amplifier inputs and
isolators.
CAUTION: Measurements cannot be made beyond
the directivity (resolution) of the bridge itself.
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Antenna Measurements using a Return Loss
Bridge (AC4105)
Antenna VSWR / Return Loss Measurement
Reflected
Source
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VSWR
Bridge
Out
(DUT)
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Conversion Charts
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Using the Tracking Generator for Cable Fault
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This image shows a series of nulls
due to an open at the end of a cable
EasySpan for Windows
 Specialized software allows
calculation of distance
Antenna Input
Tee connector on Tracking
Generator (AUX) Output
Distance ft.=
Cable under test
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492 * Vel. Factor
Delta Freq. in MHz
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Using the Tracking Generator for Filter Tuning
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This image indicates the characteristics
of a filter
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Notch depth of 86.78 dB
 Frequency tuned to 461.8358 MHz
 3 dB Bandwidth of 198.4 kHz
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Measurements
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Notch Depth
 Bandwidth
 Insertion Loss at Passband
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Duplexer Tuning
 Split screen mode
Simultaneously view wide and narrow windows
Additional range can be obtained by reducing
the Resolution Bandwidth and slowing the
sweep speed.
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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.
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Store 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 Setups
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2.5 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 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
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Storing 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 Images
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Screen Images may be extracted from the COM-120B internal File
system with a standard terminal program using XMODEM and a pinto-pin RS-232 connection.
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Setup the COM-120B RS-232
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Setup Hyperterminal for Direct connection
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Mode Direct
Baud 9600, 8 Data Bits, 1 Stop Bit, Parity None, Hardware Handshake
In Hyperterminal type the following command
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Host, 9600, 8 Data Bits 1, Stop Bit, Parity None, CTS/RTS Handshake, RCI Echo OFF, RCI Control
ON
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 Example
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PCMCIA Card Slot
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Standard Computer PC Type 1 or type 2 card interface.
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Will accept either Flash or Static RAM Memory Cards.
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Can be configured to use Hays Compatible PCMCIA Modem or a Serial
card. Use to connect to a remote computer running EasySpan for
Windows.
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Can be used to Load the Test Set Operating System or transfer screen
images to a PC.
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Executing the EDACS Option
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The EDACS option is accessed by
pressing the “SPCL” key and selecting
Item 4 for EDACS Trunking
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EDACS Option
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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 Configuration
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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 bw
Wide (400 / 800 MHz) - 9600 baud - 25 kHz ch bw
The Control and Working Channel numbers must be
different
Required Information
1. TX / RX frequencies of at least two channels
2. The Site ID number
3. The System Data Rate
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Entering the frequency list
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The channel frequencies are set
to the Standard FCC frequency
list by default pressing either the
800 or 900 MHz keys
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User defined frequencies may be
entered by selecting USER
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If USER is selected, the operator
may enter any frequency that he
wishes for both the Mobile RX and
the Mobile TX
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Only Two channel frequencies are
required to enable radio testing
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Test setup for Radio Test
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Connect Transmitter Output to COM120B TR Type N jack
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Connect Radio Receive Audio Output
to the COM-120B Audio / Data SINAD
Input
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Connect COM-120B Audio / Data GEN
OUT to Radio TX Audio
TX Audio
PTT
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Manual Test for Radio
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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)
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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)
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High Speed Data Deviation can be
measured with the Extended
Measurement Scope mode
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Configure the scope as shown
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Key the Transmitter and press the
HOLD SCRN button when the
waveform appears
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High Speed Data Capture
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High Speed data burst should be
approximately 3 kHz Deviation
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Low Speed Data should be
approximately 750 Hz Deviation
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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.
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Manual Tests (Repeater Initiated Call)
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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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Manual Tests (Repeater Initiated Call)
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After placing a call, the
demodulated audio can be
analyzed with a Distortion, SINAD
or Audio Level meter.
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The COM-120B RF Output level
can be adjusted to find the 12 dB
SINAD sensitivity of the radio’s
receiver.
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 setups
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Now would be a good time to save
the setups
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Select the STORE key
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A label name and location can be
entered
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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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Automatic Test Feature
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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
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Automatic Test Feature
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The Audio test requires audio
connections to the Audio/Data GEN Out
and the Audio/ Data SINAD IN connectors
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Any test feature may be Enabled or
Disabled as required
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Printing / Capturing Test Results
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Print Directly to an RS-232 Printer
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Print to a Standard Terminal Program
 Allows storage of test results
Note:
Set RS-232 parameters from the system Setup
screen prior to entering the EDACS Option
Automatic test results may be captured and saved
using a terminal program
RS-232 cable connection to a PC is a direct
pin-to-pin connection
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BER 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 Windows
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Applications Library
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EasySweep
This memory resident application
leads the operator and controls the
COM-120B to make many standard
measurements automatically.
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Common Operator Problems
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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 Problems
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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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Questions?
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