1 eumw seminars 2013 what have you been missing in your pulsed vna measurements? 8 oct 2013 13:00h -...
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1EuMW Seminars 2013EuMW Seminars 2013
What Have You Been Missing In Your Pulsed VNA Measurements?
8 Oct 201313:00h - 13:40h
Presented by: Bob Buxton
3EuMW Seminars 2013
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
4EuMW Seminars 2013
• 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– S-parameters– 1 dB compression point– NF, higher order distortion products, harmonics – IMD, IP3 (third-order intercept point)
Common Pulse Applications
6EuMW Seminars 2013
Radar
• Key measurement parameters:– Min pulse width/resolution, record length, range of PRFs, frequency range
Factor Radar Characteristic AffectedPulse shape Range accuracy, range resolutionPulse width 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
Chirp frequency bandwidth Range resolutionChirp pulse ripple/time sidelobes Target masking, range resolutionScan rate and beamwidth Probability of detection, angular resolutionReceiver sensitivity Maximum detection rangeTransmitter power Maximum detection range, physical sizeAverage gain Maximum detection rangeRadar cross section Maximum detection range
Radar trendsNarrower pulses
1 us, 150 m50 ns, 7.5 m
Wide range of PRFLower, longer rangeHigher, shorter
Higher frequenciesAntenna size, bandwidth, smaller target sizes
7EuMW Seminars 2013
• Used with TWTAs to reduce power consumption
• Used at wafer-level to avoid thermal effects – Memory \trapping effects
Thermal
Pulsed IV (and RF)
• Key measurement parameters:– Pulse profile and min measurement width, point-in-pulse resolution, pulse-to-
pulse and PRF range
Electrical
8EuMW Seminars 2013
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
10EuMW Seminars 2013
• Three types of measurements:
Pulse Profile (PP) Point-in-Pulse (PIP)
Pulse-to-Pulse (P2P)
Sweep time
Sweep time
Sweep freqor power
• Three types of stimulus: Measurement Overview
* *
11EuMW Seminars 2013
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
12EuMW Seminars 2013
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)
13EuMW Seminars 2013
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
15EuMW Seminars 2013
Traditional Trade-offsWideband MethodTrade-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.
16EuMW Seminars 2013
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
17EuMW Seminars 2013
Traditional Trade-offsNarrowband MethodTrade-offs:− Dynamic range penalty− No pulse-to-pulse capability
Dynamic range degradation = 20*log[duty cycle] 1% duty cycle = 40 dB D/R reduction!
18EuMW Seminars 2013
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)
19EuMW Seminars 2013
MS4640B now with:• Option 035 IF Digitizer• Option 042 PulseViewTM
• Pulse Modulator Test Sets (required for RF pulsing)
20EuMW Seminars 2013
Eliminate Trade-offs!
• Option 035 IF Digitizer enables– 200 MHz Receiver bandwidth– Measurement resolution as fine as 2.5 ns– Independent measurement IF receiver windows– 500 ms record lengths
21EuMW Seminars 2013
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)
23EuMW Seminars 2013
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)
24EuMW Seminars 2013
The True View
At full resolution!
Example: 100 ms PRI (100 µs, 900 µs period), 10 ns resolution, 30 MHz IFBW
Record lengths up to 500 ms --
25EuMW Seminars 2013
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)
26EuMW Seminars 2013
Measurement Confidence• Visual representation of signals and
measurements
• Simple generator configuration– Varying types of pulses generated• Singlet• Doublet• Triplet• Quadruplet• Burst
– Change labels for better test descriptors
27EuMW Seminars 2013
• Simple measurement configuration– Adjustments for each receiver
Measurement Confidence
28EuMW Seminars 2013
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
29EuMW Seminars 2013
Industry-first Instant Results
• Make measurement adjustments and see the results instantly• No need to toggle back
and forth between configuration windows
30EuMW Seminars 2013
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)
31EuMW Seminars 2013
Coupled IF Receiver Windows
• Measurement results may identify unexpected behavior– For example, there may be measurement delays (from group delay,
long test cables, …) which can affect ratio measurements
• Delay start of b2 measurement to properly align S21 result
Independent IF Rcvr Windows
32EuMW Seminars 2013
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
33EuMW Seminars 2013
Calibration• Power Calibrations• Receiver Calibrations• User RF Calibrations– No stimulus pulsing– Stimulus pulsing– Receive-side modulation/gating
34EuMW Seminars 2013
Minimizing Uncertainties• Time• Shaping• Calibration• Minimizing uncertainties– Increase averaging or reduce IFBW– Maximize power (while avoiding compression)– Filtering
35EuMW Seminars 2013
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
36EuMW Seminars 2013
Equipment Selection Criteria• 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, …)
37EuMW Seminars 2013
• 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
What Have You Been Missing In Your Pulsed VNA Measurements?