TIME-DOMAIN MEASUREMENT SYSTEM FOR IMPULSE NOISE

CHARACTERIZATION

Salvador Verdaguer

Ferran Silva

Electromagnetic Compatibility Group (GCEM). Technical University of Catalonia (UPC)Campus Nord, Edifici C4. c/ Jordi Girona 1-3. 08034 Barcelona SPAIN salva@eel.upc.es

1.- Transient phenomena: measurement challenge

2.- First option: spectrum analyzers and EMI receivers

4.- Second option: wideband digital oscilloscopes

5.- Proposed solution: a hybrid architecture

6.- Signal path in frequency domain

9.- Real-transient measurements

10.- Conclusions

Index

Transient phenomenaTransient measurement and characterization is necessary to determine the effect of impulsive interferences on new electronic systems

• High frequency

• Short duration

• Low level

Transient characteristics

Which is the most suitable equipment to measure them ?

● Broad frequency range ● High sensitivity ● Wide dynamic range

Spectrum Analyzers and EMI Receivers

• Frequency sweep operation:

Too slow

Does not provide time information

• Trigger system usually asynchronous

• Zero-span operation:

# Samples limited to # points on screen

e.g.: RBW = 1 MHz fS = 2 MHz

250 μs on a 500-point screen

Real spectrum

Measured spectrum

● Frequency range > 3 GHz ● Sample memory > 32 MB ● Versatile trigger ● Measurement accurate in amplitude and phase

Wideband Digital Oscilloscopes

• Large bandwidth used in measurement process

higher noise level

• 8-bit ADC

narrow dynamic rangeA/D

f

• High sampling frequencies

€€€

e.g.: fS = 5 GHz needed for 2,4 GHz ISM band

Spectrumanalyzer orEMI receiver

Proposed solution

Acquisition

System

(digitizer

board)

Frequency-domain stageHigh frequencyHigh sensitivity

Time-domain stageLarge dynamic range > 10 bit

Deep sample memory > 32 MB

Proposed solution: general architecture

9 kHz – 3 GHz

RBW 1 MHz

ADC 14 bit

32 MB

64 MS/s

Trigger stage

IF OUTPUT

R&S ESPI3 in Zero span mode

NI PXI 5620

Signal path in frequency domain

f

f

f

f

CFRBW = 1 MHzZero span

output

IF output

Digitizer system output

250 μs on-screen

IF = 20,4 MHz

>1 second captured

Real-transient measurement

12 V 2 m

CF = 50 MHz

RBW = 1 MHz

Relay spark

Real-transient measurement

-0.05 -0.04 -0.03 -0.02 -0.01 0 0.01 0.02 0.03 0.04 0.050.006

0.008

0.01

0.012

0.014

0.016

0.018

0.02

t[s]

|E| [

V/m

]

1 MHz BW centered at 100 MHz

FM radio broadcast waveforms 82 dBuV/m

86 dBuV/m

4.4 kV ESD

Transient in time domain

Real-transient measurement

-2.5 -2 -1.5 -1 -0.5

x 10-4

0

0.005

0.01

0.015

0.02

0.025

t [s]

|E| [

V/m

]

Clean RF band, no waveforms present

88 dBuV/m

4.4 kV ESD

1 MHz BW centered at 130 MHz

Transient in time domain

Real-transient measurement

-3 -2 -1 0 1 2 3

x 10-4

0

0.5

1

1.5

2

2.5

3

3.5

4

4.5

x 10-4

t [s]

|E| [

V/m

]

4.4 kV ESD

Quiet GSM channel

34 dBuV/m

54 dBuV/m

1 MHz BW centered at 1803 MHz

Transient in time domain

Real-transient measurementGSM Incoming call

Signal seek in frequency domain:

100 MHz Span, MAX Hold

1803 MHz GSM channel

1.75 1.76 1.77 1.78 1.79 1.8 1.81 1.82 1.83 1.84 1.85

x 109

42

44

46

48

50

52

54

56

58

60

f [Hz]|E

| [dB

uV]

Real-transient measurementGSM Incoming call

1.75 1.76 1.77 1.78 1.79 1.8 1.81 1.82 1.83 1.84 1.85

x 109

42

44

46

48

50

52

54

56

58

60

f [Hz]

|E| [d

BuV

]

-0.05 -0.04 -0.03 -0.02 -0.01 0 0.01 0.02 0.03 0.04 0.050

0.5

1

1.5

2

2.5

3

3.5

4x 10

-4

t [s]

|E| [

V/m

]

-4 -2 0 2 4 6 8

x 10-4

0

0.5

1

1.5

2

2.5

3

3.5

x 10-4

t [s]

|E| [

V/m

]

Time-domain 100 ms capture Time-domain 1,2 ms capture

48 dBuV/m

52 dBuV/m

1803 MHz

GSM channel

Electronics production plant measurement

Component insertion machines

Rolling line:

30 m x 5 m

Electronics production plant measurement

3 frequency bands were considered:

150 MHz433 MHz2,4 GHz

1.495 1.496 1.497 1.498 1.499 1.5 1.501 1.502 1.503 1.504 1.505

x 108

55

60

65

70

75

80

85

f [Hz]

|E| [d

BuV

/m]

Electronics production plant measurement

150 MHz band

Frequency measurement

1 minute MAX hold

step 1

-6 -4 -2 0 2 4 6

x 10-3

0

1

2

3

4

5

6

7

8x 10

-3

t [s]

|E| [V

/m]

Electronics production plant measurement

150 MHz bandTime

measurement 26 transients/minute

78 dBuV/m

step 2

4.325 4.326 4.327 4.328 4.329 4.33 4.331 4.332 4.333 4.334 4.335

x 108

45

50

55

60

65

70

75

80

f [Hz]

|E| [d

BuV

/m]

Electronics production plant measurement

433 MHz band

Frequency measurement

1 min MAX hold

step 1

-6 -4 -2 0 2 4 6

x 10-3

0

0.002

0.004

0.006

0.008

0.01

0.012

t [s]

|E| [V

/m]

Electronics production plant measurement

433 MHz bandTime

measurement 29 transients/minute

82 dBuV/m

step 2

2.3995 2.3997 2.3999 2.4001 2.4003 2.4005

x 109

17

18

19

20

21

22

23

24

f [Hz]

|E| [d

BuV

/m]

Electronics production plant measurement

2,4 GHz band

Frequency measurement

1 min MAX hold

step 1

-6 -4 -2 0 2 4 6

x 10-3

0

0.5

1

1.5

2

2.5

3x 10

-5

t [s]

|E| [V

/m]

Electronics production plant measurement

2,4 GHz band

Timemeasurement

30 dBuV/m

step 2

Measurement system

based on

external digitizing of

spectrum analyzer or

EMI receiver

IF output

Conclusions • Allows time-domain measurement of

signals

• Provide new uses to instruments already available in a typical EMC lab

• Can be used as a tool to study transient noise environments

High frequency

Non-periodic

Low level