pulsed s-parameter measurements using the zva network...

Pulse Profile measurementsRSUK Lunn ver 2.11

Pulsed S-ParameterMeasurements using theZVA network Analyzer

Pulsed Profile measurementsRSUK Lunn ver 2.13

ZVA Advanced Network Analyser


Motivation for Pulsed MeasurementsTypical Applications

� Avoid destruction of DUT due to thermal effects� Power amplifiers not designed for continuous operation� Lack of heat sinking (e.g. on wafer components)

� Measure under real conditions with wireless communications� For example. GSM power amplifiers under burst conditions� Burst mode of TDMA systems and components

� Requirements for Radar and Antenna Measurements� Active array antennas operate in pulsed mode� Scattered pulse incorporates information


Motivation for Pulsed MeasurementsTypical Measurements

� Output power versus frequency and power

� S-Parameter versus frequency and power� Typically S11 and S21� Occasionally S12 and S21 also required

� Pulse profile versus time at a fixed frequency� Power and S21 versus time


Fundamentals of Pulsed MeasurementsWhat is a RF-Pulse in Time Domain

=x

A RF pulse is a multiplication of a rectangular pulse with a CW-RF signal


Fundamentals of Pulsed MeasurementsThe Spectrum of a RF-Pulse

PRF := Pulse Repetition Frequency


Fundamentals of Pulsed MeasurementsWhat is a RF-Pulse in Frequency Domain

Multiplication in time domain = convolution in frequency domain

� spectrum of pulse is shifted by frequency of CW signal

A

ffc

A

t

A

t

A

ffc

A

f

A

t

=x


Fundamentals of Pulsed MeasurementsTypes of Pulsed Measurements

� NWA’s data acquisition time/point > pulse width� Measurement during several pulses

→ narrow bandwidth technique (Average)� Measurement verses power or frequency

� NWA’s data acquisition time/point < pulse width� one data point during one pulse

→ wide bandwidth technique (point in pulse)� Measurement verses power of frequency

� NWA’s data acquisition time/point << pulse width� several data points during one pulse

→ pulse profile technique� Measurement of pulse verses time

timeMeasurementtime / point

timesettling


timesettlingtime

data points

Measurementtime / point


Averaged Pulsed MeasurementsMeasuring the Average (DC Value)

P

f

P

TPmin

BIF

PAVG

BIF:= 1/IFBW

fc


Averaged Pulsed MeasurementsFrequency or power swept measurements

� Measurement at one frequency or power level during several pulsesthe “DC-Value“ of the Pulse Envelope

t

Af1 f1 f2 f2 f3

Sampling time f1

“multiple” pulses…PAVG #f1 PAVG #f2 PAVG #f2

Sampling time f2


Averaged Pulsed MeasurementsDynamic Range considerations

Tp

Ton

Pulse Desensitisation

Measurement example:

P= 0 dBmTon = 1 µsTP = 10 µs

∆ = 20*log(1/10) = -20 dB

- 1 MHz +1 MHz

10 dB/

- 80 dBm

20 dBmMAGdBCH1 10 dB/ REF 0 dBm

CENTER 10 GHz SPAN 3 MHz500 kHz/

CPL

EXT

FST

FI L3k3kFI L3k3k

b2

1

1: - 20. 08 dBm10 GHz

á 0 dBm

20 dB

( )

=

pTPeriodPulseonTWidthPulse

CycleDuty


Averaged Pulsed MeasurementsSpectral Nulling Necessary with previous ZVM/K family

� Placing the Nulls of the IF filter on the first harmonic

+ 8 k Hz

1 0 dB/

- 9 0 dBm

1 0 dBm + 8 k Hz

1 0 dB/

- 8 0 dBm

2 0 dBm

CH1CH2

¯ - 90 dBm¯ - 80 dBm

- 10 dBm- 20 dBm

CENTER 1 GHzCENTER 1 GHz

SPAN 20 kHzSPAN 20 kHz

2 kHz/2 kHz/

CH2 ¯- 80 dBm - 20 dBm

CENTER 1 GHz SPAN 20 kHz2 kHz/

EXT

FST

MAGMAG

dBdB MAGdBb2

FI L100100FI L100100

b1

1 23

1 : - 2 2 . 5 8 d Bm

1 GHz2 : - 0 . 3 4 3 dB

4 . 5 7 5 k Hz3 : - 0 . 2 7 7 dB

- 4 . 5 7 5 k HzBlue trace:Spectrum of T = 218.58 µs→ Tone spacing 4.545 kHz

Red trace:Shape of 3 kHz IF-filter with nullsat 4.545 kHz offset


Averaged Pulsed MeasurementsZVA’s High Selective Filter –No Nulling Required

-60

-50-40

-30

-20

-10

010

2020

1

Ch1 Arb Center 1 GHz Pwr 20 dBm Span 500 kHz

Trc1 a1 dB Mag 10 dB / Ref 20 dBm

a1

-60

-50

-40

-30-20

-10

0

10

2020

2

Ch2 Arb Center 1 GHz Pwr 20 dBm Span 500 kHz

Trc2 a1 dB Mag 10 dB / Ref 20 dBm

a1


Averaged Pulsed MeasurementsExample of desensitisation on a frequency sweep

%10==ssµµ

101CycleDuty

%1==ssµ

µ100

1CycleDuty

%1.0==mss

11CycleDuty µ

RBW=100Hz‘High Selective’

-135

-120

-105

-90

-75

-60

-45

-30

-15

0

1

Pwr 10 dBmCh1 Center 2.22 GHz Span 200 MHz

Trc1Mem4[Trc1]Mem5[Trc1]Mem6[Trc1]

S21S21S21S21

dB MagdB MagdB MagdB Mag

15 dB /15 dB /15 dB /15 dB /

Ref 0 dBRef 0 dBRef 0 dBRef 0 dB

•

Mkr 1Mkr 1Mkr 1Mkr 1

2.1600002.1600002.1600002.160000

GHzGHzGHzGHz

-139.01-114.64-96.634-68.856

dBdBdBdB

S21

Mkr 1

Mkr 1

Mkr 1

Mkr 1

4/24/2007, 11:29 AM

Duty Cycle = CW = 100%~ -140dB

~ -120dB

~ -100dB

~ -65dB


Point in Pulse MeasurementsFrequency or power swept measurements

� Measurement at different frequencies or power levels in differentpulses (point trigger mode with trigger delay τ)

� Each point represents a different frequency or power

t

Af1 f2 f3 f4 f5

f1 f2 f3 f4 f5

t

τ


Point in Pulse MeasurementsMeasurement during one pulse

data sampling happens during the pulse ON state

� sampling time ≈ 1/IFBw

� 1 / IFBW < ton => IFBW > 1/ ton (pulse length)

� maximum IF bandwidth limits the minimum pulse lengthZVR: 35 µs (26 kHz)ZVB: 3 µs (500 kHz)ZVA/T: 1,8 µs (1 MHz)ZVA/T: 0.4 µs (5 MHz) with ZVA-K17 option

(times are typical pure data acquisition time w/o any data processing time)

� e.g. CW-sweep, triggered synchronization

timesettling



Point in Pulse MeasurementsPoint in Pulse Measurements with ZVA-K17

ZVA-K17

�For Point in Pulse measurement with pulse width <430 ns (230 ns)

�IF bandwidth 5 MHz (10 MHz unspecified)

�CW sweep (kind of pulse profile) with resolution of 1,9us (1,6 us)


Point in Pulse MeasurementsTime per Point – The Limitation

settling time data sampling

Time per Point:

� Frequency Sweep: 1µs + 4µs + (3µs...15µs) + (1…2) / IF Bw + 2µs

� CW Sweep: (1…2) / IF Bw + 1,5µs

data processing

pow. settlingfreq. settlingtransfer of instr. data


Point in Pulse MeasurementsLimitations for Pulse Profile Measurements

� Resolution limited by time for data sampling and data processing� Sampling time @ 1 MHz IFBw 1,8 µs� Sampling time @ 5 MHz IFBw 400 ns (ZVA-K17)� Data processing time 1,5 us (CW Sweep)

�Time resolution = sampling time + processing time

> 1,9 us (5 MHz IFBw)


Pulse Profile MeasurementsNarrowband Solution

� Chopping the pulse at different positions with floating pulse delay

� Average pulse measurement of the chopped pulses providesmagnitude and phase information for the chopped section

� Pulse profile has to be reconstructedpulse envelope chopped pulse

floating delay

measurement time (1/IFBW)

t


Pulse Profile MeasurementsNarrowband Solution

�Time consuming setup

�Change of pulse shape requires recalibration

�Requires a periodical, stable pulse signal

�No real time measurement

�Low dynamic range for low duty cycles


Pulse Profile MeasurementsRohde & Schwarz Solution: SSRAM Mode


Pulse Profile MeasurementsRohde & Schwarz Solution: SSRAM Mode

� Sampling data of all wave quantities are stored without filtering into adedicated memory

� Sampling rate = 12,5 ns (system clock of 80 MHz)

� At the end of data recording, digital signal processing e.g. filtering isperformed not by the DSP but by the software “offline”

Advantages:

� No delay by processing time between sampling of to data points

� No limitations for suitable IF filter


Pulse Profile MeasurementsContinous Recording into the SSRAM Memory

-80

-70

-60

-50

-40

-30

-20

-10

0

-40

TRG

1

Freq 1 GHz Pwr 0 dBmCh1 Profile Start -500 ns Stop 500 ns

Trc1 b2 dB Mag 10 dB / Ref -40 dBm

b2


Pulse Profile MeasurementsFeatures of SSRAM Mode

� Memory of 256 kB

� 256*1024*12,5ns = 3,2768 ms

� 3,2 ms of total recording time for S-parameters

� Trigger event sets t = 0

� Continious recording of data

� Behaviour before trigger event can be analysed

� Fast display repetition rate for pulse profile => Tuning possible


Pulse Profile MeasurementsThe Bandwidth

�Does not define the resolution

�Resolution always 12,5 ns (sampling rate of ZVA)

�Defines:� Rise time ( ≅ 1/IFBw)� Maximum ripple frequency on the pulse roof

�Comparable with the bandwidth of an oscilloscope� The Pulse Profile mode works similar as an oscilloscope with a time

resolution of 12 ns and a bandwidth of e.g. 30 MHz


Pulse Profile MeasurementsThe IF Filters for Pulse Profile

� 1MHz, 2 MHz, 5 MHz, 10 MHz, 15 MHz, 20 MHz, 30 MHz

� lower bandwidths not necessary, as normal time or CW sweepcan be used

� slight overshoot of pulse response� 10 MHz, 15 MHz no overshoot� 20 MHz < 3%� 30 MHz < 10%� May lead to small error for output power measurement� Completely compensated for ratio measurements as b2/a1 or S-parameters

because of rationing


Pulse Profile MeasurementsThe Rise Time of the Pulse Profile Filters

0

1

2

3

4

5

6

7

8

0

TRG

1


RBW_10MHz b1 Lin Mag 1 mW/ Ref 0 W

b1 Ref 128.7500 ns 458.88 µW∆Mkr 1 57.5000 ns 3.990 mW

Ref

∆Mkr 1

0

1

2

3

4

5

6

7

8

0

TRGTRG

2




∆Mkr 1

Ref

0

1

2

3

4

5

6

7

8

0

TRGTRG

3




∆Mkr 1

Ref

0

1

2

3

4

5

6

7

8

0

TRGTRG

4




∆Mkr 1

Ref

4/20/2007, 11:12 AM

RBW = 15 MHzRise Time = 41.25 ns





Pulse Profile MeasurementsPulse Profile of a 100 ns DUT

b2 wave shifted withrespect to reference a2wave by group delay of100 ns

S21 after ratioing

-70

-60-50

-40

-30

-20

-100

10

0

TRG

1

Freq 1 GHz Pwr 0 dBmCh1 Profile Start -100 ns Stop 1 µs

Trc1 b2 dB Mag 10 dB / Ref 0 dBm Trc3 a1 dB Mag 10 dB / Ref 0 dBm

b2

-50

-40

-30

-20-10

0

10

20

30

-10

TRG

2


Trc2 S21 dB Mag 10 dB / Ref -10 dB

S21


Pulse Profile MeasurementsPulse Profile of a 100 ns DUT

b2 and S21 aftermathematical delayof 100 ns

-70

-60-50

-40

-30

-20

-100

10

0

TRG

1



b2

-50

-40

-30

-20-10

0

10

20

30

-10

TRG

2


Trc2 S21 dB Mag 10 dB / Ref -10 dB

S21


Pulse Profile MeasurementsPulse Profile Test with ZVA and SMR

� Generation of pulsed RFsignal with pulse generator

� Can be controlled by ZVA

� Pulse Profile andFrequency/Power sweeppossible

� Internal coupler of the ZVAdetermines wave quantities

REF

AUX – User control for list mode

IEEE/LAN

Trigger

Pulsed RF SourceDUT

Signal generatorwith Pulse modulator


Pulse Profile MeasurementsBlock Diagram for Pulsed Stimulus

� Pulsed source fed in front ofcoupler

� Pulsed reference signal

� Calibrated S11 and S21measurements

� Calibration independent ofduty cyle

� Frequency and power sweeppossible

Reflectometer of ZVA

Signal generatorwith Pulse modulator


Pulse Profile MeasurementsZVA, Arb Waveform Generator and Pulse Modulator

RF Switch

Arbitrary WaveformGenerator

DUT


Pulse Profile MeasurementsPulse Profile with Pulsed DUT

Amp: On/Off-3.8

-3.6

-3.4

-3.2

-3.0

-2.8

-2.6

-2.4

-2.2

-3.0

3 of 3 (Max)

Ch2 Profile Start 120 ns Freq 2 GHz Pwr 0 dBm Stop 1.3 µs

Trc4 S21 dB Mag 5 dB / Ref -5 dB Trc8 S11 dB Mag 0.2 dB / Ref -3 dB

Mkr 1Mkr 1

375.0000375.0000

nsns

4.607-3.433

dBdB

S11

Mkr 1

Mkr 1

8/18/2006, 1:23 PM

DUT

Pulsed DC supply


Accuracy:CW Mode, Point in Pulse, Pulse Profile

-6.4-6.3-6.2-6.1-6.0-5.9-5.8-5.7-5.6

-6.0

1

Pwr 0 dBmCh1 Start 2 GHz Stop 8 GHz

Trc1Mem6[Trc1]

S12S12

dB MagdB Mag

0.1 dB /0.1 dB /

Ref -Ref -

Mkr 1

Mkr 1

5.000000

5.000000

GHz

GHz

-6.109115.70-6.074115.81

dB°

dB°

S12

Mkr 1Mkr 1

-10.06-9.06-8.06-7.06-6.06-5.06-4.06-3.06-2.06

-6.06

2


Trc2Mem7[Trc2]

S21S21

dB MagdB Mag

1 dB /1 dB /

Ref -6.Ref -6.

Mkr 1

Mkr 1

5.000000

5.000000

GHz

GHz

-6.065115.38-6.060115.62

dB°

dB°

S21

Mkr 1Mkr 1

-44-42-40-38-36-34-32-30-28

-36

3


Trc3Mem8[Trc3]

S22S22

dB MagdB Mag

2 dB /2 dB /

Ref -36Ref -36

S22

Mkr 1 5.000000 GHz -32.693 dB-90.987°

Mkr 1 5.000000 GHz -32.963 dB-91.028°

Mkr 1Mkr 1

-44-42-40-38-36-34-32-30-28

-36

4


Trc5Mem9[Trc5]

S11S11

dB MagdB Mag

2 dB /2 dB /

Ref -36 dBRef -36 dB

Ca?

S11

Mkr 1 5.000000 GHz -31.431 dB112.52°

Mkr 1 5.000000 GHz -32.005 dB111.98°

Mkr 1Mkr 1

-40-35-30-25-20-15-10-50

-15

TRG

5


Trc10Trc11

S21S11

dB MagdB Mag

5 dB /10 dB /

Ref -15 dBRef 0 dB

Ca?Ca?

S21

Mkr 1 281.2500 ns -31.579 dB111.61°

Mkr 1 281.2500 ns -6.105 dB115.77°

Mkr 1

Mkr 1

11/3/2006, 7:37 AM

Traces:Point in Pulse

Mem Traces:CW Mode

Pulse Profile


Pulse Profile MeasurementsPulse Train with Changing Duty Cycle and Amplitude

-51-41

-31-21

-11

-19

1929

0

TRG

1

Freq 1 GHz Pwr 0 dBmCh1 Profile Start -23.1 µs Stop 272 µs

Trc1 a1 dB Mag 10 dB / Ref 0 dBmM1M2

17.061355.0400

µsµs

3.2118.128

dBmdBm

a1

M1M2

51015202530354045

25

TRG2

Freq 1 GHz Pwr 0 dBmCh1 Profile Start -23.1 µs Stop 272 µs

Trc2 S21 dB Mag 5 dB / Ref 25 dB• M1

M217.061355.0400

µsµs

9.8835.460

dBdB

S21

M1M2

10/4/2007, 5:57 PM


Pulse Profile MeasurementsPulse Train with AM Modulation

-20-15-10-505

101520

0

TRG1

Freq 1 GHz Pwr 0 dBmCh1 Profile Start -10 µs Stop 1 ms


b2

6

8

10

12

14

16

18

20

22

14

TRG

2

Freq 1 GHz Pwr 0 dBmCh1 Profile Start -10 µs Stop 1 ms

Trc2 S21 dB Mag 2 dB / Ref 14 dB

S21

10/4/2007, 6:12 PM


-8-6-4-202468

0

TRG

1

Freq 1 GHz Pwr 0 dBmCh1 Profile Start -2 µs Stop 8 µs

Trc1Trc2

a1a1

RealImag

2 mW/2 mW/

Ref 0 WRef 0 W

a1

-70-60-50-40-30-20-10

0100

TRG

2


Trc3Trc5

a1b2

dB MagdB Mag

10 dB /10 dB /

Ref 0 dBmRef 0 dBm

a1

Mkr 1 1.0025 µs -0.629 dBmMkr 2 5.9888 µs -1.012 dBmMkr 1 1.0025 µs 7.234 dBmMkr 2 5.9888 µs 6.488 dBm

Mkr 1 Mkr 2Mkr 1 Mkr 2

-15-10-505

10152025

0

TRG

3


Trc4 S21 dB Mag 5 dB / Ref 0 dB Trc6 S21 Phase 45° / Ref 0°

S21 Mkr 1 1.0025 µs 14.531°Mkr 2 5.9888 µs -123.62°

Mkr 1 1.0025 µs -7.518 dBMkr 2 5.9888 µs -7.154 dB

Mkr 1

Mkr 2

Mkr 1 Mkr 2

1/9/2008, 11:56 AM

Pulse Profile MeasurementsPulse Train with FM Chirp Modulation

Real and Imag signalsAre displayed at the

reference

The magnitude of theReference a1 and

Measure channel b2.B2 is time shifted,

See next slide(DUT is a 50ns delay

Line)

The S-Parameters canBe calculated for

Both the magnitude andPhase from a1 and b2


Pulse Profile MeasurementsPulse Profile Measurements with ZVA-K7

� For Pulse Profile Measurement

� Includes ZVA-K17� For Point in Pulse measurements versus frequency and power� Minimum pulse width 420 ns

� For Pulse Profile measurements with resolution of 12,5 ns andIFBw of 10 MHz� Wider IFBw up to 30 MHz (unspecified) available beginning 2007, with upgraded

ZVA hardware


Fundamentals of Pulsed MeasurementsSummery of Pulsed Measurements

� Average Pulse Measurement (App.-Note 1EZ52)� Measurement versus power and frequency� Minor requirements for NWA hardware (ZVA-K4, ZVA-B16)

� Point in Pulse Measurement (more accurate)� Measurement versus power and frequency� Requires sampling time < pulse width (ZVA-K4, ZVA-K17, ZVA-B16)

� Pulse Profile Measurement� Measurement of the pulse versus time� Requires sampling time << pulse width (ZVA-K7, ZVA-B16)


timesettling


timesettlingtime

data points

Measurementtime / point


Thank You for yourattention!

Questions?

pulsed s-parameter measurements using the zva network...

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