Monolithic Power Systems, Inc. · NASDAQ:MPWR
Monolithic Power Systems — Rohde & Schwarz — Technical Presentation (November 2021)
38 slides from Monolithic Power Systems's technical presentation, Nov 16, 2021
Slide 1: Efficient Usage of Measurement Equipment for EMC Analysis
EFFICIENT USAGE OF MEASUREMENT EQUIPMENT FOR EMC ANALYSIS Alexander Küllmer – Application Engineer Oscilloscopes
Slide 2: Agenda
AGENDA ► EMI Receivers vs. Spectrum Analyzers Full vs. Pre-compliance Preselection RBW Filter Detectors Stepped/sweeped vs time-domain scan ► Oscilloscope Comparison of measurement results 2 Rohde & Schwarz 11/16/2021 Efficient Usage of Measurement Equipment for EMC Analysis
Slide 3: EMI Receiver vs. Spectrum Analyzer
EMI RECEIVER VS. SPECTRUM ANALYZER ► Block diagram ► Preselector ► RBW ► Detector
Slide 4: Differences Between Analyzer and EMI Receiver
DIFFERENCES BETWEEN ANALYZER AND EMI RECEIVER Pulse limiter Input 2 EMI Receiver variable Preselection ATT + Highest Dynamic range Attenuator + Robust against pulses Input 1 + CISPR/EN conform - Low analysis bandwidth Preamp. Rej. Wideband Digital Lowpass Mixer IF-Gain Filter IF Processing Display S
Slide 5: Preselector – Principle
PRESELECTOR – PRINCIPLE u RF Bandwidth Preselection Mixer level Measurement bandwidth Dynamic range p-pls-1 f 5 Rohde & Schwarz 11/16/2021 Efficient Usage of Measurement Equipment for EMC Analysis
Slide 6: Preselector – Realization
PRESELECTOR – REALIZATION ► What is a preselector? Filter bank Filters are switched automatically based on frequency Filter bandwidths are wide enough to not reduce the desired frequency range ► Purpose of the preselector? Higher dynamic range Example: R&S ESW 6 Rohde & Schwarz 11/16/2021 Ef
Slide 7: Preselector – Calculation
PRESELECTOR – CALCULATION Dynamic range Without preselection 𝐵𝑅𝐹 𝐿𝑚𝑎𝑥 − 20 ∙ log 𝑑𝐵 𝐵𝐼𝐹 With preselection 𝐵𝑃𝑅𝐸 𝐿𝑚𝑎𝑥 − 20 ∙ log [𝑑𝐵] 𝐵𝐼𝐹 𝐿𝑚𝑎𝑥 : Maximum input level 𝐵𝑅𝐹 : Bandwidth of RF input signal 7 Rohde & Schwarz 11/16/2021 Efficient Usage of Measurement Equipment…
Slide 8: RBW Filter Shape within EMI Receivers and Spectrum Analyzer
RBW FILTER SHAPE WITHIN THE EMI RECEIVERS AND SPECTRUM ANALYZER EMI Receiver ► Gauss filter ► 6 dB definition ► CISPR 16-1-1: 200 Hz, 9 kHz, 120 kHz, 1 MHz ► MIL-STD-461: 10, 100 Hz, 1, 10, 100 KHz, 1 MHz Spectrum analyzer ► Support of different filters ► 3 dB definition ► Bandwidths: 1/2/3/5 sequen
Slide 9: Filter Shape EMI Receiver / Analyzer
FILTER SHAPE EMI RECEIVER / ANALYZER Spectrum analyzer 1kHz EMI receiver 9 Rohde & Schwarz 11/16/2021 Efficient Usage of Measurement Equipment for EMC Analysis
Slide 10: Realization of RBW Filter
REALIZATION OF RBW FILTER IQ-Demod Digital RBW Filter Q filter coefficients From 90° 𝐼 2 + 𝑄2 VIF ADC I filter coefficients LO-Demod (NCO) 10 Rohde & Schwarz 11/16/2021 Efficient Usage of Measurement Equipment for EMC Analysis
Slide 11: Detectors within EMI Receivers and Spectrum Analyzer
DETECTORS WITHIN EMI RECEIVERS AND SPECTRUM ANALYZER ► Peak detector: EMI Receiver Display the max value within its detector time ► Quasipeak detector: Display the weighted value within its detector time (typical >= 1s time) Spectrum analyzer ► Average detector: Display the avg value within its dete
Slide 12: Detectors within EMI Receivers and Spectrum Analyzer
DETECTORS WITHIN EMI RECEIVERS AND SPECTRUM ANALYZER EMI Receiver Spectrum analyzer 12 Rohde & Schwarz 11/16/2021 Efficient Usage of Measurement Equipment for EMC Analysis
Slide 13: Different Sweep Modes
DIFFERENT SWEEP MODES ► Stepped mode: EMI Receiver Available at receiver and spectrum analyzer Stepped through the spectrum in discreet steps Measurement time (tmeas) will be directly set ► Swept mode: Spectrum analysator Available at spectrum analyzer Sweep through the f spectrum continu
Slide 14: Improving Sweep Time: Time Domain Scan
IMPROVING SWEEP TIME: TIME DOMAIN SCAN 1 2 ► Frequency domain ► Time domain Signal spitted into sequential Sampling of windowed parts in time domain frequency parts T1 T2 T3 T4 … 3 4 F(s) f(t) ► Time to Frequency ► Frequency range FFT of the time based signal into Combination of spectra frequency ra
Slide 15: Time Domain Scan
TIME DOMAIN SCAN ► Speed improvement Degree of improvement depends on detector type, dwell time, and measurement bandwidth ► Higher probability of intercept for short duration (intermittent / pulsed) signals Higher confidence that signals with low repetition rates are not being missed 15 Rohde &
Slide 16: Measuring Fast and Reproducible
MEASURING FAST AND REPRODUCIBLE • Peak detectors used for a broad frequency sweep • Limit lines set according to standard • At frequency points beyond limit lines, quasi-peak detector measurement is used 16 Rohde & Schwarz 11/16/2021 Efficient Usage of Measurement Equipment for EMC Analysis
Slide 17: Test Automation
TEST AUTOMATION Semi / fully automatic EMI test sequences • Fast preview measurement – PK or PK/AVG detection – TD scan or stepped frequency • Data reduction – Evaluation of the critical frequencies for final measurement • Final measurement – Quasipeak or Quasipeak/CAV detection – Measurement on a f
Slide 18: Performing In Depth Signal Analysis
PERFORMING IN DEPTH SIGNAL ANALYSIS ► Logarithmic frequency sweep – analyze lower frequencies in more detail ► AM and FM demodulation with audio output ► IF analysis ► Zero span ► Real-time function (persistence mode, spectrogram, frequency mask trigger) ► (Scan) Spectrogram 18 Rohde & Schwarz 11/16
Slide 19: Time Domain Scan Spectrogram
TIME DOMAIN SCAN SPECTROGRAM Spectrogram in receiver mode Spectrogram in split screen mode can be combined with: • Time Domain scan • Stepped frequency scan • IF analysis • Bargraph on/off 19 Rohde & Schwarz 11/16/2021 Efficient Usage of Measurement Equipment for EMC Analysis
Slide 20: Example: Scan Spectrogram
PERFORMING IN DEPTH SIGNAL ANALYSIS EXAMPLE: SCAN SPECTROGRAM ► Pressing the horn of a car: 3 short, 1 long 20 Rohde & Schwarz 11/16/2021 Efficient Usage of Measurement Equipment for EMC Analysis
Slide 21: Oscilloscope
OSCILLOSCOPE ► Block diagram ► Time domain to frequency domain
Slide 22: Block Diagram
BLOCK DIAGRAM 22 Rohde & Schwarz 11/16/2021 Efficient Usage of Measurement Equipment for EMC Analysis
Slide 23: Oscilloscope for EMI Measurements / Debugging
OSCILLOSCOPE FOR EMI MEASUREMENTS / DEBUGGING EMI Receiver Oscilloscope ► Frequency domain ► Time domain ► Preselector and RBW available ► No Preselector and no IF Narrowband measurements Broadband measurements ► Not compliant to EMI standards 23 Rohde & Schwarz 11/16/2021 Efficient Usage of Mea
Slide 24: Oscilloscope for EMI Debugging: Typical Objections
OSCILLOSCOPE FOR EMI DEBUGGING TYPICAL OBJECTIONS ► … is the scope sensitive enough? Yes: 1mV/Div gives DANL of ~0 dBµV = -107 dBm (@500 MHz, 120 kHz RBW, 50 W) ► … what about a (6 dB) EMI filter? Not necessary for EMI debugging ► … what about limit lines? The mask tool includes limit line fun
Slide 25: Oscilloscope for EMI Debugging: Traditional FFT Approach
OSCILLOSCOPE FOR EMI DEBUGGING TRADITIONAL FFT APPROACH Time Domain Frequency SW Domain t Windowing FFT Zoom Record length (f1…f2) f f1 f2 Data acquisition Display 1. The FFT calculation will produce a frequency domain result from 0 Hz to max Freq. 2. Optionally Windowing is applied before the FFT c
Slide 26: Oscilloscope for EMI Debugging: FFT Implementation at R&S
OSCILLOSCOPE FOR EMI DEBUGGING FFT IMPLEMENTATION AT R&S ► Spectrum Analyzer Use Model Frequency domain controls time domain: Record length and sampling rate are updated automatically ► FFT for maximum performance Frequency zoom before FFT: e.g. 500 MHz center / 10 MHz span: 20 MS/s instead of 1
Slide 27: Oscilloscope for EMI Debugging: Multiple & Overlapping FFT
OSCILLOSCOPE FOR EMI DEBUGGING MULTIPLE & OVERLAPPING FFT ı Faster processing & faster display update rate ı Ideal for finding sporadic signal details ı Get a deeper look how the spectral energy is spread within a single acquisition. single acquisition FFT 1 FFT 2 FFT 3 FFT 4 FFT 1 FFT 2 FFT 3 50% o
Slide 28: Oscilloscope for EMI Debugging
OSCILLOSCOPE FOR EMI DEBUGGING Max hold, AVG and RMS Spectrum units Correction factor for a LISN Multiple FFTs Record Length < 1MS Green: Max-Hold Purple: Current spectrum, intensity graded *Note: Envelope = Max Hold 28 Rohde & Schwarz 11/16/2021 Efficient Usage of Measurement Equipment for EMC Anal
Slide 29: Oscilloscope for EMI Debugging
OSCILLOSCOPE FOR EMI DEBUGGING 29 Rohde & Schwarz 11/16/2021 Efficient Usage of Measurement Equipment for EMC Analysis
Slide 30: EMI Debugging Workflow
EMI DEBUGGING WORKFLOW Activate FFT Adjust Filter Bandwidth Adjust Frequency Range / Activate Peak list in the Use Zoom Window measurement menu Signal with RBW 100 kHz Signal with RBW 1 kHz 30 Rohde & Schwarz 11/16/2021 Efficient Usage of Measurement Equipment for EMC Analysis
Slide 31: Comparison Measurement Results
COMPARISON MEASUREMENT RESULTS ► What Signal was analyzed? Signalgenerator: R&S SMBV100B Signaltype: 2 Carriers with 100 kHz Spacing Center frequency: 1 GHz Attenuation between the 2 carriers: 60 dB Power splitter provided same signal to EMI Receiver and Oscilloscope 31 Rohde & Schwarz 11/
Slide 32: Comparison Measurement Results
COMPARISON MEASUREMENT RESULTS EMI Receiver Oscilloscope 32 Rohde & Schwarz 11/16/2021 Efficient Usage of Measurement Equipment for EMC Analysis
Slide 33: Comparison Measurement Results
COMPARISON MEASUREMENT RESULTS EMI Receiver Oscilloscope Better SNR Clear differentiation between noise floor and signal components possible 33 Rohde & Schwarz 11/16/2021 Efficient Usage of Measurement Equipment for EMC Analysis
Slide 34: Comparison Measurement Results
COMPARISON MEASUREMENT RESULTS EMI Receiver Oscilloscope Wideband Phase Noise Smallband signal filters 34 Rohde & Schwarz 11/16/2021 Efficient Usage of Measurement Equipment for EMC Analysis
Slide 35: When to Use Which Instrument? From Compliance to EMI Debugging
WHEN TO USE WHICH INSTRUMENT? FROM COMPLIANCE TO EMI DEBUGGING EMI Receiver Spectrum-/ Signalanalyzer Oscilloscope ► 6 dB Filters ► 3 dB Filters ► 3 dB Filter ► Preselector avialable ► High selectivity ► One shot analysis of whole ► Highest selectivity ► High sensitivity frequency range ► CISPR comp
Slide 36: When to Use Which Instrument? From Compliance to EMI Debugging
WHEN TO USE WHICH INSTRUMENT? FROM COMPLIANCE TO EMI DEBUGGING EMI Receiver Spectrum-/ Signalanalyzer Oscilloscope ► 6 dB Filters ► 3 dB Filters ► 3 dB Filter ► Preselector avialable ► High selectivity ► One shot analysis of whole ► Highest selectivity ► High sensitivity frequency range ► CISPR comp
Slide 37: Instrument Positioning
INSTRUMENT POSITIONING COMPLIANCE PRE-COMPLIANCE DEBUGGING EMI Compliance Test Receiver Oscilloscope EMI Precompliance Receiver Value spectrum Spectrum Analyzer with EMI Application analyzer 37 Rohde & Schwarz 11/16/2021 Efficient Usage of Measurement Equipment for EMC Analysis
Slide 38: Questions
QUESTIONS [email protected] Subject: „EMC Workshop 2021 “ 38 Rohde & Schwarz 11/16/2021 Efficient Usage of Measurement Equipment for EMC Analysis
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