The Simplest Demo With the Most Direct Compliance Consequence
At the Rohde & Schwarz booth at the EMC exhibition in Cologne this January, one setup stood out for being the opposite of complex.
No robot arm. No radar target simulator. No floor-to-ceiling instrument rack with seven layers of hardware.
Just three things on a white bench: a LISN, a light bulb, and an EMI test receiver. Connected in series. Running a live conducted emissions measurement from 9 kHz to 30 MHz.
The banner above read: CONDUCTED AND RADIATED EMISSIONS TESTING.
This is the test that every electrical product sold in Europe must pass before it can carry the CE mark. It is also the test that most product development teams encounter first when they start thinking about compliance — and the one where the gap between "looks fine on the bench" and "passes the formal test" is most frequently discovered late and expensively.
Rohde Schwarz conducted and radiated emissions testing booth with ENV216 LISN globe lamp DUT EPL1 EMI test receiver and ELEKTRA software at EMC exhibition Cologne Germany 2026
The Three Elements and Why Each One Is Necessary
The conducted emissions test chain has been standardized for decades. The three elements on the R&S bench represent that chain in its canonical form — but each one is more technically specific than it appears.
The LISN: R&S ENV216 Two-Line V-Network
The R&S ENV216 is a two-line V-Network (Voltage Network) LISN — the standardized 50 Ω / 50 µH + 5 Ω impedance network specified by CISPR 16-1-2 for conducted emissions testing on AC power lines. The front panel labels confirm the configuration: EQUIPMENT UNDER TEST (the blue CEE Schuko socket, rated max. 16 A), ARTIFICIAL MAINS input, and RF OUTPUT to the measurement instrument.
The LISN serves three simultaneous functions that are easily underestimated:
→ It defines the measurement impedance — the 50 µH + 5 Ω network presents a standardized 50 Ω impedance to the DUT's power input across the CISPR frequency range (150 kHz – 30 MHz for conducted). Without this defined impedance, the "conducted emissions" measurement would depend on the impedance of whatever power source happens to be on the bench — which varies between labs, between countries, and between test sessions. Results would be incomparable.
→ It isolates the measurement from the mains supply — the inductor in the LISN blocks RF interference from the mains from entering the measurement, ensuring that what the receiver measures is emissions from the DUT, not noise from the building's electrical infrastructure.
→ It provides the standardized RF output port — the 50 Ω BNC connector on the RF OUTPUT that connects directly to the EMI receiver's input, with calibrated insertion loss that can be corrected in the measurement results.
The globe-shaped LED lamp plugged into the EUT socket — clearly illuminated during the demo — is the device under test. As covered in Article 022 and Article 025, a modern LED lamp contains a switch-mode LED driver that generates switching harmonics from the 150 kHz CISPR start frequency through the MHz range. It is a textbook conducted emissions source: small, common, and electromagnetically non-trivial.
The R&S EPL1: EMI Test Receiver 9 kHz – 30 MHz
The R&S EPL EMI Test Receiver connected to the LISN's RF output is covering 9 kHz to 30 MHz — the conducted emissions measurement range that spans from the start of CISPR Band A (9 kHz) through the top of the conducted emissions range (30 MHz), above which the radiated emissions measurement takes over.
The screen display during the demo shows the complete measurement in progress:
→ Frequency axis: 9 kHz – 30 MHz — the full conducted emissions range in one sweep
→ Vertical axis: dBµV — the standard unit for conducted emissions, decibels relative to 1 microvolt at the LISN's 50 Ω output
→ Green trace: Max Peak detector — the fastest scan, capturing the envelope of all emission peaks across the frequency range
→ Red/orange limit lines — the CISPR Class B limits for conducted emissions. Emissions above these lines represent a compliance failure.
→ Trace annotation: QP Max + 2CA Max — indicating that quasi-peak and average detector results are also being tracked, the two detector types that CISPR standards primarily specify for compliance determination
The current frequency marker reading 9.0000 kHz indicates the scan has just started at the lower end of the measurement range — the receiver is working upward through the spectrum.
What the display reveals about the LED lamp's emission profile is the practical demonstration value of this setup: the green spectral trace shows emission peaks at specific frequencies corresponding to the lamp's LED driver switching frequency and its harmonics. Each peak that approaches or exceeds the red limit line is a potential compliance issue. The quasi-peak detector — which weights brief high-amplitude events less severely than sustained ones — is the primary compliance criterion, which is why the QP result is tracked alongside the Max Peak.
The R&S EPL1000 Series: Pre-Compliance to Full Compliance
The center screen above the demo bench was showing the product card for the R&S® EPL1000 series — a 3D rendering of three instrument variants (EPL1000, EPL1001) with the tagline: "Also EMI test receiver for pre-compliance and compliance environments."
The word "also" in that description is doing significant work. The EPL series is positioned primarily as a portable spectrum analyzer and signal analyzer — but the EMI test receiver functionality is built in as a first-class feature, not an afterthought option. This means the same physical instrument can serve:
→ Pre-compliance work on the development bench — an engineer running quick conducted emissions checks after each hardware revision, using the EPL as a portable bench instrument without needing to book a formal test lab
→ Final compliance measurement in a certified test lab — with the CISPR 16-compliant detector implementations, calibration traceability, and measurement uncertainty documentation required for a legally valid test report
This dual positioning reflects a real shift in how EMC compliance is being integrated into product development workflows. The traditional model — informal bench checks with a spectrum analyzer throughout development, formal EMI receiver test only at the compliance stage — creates a discontinuity: the pre-compliance results don't predict the formal results reliably because the detector implementations and measurement parameters differ between the two instruments.
An instrument like the EPL1000 that implements full CISPR-compliant detector behavior in a portable form factor closes that gap. The pre-compliance measurement and the compliance measurement are made with the same detectors, the same measurement bandwidths, and the same frequency stepping — so a passing pre-compliance result is a reliable predictor of a passing formal result.
R&S ELEKTRA: The Software Layer That Ties It Together
The left screen above the bench was showing the R&S ELEKTRA EMC test software — the same software platform visible across multiple R&S demos at this exhibition. In the conducted emissions context, ELEKTRA handles:
→ Test configuration — selecting the applicable standard (CISPR 32 Class B, EN 55014, CISPR 25, etc.), the frequency range, and the detector requirements
→ Instrument control — driving the EPL receiver through the measurement sequence, applying calibration corrections, and managing the LISN switching if the test requires measuring both Line and Neutral separately
→ Limit line management — loading the correct limit table for the applicable standard and comparing measured values in real time
→ Report generation — producing the structured test report with instrument settings, calibration data, measurement results, and pass/fail determination in the format required for compliance documentation
For a test lab running conducted emissions measurements on multiple products per day, the ELEKTRA automation layer is what makes the workflow repeatable and the results comparable across different operators, different days, and different batches of the same product.
Why This Is the Most Important Test in the R&S Cologne Lineup
Across the R&S demos at the Cologne exhibition — 44 GHz compliance with robot arm positioning (Article 027), automotive radar testing under EMC conditions (Article 028), EMC testing of wireless DUTs (Article 029) — the conducted emissions demo stands out for a different reason.
The other demos represent specialized, high-value test scenarios relevant to specific industries: automotive radar, wireless product certification, millimeter-wave compliance. Important markets, but narrow ones.
Conducted emissions testing from 9 kHz to 30 MHz via a LISN applies to every electrical product sold in Europe. Every power supply. Every motor. Every LED driver. Every industrial controller. Every consumer appliance. The market for this test capability is not a specialized vertical — it is the entire electrical products industry.
The LISN + EPL receiver + ELEKTRA combination shown at this booth is the entry point to that market: a compact, portable, full-compliance-capable conducted emissions measurement system that can be deployed on a development bench, in a pre-compliance lab, or in a certified test facility with the same instrument, the same software, and the same results.
The globe lamp glowing on the LISN was not a simplified stand-in for a more complex DUT. It was the honest representation of what most conducted emissions testing actually looks like: a real consumer product, plugged into a standardized impedance network, generating switching noise that has to stay below a limit line for the product to be sold legally. The test has not changed in its essentials for decades. The instrumentation has gotten significantly better at making it fast, repeatable, and traceable.
Instruments observed: Rohde & Schwarz ENV216 Two-Line V-Network LISN · R&S EPL EMI Test Receiver 9 kHz – 30 MHz · R&S EPL1000 Series · R&S ELEKTRA EMC test software · conducted emissions test chain with LED globe lamp as DUT
All photos: Thomas · @SignalByThomas