ITMAR WG 2012

In-Band Test Methodologies for
Advanced Radios (ITMAR)
briefed by
Ken Carrigan
E3 Spectrum Supportability Branch
[email protected]
W: 540-653-2190
21 April 2012
Distribution Statement A: Approved for public release ID# 3343 ; Distribution is unlimited.
Agenda
 In-Band Receivers Issues
 Test Standards and Shortcomings
 Characterizing Receiver Front Ends
 Performance Metrics
 Quick Review of Test Procedures
 Examples Proposed Methods
 Way Ahead Towards Generalizing and
Harmonizing
Distribution Statement A: Approved for public release; Distribution is unlimited.
2
Issues Affecting Receivers
 Most EMI problems occur in-band to receivers
 Significant RF System growth by DOD
 Ever increasing use of wide band receivers
 Wide band sensitive receivers can be
degraded, or burned out, by intra-inter High
Power RF emitters
Distribution Statement A: Approved for public release; Distribution is unlimited.
3
Military Wideband Receiver Systems
 Equipment that Utilizes the Electromagnetic
Spectrum
– SATCOM, JTRS, LINK 16, LINK 22
– Mobile User Objective System (MUOS), Wideband
Networking Waveform (WNW), Soldier Radio
Waveform (SRW)
– Radars (TPS, TPQ, SPS, SPN, SPQ, G/ATOR, VSR,
even Helmet Mounted Radar System -HMRS)
– EW (SLQ-32, VLQ-12(V), Surface Electronic Warfare
Improvement Program -SEWIP)
Distribution Statement A: Approved for public release; Distribution is unlimited.
4
Complex Receiver Systems

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Carrier Sense Multiple Access With Collision Avoidance
(CSMA/CA)
Frequency Hopping Spread Spectrum (FHSS),
Direct Sequence Spread Spectrum (DSSS)
Multiple Input Multiple Output (MIMO) systems
Beam Steer Antenna Technology (spatial diversity)
IEEE 802.22 in-band and out-of-band Sensing of Spectrum
– Cognitive Radios
Dynamic Frequency Selection (DFS) and Dynamic
Spectrum Access (DSA)
Ultra Wide Band (UWB) Impulsive radio…
Distribution Statement A: Approved for public release; Distribution is unlimited.
5
Receiver Test Standards

MIL-STD-461F
–
10 Dec 2007
– RS103 now applies ‘1 kHz pulse modulation, 50% duty’ to
case/cabinet in-band to subs and ships
– CS103 ‘Conducted Emissions, Antenna port, Intermodulation,
15 kHz to 10 GHz
– CS104 ‘Conducted Emissions, Antenna port, Rejection of
Undesirable Signals, 30 Hz to 20 GHz
– CS105 ‘Conducted Emissions, Antenna Port, Cross Modulation,
30 Hz to 20 GHz

MIL-STD-464C, External RF EME’s, Inter/Intra EMC
Distribution Statement A: Approved for public release; Distribution is unlimited.
6
EME Situation for Receivers

Effects of typical EME on receiver front end.
In-band, adjacent channel, and out-of-band.
Non-Linear
Distortions
RF Tuned
BW
Results Shown for 10 dB Gain, IIP3 = 60 dBm
(Ultra High Quality) LNA
Inadequate filtering before LNA can result in “In-Band” interference
Distribution Statement A: Approved for public release; Distribution is unlimited.
7
Problem Areas
RS103 testing is not designed for input to antennas
 CS103-105 does not address the antenna, long
transmission lines, waveguides, antenna diversity
characteristics, or cognitive awareness systems

– Procurement activity must specify these conducted
susceptibility tests in order for testing to occur
– Pass/Fail requirements, methods, and limits missing
– Takes Experienced E3 Engineers to make up contractual
requirements in advance of procurements
Distribution Statement A: Approved for public release; Distribution is unlimited.
8
Characterizing Receivers
 All receivers have generalized front end
characteristics, it’s where degradation begins:
–
–
–
–
In-Band (IB)
Adjacent Channel (AC)
Selectivity Bandwidth (SB)
Out-Of-Band (OOB)
OOB
f4
AC
f1 – f2 = Δf12
Δf12
f3
Tunable Range
(SB)
f
2
f
1
60dB
Non-Linear Elements
Mixers, signal limiters, LNAs,
A/D, current limiters,
detectors, gain controls, any
semiconductor in RF chain
In-Band
(IB)
Distribution Statement A: Approved for public release; Distribution is unlimited.
9
General Receiver Testing Concerns
CS103,104,105 were developed for legacy systems
back in 1980’s, when narrowband RF systems
dominated, and tests were never updated to address
today and tomorrows advanced RF technologies
 A more unified concept is needed as an overall
approach for testing receivers to include an
architectural adaptable type of philosophy
 We need to move “smartly” to develop test methods
to adequately address all receiver types
 DD-1494 regulatory processes maybe of some help

Distribution Statement A: Approved for public release; Distribution is unlimited.
10
Proposed Applicability
CS107/RS104
– Test for the rejection of
undesirable signals
 Receiver front-end susceptibility requirement is
applicable across the receivers tuning range plus 5
times the largest receiving bandwidth on either side
of the tuning range.
 Applicable to equipment that has a receiver tuning
range, or channel bandwidth, =>40MHz.
 Applicable to spread spectrum, PN modulation,
Frequency Agile, and Cognitive, Dynamic Spectrum
radios.

Distribution Statement A: Approved for public release; Distribution is unlimited.
Purpose of Wideband Tests
 Test is used to verify the ability of the EUT to
operate in the presence of inter or intra system
RF emissions that are out-of-band, adjacent to,
and in-band with the EUT receiver input.
 If the limit can not be met then testing should
identify the threshold level in performance
degradation and frequency ranges, similar to
distance threshold of RE101.
Distribution Statement A: Approved for public release; Distribution is unlimited.
Investigating Modulation Methods
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System lookup tables of dependants for required signal
modulations (use of Advanced Waveform Generator (AWG),
Vector Signal Generator (VSG), etc.)
Use modulation of EUT receiver? Plus modulation 1 & 2 as
default? Frequency range specific modulations? Need ideas.
Tables for receivers
Modulation
Receiver type
1,2,4,6,7
Detection
Threshold
I/N
B EW
C Comm: Analog
D Comm: Digital
1-7
1,3,5
1,5
AGC
MTD
Eb/No
E Receive only
1, 3
BER
A Radar
Modulation
F …
1
50% Duty, 1kHz, AM
2
10MHz OFDM 64QAM
3
FM, 10kHz, 80% modulation
4
50uS pulse, 200PRI
5
FSK, 5kHz
6
2uS, 10kHz
7
LFM 40MHz
8
…
Examples Only
Examples Only
Distribution Statement A: Approved for public release; Distribution is unlimited.
14
Proposed Procedures
 Limit levels can be based off of EMV Tables in MIL-
STD-464 or tailored by MIL-HDBK-235
 Levels can then plug into table for computed
susceptibility requirements (V/m, and dBm)
 Modulation types are selected from tables
 Set EUT ‘Signal source’ at Threshold of Detection
for performance metric used for susceptibility
 Scan rates according to RS103 Table III and
frequency ranges as computed by Limit table
Distribution Statement A: Approved for public release; Distribution is unlimited.
15
Proposed Setups - Calibration
•Adjust AWG with RF amplifier to produce required
dBm level at Spectrum Analyzer (EUT under test)
50Ω
Ohm
EUT Stimulator or Target
Generator
RF Amplifier
Isolator or
Directional
Coupler
Directional
Couplers
Advanced Waveform
Generator
50Ω
Ohm
20dB
Spectrum
Analyzer
Distribution Statement A: Approved for public release; Distribution is unlimited.
Proposed Setup – CS107 Test
 EUT test source produces threshold of
detection at performance levels of EUT
Transmitter or
transceiver for EUT
Slowly increase RF to
required dBm levels,
monitor and record
100dB Variable
Attenuator
RF
Amplifier
Isolator
6dB
Directional
Couplers
Advanced
Waveform
Generator
Interference
Source
20dB
Spectrum
Analyzer
Ant
EUT
Distribution Statement A: Approved for public release; Distribution is unlimited.
Proposed Test Setup – RS104
 If EUT antenna has a ‘port’, monitor radiated
fields for required dBm levels.
 If EUT antenna is fixed, monitor E-Field and use
V/m limit.
E-Field
Meter
Adjustable
100dB
Transmitter or
Transceiver
for EUT
Directional
Coupler
RF
Amplifier
Advanced
Waveform
Generator
20dB
EUT
Spectrum
Analyzer
Distribution Statement A: Approved for public release; Distribution is unlimited.
Proposed Data Presentation
 Threshold of Degradation; Results (Receiver D, X meters)
Tunable
Band
OOB
10dBm
OOB
Limit Line
-30dBm
Test data
In-Band
10MHz WNW
Distribution Statement A: Approved for public release; Distribution is unlimited.
520MHz
460MHz
400MHz
340MHz
280MHz
220MHz
160MHz
-80dBm
100MHz
CS107 Injection level (dBm)
Modulation 1
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Test Example of System A
The EUT test was conducted in accordance with the
RS103 procedures defined in MIL-STD-461F(DoD) for
Topside 200V/m levels with an antenna connected.
 To avoid in-band damage to the device-under-test the
radiated susceptibility testing was accomplished at a
much lower level than the applicable RS103 limit.
 The field-intensity level was increased during
subsequent test runs until the 200V/m RS103 limit
was reached, or a susceptibility was observed.
 Continuous Wave and Pulse Modulation was used to
somewhat simulate existing shipboard systems.

Distribution Statement A: Approved for public release; Distribution is unlimited.
Results of System A

The system was receiving 6dB S/N on red channels
while testing was conducted
Freq Range
200V/m
Requirement
Z1-Z4
X1-X9
Z
Y1-Y3
Two Receiver Links tested
Y
X
RF Band
Pass filter
Level (V/m)
X1
71
X2
200
X3
70
X4
158
X5
200
X6
47
X7
16
X8
32
X9
22
Y1
2
Y2
3
Y3
6
Z1
200
Z2
200
Z3
200
Z4
200
Distribution Statement A: Approved for public release; Distribution is unlimited.
Way Ahead
 Arrange Meetings, Webex, Webinars
 Feedback from Industry/Government on
requirements, methods, limits, data
 Are the Tailoring Limits valid requirements?
 Are Test Methods achievable?
 Request others validate by laboratory testing
 Comparing/Sharing of test data, formats
 Publish Documents/Reports (IEEE EMC,
Journals, Conferences, etc)
Distribution Statement A: Approved for public release; Distribution is unlimited.
22
QUESTIONS?
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