requirements for novel time-domain emi receivers

Requirements for novel

time-domain EMI receivers

Marc Pous

Grup de Compatibilitat Electromagnètica (GCEM), Universitat Politècnicade Catalunya (UPC)

[email protected]

EURAMET TC-EM SC-RF&MW meeting, 4-5 April 2017

Motivation: Novel Time-domain EMI receivers

Full compliant CISPR 16-1-1 ?

Oscilloscop

e+

Software


Full Time Domain EMI measurements system

IND60 European research project

Improved EMC test methods in industrial environments

Solve challenges at in-situ EMC measurements

Inherent uncontrolled environment conditions

Improve: uncertainty, precision, reliability, traceability,…

Standard laboratory Industrial environment

radiated and conducted EMI measurements

3


Frequency sweep instrumentation limitations

Based on superheterodyne receiver architecture

Suitable measuring non-varying interferences

Measurements carried out at different time

Frequency sweep

Omission of transient/discontinuous EMI

4


Problems of standard EMC measurements

5

Frequency sweep have limitations

Only capture repetitive

interferences (sweep synchronized)

Confuse broadband impulse noise

with narrow band interference

Solution: Increase meas time

Capture more undesired BGN at in-situ tests

Develop Method:Instantaneous capture,

compute the EMI spectrum

EUT


Full Time Domain EMI measurements system

Oscilloscope instantaneous capture

Obtain Full spectrum measurements with a

single measurement (bandwidth OSC)

FFT post-processing

Deal with time-variant, low repetition and

duration interferences

Reduced cost (Hardware and time) vs EMI Rx

6

Full compliant CISPR 16-1-1


Compliance with CISPR 16-1-1

Develop new Calibration Methodologies

5 10 15 20 25 30

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EM

I S

PE

CT

RU

M -

Voltage (

dB

µV

)

Frequency (MHz)

Pulse repetition of 100 Hz, CISPR Band B, CHA: PASS

Peakmean

= 66.2 dBuV

Peak/Quasi-Peak = 6.5 dB

Quasi-Peak/Average = 32.5 dB

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60

65

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EM

I S

PE

CT

RU

M -

Voltage (

dB

µV

)

Frequency (MHz)

Pulse repetition of 100 Hz, CISPR Band B, CHB: PASS

Peakmean

= 66.1 dBuV



5 10 15 20 25 30

25

30

35

40

45

50

55

60

65

70

EM

I S

PE

CT

RU

M -

Voltage (

dB

µV

)

Frequency (MHz)

Pulse repetition of 100 Hz, CISPR Band B, CHC: PASS

Peakmean

= 66.0 dBuV



5 10 15 20 25 30

25

30

35

40

45

50

55

60

65

70

EM

I S

PE

CT

RU

M -

Voltage (

dB

µV

)

Frequency (MHz)

Pulse repetition of 100 Hz, CISPR Band B, CHD: PASS

Peakmean

= 66.0 dBuV



5 10 15 20 25 301

1.2

1.4

1.6

1.8

2

VS

WR

Frequency (MHz)

VSWR 9 kHz.. 30 MHz, CHA: PASS

5 10 15 20 25 301

1.2

1.4

1.6

1.8

2

VS

WR

Frequency (MHz)

VSWR 9 kHz.. 30 MHz, CHB: PASS

5 10 15 20 25 301

1.2

1.4

1.6

1.8

2

VS

WR

Frequency (MHz)

VSWR 9 kHz.. 30 MHz, CHC: PASS

5 10 15 20 25 301

1.2

1.4

1.6

1.8

2

VS

WR

Frequency (MHz)

VSWR 9 kHz.. 30 MHz, CHD: PASS

20 40 60 80 100 120 140-2

-1

0

1

2

Frequency (kHz)

Am

plit

ude e

rror

(dB

)

Sine wave voltage accuracy, Band A, CHA: PASS

20 40 60 80 100 120 140

-10

-5

0

5

10

Frequency (kHz)

Fre

quency e

rror

(ppm

)

Sine wave frequency accuracy, Band A, CHA: PASS

20 40 60 80 100 120 140

100

200

300

400

Frequency (kHz)

RB

W (

Hz)

Selectivity, Band A, CHA: PASS

B20 dB

= 352.6 kHz

B6 dB

= 198.9 kHz

B1.5 dB

= 98.6 kHz

-0.15 -0.1 -0.05 0 0.05 0.1 0.15 0.2 0.250

10

20

30

40

Pro

babili

ty (

%)

Amplitude error (dB)

Distribution of the voltage error

-500 -400 -300 -200 -100 0 100 200 300 400 5000

20

40

60

80

Pro

babili

ty (

%)

Frequency error (ppm)

Distribution of the frequency error

195 196 197 198 199 200 201 2020

20

40

60

RBW (Hz)

Pro

babili

ty (

%)

Distribution of the error in the B6 selectivity

1. Sine wave voltage frequency (accuracy)

2. Sine wave frequency (accuracy).

3. Bandwidth (Overall selectivity).

4. Voltage standing wave ratio (VSWR).

5. Response to pulses

6. Weighting detectors

Specification for radio disturbance and immunity measuring apparatus and methods – Part 1-1: Radio disturbance and immunity measuring apparatus –

Measuring apparatus

CISPR requirementsFull TDEMI system

Hardware + softwareEvaluation procedure according to standard


• Voltage standing wave ratio (VSWR)

< 2 without attenuator & < 1.2 with attenuator

External 50 ohms

• Sine wave voltage accuracy

+-2 dB (relaxed-criteria)

• Random data generation: frequency & amplitude

Evaluate worst cases (Vertical scale, frequency step)

Amplitude Calibration

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1.2

1.4

1.6

1.8

2

VS

WR

Frequency (MHz)

VSWR 9 kHz.. 30 MHz, CHA: PASS

5 10 15 20 25 301

1.2

1.4

1.6

1.8

2

VS

WR

Frequency (MHz)

VSWR 9 kHz.. 30 MHz, CHB: PASS

5 10 15 20 25 301

1.2

1.4

1.6

1.8

2

VS

WR

Frequency (MHz)

VSWR 9 kHz.. 30 MHz, CHC: PASS

5 10 15 20 25 301

1.2

1.4

1.6

1.8

2

VS

WR

Frequency (MHz)

VSWR 9 kHz.. 30 MHz, CHD: PASS


Amplitude Calibration: Vertical scale

Example: 2 MHz tone -60 dBm 47 dBµV (0.224 mV)

Time domain instrumentation

Sample rate (processing gain)

Quantification (8, 10, 12, 16 bits)

Adjust properly vertical scale


Frequency accuracy and selectivity Calibration

• No intermediate frequency (IF)

Calibration parameters non-sense or different approach

IF overload

• Sine wave frequency (accuracy)

error < 0,5 fstep (1/4 RBW)

• Bandwidth (Overall selectivity)

Filter mask

10

Pseudo-Random data generation:

frequency & amplitude to find

worst cases


Evaluation of weighting detectors

• PK, AVG and QP detectors

Response to pulses, varying repetition rate

Level 66 dBµV +- 1.5 dB (flat pulse)

Generators unavailable at calibration labs

• Consider arbitrary generators

• Novel procedures developed (RFmicrowave

EMPIR project)

11

5 10 15 20 25 30

25

30

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40

45

50

55

60

65

70

EM

I S

PE

CT

RU

M -

Voltage (

dB

µV

)

Frequency (MHz)

Pulse repetition of 100 Hz, CISPR Band B, CHA: PASS

Peakmean

= 66.2 dBuV



5 10 15 20 25 30

25

30

35

40

45

50

55

60

65

70

EM

I S

PE

CT

RU

M -

Voltage (

dB

µV

)

Frequency (MHz)

Pulse repetition of 100 Hz, CISPR Band B, CHB: PASS

Peakmean

= 66.1 dBuV



5 10 15 20 25 30

25

30

35

40

45

50

55

60

65

70

EM

I S

PE

CT

RU

M -

Voltage (

dB

µV

)

Frequency (MHz)

Pulse repetition of 100 Hz, CISPR Band B, CHC: PASS

Peakmean

= 66.0 dBuV



5 10 15 20 25 30

25

30

35

40

45

50

55

60

65

70

EM

I S

PE

CT

RU

M -

Voltage (

dB

µV

)

Frequency (MHz)

Pulse repetition of 100 Hz, CISPR Band B, CHD: PASS

Peakmean

= 66.0 dBuV



For digital communication systems evaluation

weighting detectors are useless or limitedUnrelated with Bit Error Probability


APD detector

Why APD measurements?

APD Bit-Error-Probability (BEP)

QP detector was developed to protect analogue systems (Human perception). Not valid for nowadays DCS.

APD measurements limitations

Traditional frequency sweep methodologies are not suitable

Bandwidth available at the EMI receiver different from DCS

Definition & calibration insufficient at EMC standards

Freq < 1GHz?? QP not useful for DCS

Calibration pulses??

Time domain measurements??

-110 -105 -100 -95 -90 -85 -80 -75 -70 -65 -6010

-7

10-6

10-5

10-4

10-3

10-2

10-1

100

Power (dBm)P

rob

ab

ility

RxQUAL1

RxQUAL2

RxQUAL3

RxQUAL4

RxQUAL5

RxQUAL6

RxQUAL7

SLR interference

SHR interference

No interference

RXLevel


Vision

Employ arbitrary waveform generators emulating real interferences

With the aim to reproduce real disturbances

combining narrowband (sine wave) and broadband simultaneously

Pseudo-Random signals

Find worst cases

Unknown for manufacturers (avoid “Dieselgate”)

0 1 2 3 4 5

x 10-3

-1000

-500

0

500

1000

Time (s)

Voltage(m

V)

Channel A

Mathematicalrealistic EUT waveforms

ArbitraryWaveformGenerator

EMI Measurement

EMI receiver, oscilloscope

Software


Problematics to solve

Time domain singularities

vertical scale, freq. evaluation points, oversampling / memory

Objective: To be available to be calibrated at external laboratories

Nowadays Procedures/requirements based on superheterodyne receivers

Also consider Real Time Spectrum analysers based on FFT

Uncertainty budget shall vary according to frequency (not 1-2 dB flat)


And traditional receivers?

Push also frequency sweep to the limits (not only time domain)

Evaluate receiver and software employed

Prescan, etc to not miss interferences

Normative quite open and miss

disturbances

Transient interferences are problematic

Uncatchable EMI with freq. sweep

Critic for nowadays Digital

communication systems


Multichannel synchronous measurements

New capabilities for EMC

Measure mains impedance

Voltage/current synchronous measurement

In-situ

LISN not possible to install

EUT current not available test lab

Voltage limits

Z variation time

Objective: Reduce standard outdoors uncertainties from 15 dB due to unknown impedance to standard 2-4 dB


Ambient Noise Cancellation

17

ON

Time Domain measurement

system

EUT

Outdoors measurements

Validation of the ANC

Methodology to validate post-processing is performed accurately

EUT EMI not eliminated/attenuated

Opportunity for metrology institutes


Summary

Time domain measuring receivers CISPR16-1-1

Need novel calibration procedures employing realistic disturbances

Substitute weighting detectors by probabilistic ones

Quasi peak APD Need more clarifying requirements

Multichannel possibilities

Include procedures like ANC at the standards

Main impedance characterization

Create Intermediate EMC test facilities

Demand for industry Railway, Photovoltaic, etc… PRT proposal

requirements for novel time-domain emi receivers

Documents