What Have You Been Missing In Your
Pulsed VNA Measurements?
8 Oct 2013
13:00h - 13:40h
Presented by: Bob Buxton
EuMW Seminars 2013
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Confidence
on the cutting edge
Pulsed
Measurements
EuMW Seminars 2013
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Agenda
• Background
• Applications
• Measurement Overview
• Common Test Challenges
• Pulse Measurement Methodologies
• Wideband method
• Narrowband method
• High-Speed digitizer method (VectorStar’s innovative architecture)
• Measurement Tips and Considerations
• Calibration
• Minimizing Uncertainties
• Summary
EuMW Seminars 2013
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Common Pulse Applications
• Measure the reaction of a DUT to a pulsed RF stimulus
– E.g., Radar: transmitter, receiver, or both
• Measure the reaction of a DUT to pulsed IV (and pulsed RF?)
– High power density semiconductors (SiC, GaN)
– Traveling-wave-tube amplifiers (TWTAs)
– Must synchronize with (ext sync) or control DC bias (pulse gen)
• Part of active device test suite
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S-parameters
1 dB compression point
NF, higher order distortion products, harmonics
IMD, IP3 (third-order intercept point)
EuMW Seminars 2013
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Radar
Courtesy of LCRS
Courtesy of Telematics News
Courtesy of Raytheon
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Radar
Factor
Pulse shape
Pulse width
Radar Characteristic Affected
Range accuracy, range resolution
Range resolution, maximum range, minimum
detection range
Pulse repetition frequency
Maximum unambiguous range, detection
probability
Fundamental frequency
Directivity, target resolution, propagation
loss, size of equipment
Range resolution
Target masking, range resolution
Probability of detection, angular resolution
Maximum detection range
Maximum detection range, physical size
Maximum detection range
Maximum detection range
Chirp frequency bandwidth
Chirp pulse ripple/time sidelobes
Scan rate and beamwidth
Receiver sensitivity
Transmitter power
Average gain
Radar cross section
Radar trends
Narrower pulses
1 us, 150 m
50 ns, 7.5 m
Wide range of PRF
Lower, longer range
Higher, shorter
Higher frequencies
Antenna size, bandwidth,
smaller target sizes
• Key measurement parameters:
– Min pulse width/resolution, record length, range of PRFs, frequency range
EuMW Seminars 2013
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Pulsed IV (and RF)
• Used with TWTAs to reduce power consumption
• Used at wafer-level to avoid thermal effects
– Memory \trapping effects
Thermal
•
Electrical
Key measurement parameters:
– Pulse profile and min measurement width, point-in-pulse resolution, pulse-topulse and PRF range
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Agenda
• Background
• Applications
• Measurement Overview
• Common Test Challenges
• Pulse Measurement Methodologies
• Wideband method
• Narrowband method
• High-Speed digitizer method (VectorStar’s innovative architecture)
• Measurement Tips and Considerations
• Calibration
• Minimizing Uncertainties
• Summary
EuMW Seminars 2013
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Pulse Characteristics and Definitions
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Measurement Overview
Three types of stimulus:
*
•
*
Three types of measurements:
Pulse Profile (PP)
Point-in-Pulse (PIP)
Sweep time
Sweep freq
or power
Pulse-to-Pulse (P2P)
Sweep time
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Agenda
• Background
• Applications
• Measurement Overview
• Common Test Challenges
• Pulse Measurement Methodologies
• Wideband method
• Narrowband method
• High-Speed digitizer method (VectorStar’s innovative architecture)
• Measurement Tips and Considerations
• Calibration
• Minimizing Uncertainties
• Summary
EuMW Seminars 2013
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Common Test Challenges
• Too many test method trade-offs
• Need for better analysis tools
• Monitor pulse behavior over longer times
• Eliminating measurement setup errors
• Timing and synchronization issues
(in measurement or calibration)
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Agenda
• Background
• Applications
• Measurement Overview
• Common Test Challenges
• Pulse Measurement Methodologies
• Wideband method
• Narrowband method
• High-Speed digitizer method (VectorStar’s innovative architecture)
• Measurement Tips and Considerations
• Calibration
• Minimizing Uncertainties
• Summary
EuMW Seminars 2013
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Time – Frequency Domains
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Traditional Trade-offs
Wideband Method
Trade-off: minimum pulse width limitations
Historically, wideband pulse
measurement is used when most
pulse energy is contained in the
receiver BW. As pulse widths
narrow (e.g., 1 µs), users are
forced to move to narrowband
techniques.
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Agenda
• Background
• Applications
• Measurement Overview
• Common Test Challenges
• Pulse Measurement Methodologies
• Wideband method
• Narrowband method
• High-Speed digitizer method (VectorStar’s innovative architecture)
• Measurement Tips and Considerations
• Calibration
• Minimizing Uncertainties
• Summary
EuMW Seminars 2013
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Traditional Trade-offs
Narrowband Method
Trade-offs:
− Dynamic range penalty
− No pulse-to-pulse capability
EuMW Seminars 2013
Dynamic range degradation = 20*log[duty cycle]
 1% duty cycle = 40 dB D/R reduction!
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Common Test Challenges
• Too many test method trade-offs
• Need for better analysis tools
• Monitor pulse behavior over longer times
• Eliminating measurement setup errors
• Timing and synchronization issues
(in measurement or calibration)
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MS4640B now with:
• Option 035 IF Digitizer
• Option 042 PulseViewTM
• Pulse Modulator Test Sets
(required for RF pulsing)
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Eliminate Trade-offs!
• Option 035 IF Digitizer enables
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EuMW Seminars 2013
200 MHz Receiver bandwidth
Measurement resolution as fine as 2.5 ns
Independent measurement IF receiver windows
500 ms record lengths
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Common Test Challenges
• Too many test method trade-offs
• Need for better analysis tools
• Monitor pulse behavior over longer times
• Eliminating measurement setup errors
• Timing and synchronization issues
(in measurement or calibration)
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The True View
• What have you been missing?
2.5 ns resolution
15 ns resolution
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Common Test Challenges
• Too many test method trade-offs
• Need for better analysis tools
• Monitor pulse behavior over longer times
• Eliminating measurement setup errors
• Timing and synchronization issues
(in measurement or calibration)
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The True View
Example: 100 ms PRI (100 µs, 900 µs period), 10 ns resolution, 30 MHz IFBW
Record lengths up
to 500 ms --
At full resolution!
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Common Test Challenges
• Too many test method trade-offs
• Need for better analysis tools
• Monitor pulse behavior over longer times
• Eliminating measurement setup errors
• Timing and synchronization issues
(in measurement or calibration)
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Measurement Confidence
• Visual representation of signals and
measurements
• Simple generator configuration
– Varying types of pulses generated
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•
•
•
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Singlet
Doublet
Triplet
Quadruplet
Burst
– Change labels for better test
descriptors
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Measurement Confidence
• Simple measurement
configuration
– Adjustments for each receiver
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Measurement Confidence
• Use Zoom Marker to double
check test setup
• Drag vertical lines for start and
stop zoom area
• Drag vertical lines as time
markers
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Industry-first Instant Results
• Make measurement
adjustments and see the
results instantly
• No need to toggle back
and forth between
configuration windows
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Common Test Challenges
• Too many test method trade-offs
• Need for better analysis tools
• Monitor pulse behavior over longer times
• Eliminating measurement setup errors
• Timing and synchronization issues
(in measurement or calibration)
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Independent
Rcvr Windows
Coupled IF Receiver
Windows
• Measurement results may identify unexpected behavior
• Delay start of b measurement to
2
– For example, there may be measurement delays (from
group delay,
properly align S21 result
long test cables, …) which can affect ratio measurements
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Agenda
• Background
• Applications
• Measurement Overview
• Common Test Challenges
• Pulse Measurement Methodologies
• Wideband method
• Narrowband method
• High-Speed digitizer method (VectorStar’s innovative architecture)
• Measurement Tips and Considerations
• Calibration
• Minimizing Uncertainties
• Summary
EuMW Seminars 2013
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Calibration
• Power Calibrations
• Receiver Calibrations
• User RF Calibrations
– No stimulus pulsing
– Stimulus pulsing
– Receive-side modulation/gating
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Minimizing Uncertainties
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•
•
•
Time
Shaping
Calibration
Minimizing uncertainties
– Increase averaging or reduce IFBW
– Maximize power (while avoiding compression)
– Filtering
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Summary
• Background
• Applications
• Measurement Overview
• Common Test Challenges
• Pulse Measurement Methodologies
• Wideband method
• Narrowband method
• High-Speed digitizer method (VectorStar’s innovative architecture)
• Measurement Tips and Considerations
• Calibration
• Minimizing Uncertainties
EuMW Seminars 2013
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Equipment Selection Criteria
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•
•
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IF bandwidth – sampling rate
Min measurement and timing resolution
Measurement method trade-offs (e.g., dynamic range reduction)
# of pulse generators available
– Pulse generation signal formats available (e.g., doublets, bursts, …)
– Min pulse width
• Pulse modulator performance (e.g., on-off ratio, rise-time, …)
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What Have You Been Missing In Your
Pulsed VNA Measurements?
• Innovative high-speed digitizer
architecture
• Industry’s highest resolution
measurements
• Longest record lengths
• Independent measurement
receiver windows
• Intuitive graphical configuration tool
• Instant results on measurement
parameter changes
EuMW Seminars 2013
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CALL ANRITSU FIRST
FOR ANSWERS!
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