Electromagnetic Interference (EMI) occurs when unwanted electrical signals affect the operation of circuits and electronic systems. It can cause communication failures, instabilities, data loss, and even permanent damage.
In the context of industrial production and testing, understanding and controlling EMI is essential to ensure reliability, safety, and compliance with regulatory standards.
📡 Where does EMI come from?
EMI can be:
1. Conductive – Comes through wires and traces:
- Switched power supplies
- Motors, relays, and coils
- Improperly sized GND or ground noise
2. Radiated – Comes through the air:
- Unshielded RF emission
- Long cables without proper termination
- Coupling between nearby circuits
⚙️ Effects of EMI in testing and production
- False negatives in functional tests
- Intermittent communication failures (UART, LVDS, CAN, I2C…)
- Oscillations in analog measurements
- Abnormal performance in sensors or actuators
- Failure in compliance tests (e.g., CE, FCC, Anatel)
🛠️ How AJOLLY Testing addresses EMI in test environments
AJOLLY Testing applies good design and engineering practices to reduce and isolate electromagnetic interference:
During design:
- Shielded cables and proper grounding
- Use of EMI filters and separation of digital/analog signals
- Fixtures with grounded metal casing
- Separation of power and signal GNDs
In test software:
- Programmed delay for signal stabilization
- Reading with statistical averaging to reduce noise
- Checks for intermittent failures with repeated reading
In instrumentation:
- Equipment with high immunity (PXI, DAQ isolated)
- Differential probes for critical measurements
- Continuous monitoring with alerts for out-of-standard noise
✅ Diagnosis and validation focused on EMI
AJOLLY also supports testing with:
- EMI shielding chambers for RF DUTs (shield box)
- Simulations of conducted/radiated noise
- Support for CE/FCC pre-certification
- Robustness evaluation against disturbances
Controlling EMI is not just a technical requirement — it is an essential step to ensure quality, reliability, and regulatory compliance.