Part of Electronics Troubleshooting & Design Review
EMI troubleshooting and EMC design review: find the source, correct the design, prepare for the accredited test
Micro Digital Engineering investigates interference and signal integrity problems in boards and power electronics: failed emission or immunity tests, noise that disturbs measurements, and unstable signals on critical interfaces. We locate the sources and coupling paths, correct the schematic and PCB, check the effect of the changes, and prepare the product for testing at an accredited EMC laboratory. Our work is engineering diagnosis and design correction; official EMC testing and certification are carried out by accredited laboratories.
Discuss the interference problem
Confidential task? We sign an NDA before you share technical files.
Can you investigate why our PCB fails EMC tests?
Yes. We start from the test report and the design: which frequencies exceed the limits, in which test and configuration. The layout, grounding, filtering, shielding and switching stages are then reviewed to find the likely sources and coupling paths, corrective changes are proposed, and their effect is checked before you return to the laboratory.
What the work covers
Locating interference sources and coupling paths
Switching stages, clocks, fast edges and cables are assessed as sources; the paths through grounding, layout, supplies and enclosure are traced from the test results and the design.
Analysis of switching and signals
Switching waveforms, ringing, edge rates, supply noise and the integrity of critical interfaces are measured and analysed on the real board.
Diagnostic measurements of interference
Conducted and radiated interference is investigated with the diagnostic methods suitable for the specific device, to compare the situation before and after a change. These measurements are not compliance results.
Design corrections
Changes to the schematic, PCB layout, filtering, grounding, shielding and cable connections, with the effect each change is expected to have.
Verification of the effect
Each change is checked under the same diagnostic set-up as before it, so its effect can be compared directly.
Preparation for the accredited test
Operating modes, test configuration and notes for the laboratory are prepared, and the design is reviewed against the requirements of the standards agreed for the product.
Engineering diagnosis, not certification
| Our engineering work | Accredited EMC laboratory | |
|---|---|---|
| Purpose | Find the causes, correct the design, compare before and after | Test the product formally to the standard |
| Measurements | Diagnostic measurements with calibrated equipment, compared before and after changes | Test set-up, methods and limits defined by the standard |
| Result | Analysis report, corrective changes, verification of their effect | Official test report |
Diagnostic measurements are made with calibrated measurement equipment. They show the effect of a change; whether the product complies is determined by the accredited test.
What’s included
Review of the test report, design review of layout, stack-up, grounding, filtering and shielding, analysis of power conversion stages as noise sources, signal integrity analysis of critical interfaces, diagnostic measurements, corrective design changes, verification of their effect and support for the repeat test.
What you receive
| Deliverable | Format | How it is checked |
|---|---|---|
| Analysis report | Document: likely sources, coupling paths, evidence | Review with you |
| Corrective changes | Change list: schematic, layout, filter components | Design review |
| Verification of changes | Document | Diagnostic comparison before and after the changes, under the same set-up |
| Preparation for repeat test | Notes for the laboratory: configuration, operating modes | Result of the accredited repeat test |
How the work runs
- The test report, the design and the product configuration are reviewed.
- Likely sources and coupling paths are identified and investigated on the board.
- Corrective changes are proposed and agreed.
- The changes are made on the boards or in a new revision.
- Their effect is checked with diagnostic measurements under the same set-up.
- The product and notes are prepared for the repeat test at the accredited laboratory.
See how we work.
How this differs from related services
| Service | Focus |
|---|---|
| EMI troubleshooting (this page) | Interference, emissions, immunity, signal integrity |
| Electronics troubleshooting | Any failure or unstable behaviour |
| Power electronics design | Design or redesign of the power stage itself |
| PCB design | A new board or board revision |
What to send us
- The EMC test report, if available.
- Schematics and PCB files.
- A description of the product, its power supply and cables.
- The standards the product must meet.
Common questions
Do you issue EMC certificates?
No. Certificates and official test reports are issued by accredited laboratories. Our work is the analysis and correction of the design.
Can you tell us whether the product will pass?
Not with certainty. Diagnostic measurements show whether a change reduces the interference; only the accredited test determines compliance with the standard.
Can interference come from the power converter?
Often. Switching stages are a common source, so the analysis includes them. See also power electronics design.
Do we need to change the whole board?
Not always. Some problems are solved with filtering, grounding or component changes; others need a layout revision. The analysis shows which.
Related services
- Electronics troubleshooting — general failure investigation.
- Power electronics design — redesign of power stages.
- PCB design — layout revisions.
Discuss the interference problem
Send the test report or describe the symptom, and the standards the product must meet.
Discuss the interference problem
Confidential task? We sign an NDA before you share technical files.