Software Defined Radio Analysers for LMR Testing
Lex Grubner
Managing Director
RF Test Solutions Ltd
May 2010
Worldwide LMR Unit Numbers
35.0 M
WW LMR Handset & Mobile
30.0 M
25.0 M
Cumulative Digital Radios
20.0 M
Cumulative "Old" Type of
Radios:
15.0 M
24.7 M Analog Radios in Use
60% of total
10.0 M
5.0 M
16.1 M Digital Radios in Use
40% of total
0.0 M
2004
2005
2006
2007
2008
2009
2010
Target Application for LMR Test Sets
Research &
Development
Manufacturing
Test
Bench Repair
Repair PCB to
component level
“I” Level Test
•Green = Likely all you need
•Amber = May only be part what you need
•Red = Not likely to meet your need
Repair to PCB or
major part level
“O” Level Test
Confirm if Radio has
fault
Usage model for LMR Test Sets
Bench Repair
Fault tracing & component level
repair on a circuit board
10% of job volume
Average repair time 1- 2 hours
28% of test set time usage
“I” Level Test
Minor repair - replace board/part
to get radio back in service
30% of job volume
Average repair time 0.5 – 1 hours
44% of test set time usage
“O” Level Test
Quick go/no-go check of radio
60% of job volume
Average repair time 0.25 hours
28% of test set time usage
LMR Test Set Situation in NZ
 Personally responsible for selling over 200 units for
analogue radio test.
 Estimated 300 - 400 analogue radio test sets in NZ.
 85% over 10 years old.
 20% over 20 years old.
 Estimated 30 SDR (digital capable) test sets.
What is Changing
 Analog to digital modulation.
 More Information same narrow bandwidth.
 More open standard deployments (P25, TETRA,
DMR etc).
 Less proprietary standard deployments (SmartNet,
EDACS etc).
 Radios operate in integrated network.
What is needed today in a LMR Test Set
• RF performance needs to be even better.
• Must support digital modulation.
• Must emulate network enough for radio to operate.
• SDR architecture to provide the modulation flexibility
& protocol analysis power.
• A whole new set of measurement techniques.
Architecture of an Analogue Test Set
Internals of an Analogue Test Set
Architecture of a SDR Test Set
Internals of a SDR
Test Set
Primary Advantages of a SDR Test Set
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Smaller and Lighter.
More reliable (fewer components).
Lower Power Consumption.
Protocols and feature upgrades managed by user.
Connectivity and Networking.
Greater configuration flexibility (not limited by
hardware paths).
 Cost.
Smaller and Lighter
Adding Protocols & Features
To This!
Cost
 In 1990 a HP8920A base system = NZ$30,000.
 Inflation adjusted over 20 years = NZ$48,000 today.
 A R8000 base system today = NZ$26,000.
 A 1990 loaded HP8920A = NZ$40-45,000.
 Inflation adjusted = NZ$64–72,000 today.
 3GHz R8000 Every HW option + DMR & P25 =
NZ$48,500.
Challenges Testing Digital Radios
 Computer, networking and software skills as important
as RF skills (problem may not be the radio).
 Learning & understanding SDR architectures, and
Digital Modulation.
 Manufacturer Specific RSS (Radio Service Software)
needed to put radio in test modes.
Terminology is Changing
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RF Carrier Power
Deviation (FM)
Mod Depth (AM)
SINAD
S/N
Distortion
Can make CW
Measurements
 Simple Single Tone Audio
Assessment
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Envelope Power (NXDN FDMA)
Slot Power (DMR TDMA)
BER
FSK Error (DMR)
Modulation Fidelity (P25/NXDN)
Eye Diagrams
Constellation Displays
Modulation ALWAYS exists
Each Digital Standard has unique
test patterns.
 NAC (P25)
 Colour Code (DMR).
 Voice loopback.
Example DMR Test Screen
Example P25 Test Screen
Example Voice Record/Playback Screen
What to Look for in a SDR Test Set
 Good RF performance.
 Sufficient coverage of analogue/legacy signaling formats
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(CTCSS, POCSAG, DTMF, CDCSS etc).
Support of digital formats of interest (DMR, P25, NXDN, LTR
etc).
Large display to view set up and results at same time.
Adequate sensitivity for off air measurements.
Fast, low noise Spectrum Analyser + TG with RL/DTF.
Easily transportable & low power consumption.
Questions?
Thank you (and please visit our stand!).