EMI Debugging with Oscilloscopes
Application Note Overview
To some extent, all electric as well as electronic devices emit unwanted electromagnetic fields and transmit unwanted disturbance voltages and currents via their connection lines. In order to prevent such electromagnetic interference affecting the operation or radio reception of other devices, legal limits for emissions are stipulated by law in every economic region.
EMC conformity tests are used to verify compliance with required limits. Timeconsuming debugging is typically required in case of noncompliance. Prompt analysis of EMI problems starting in development is a key success factor for products that need to be launched onto the market in due time.
The powerful FFT function of the R&S®RTO6 and R&S®RTP digital oscilloscopes from Rohde & Schwarz allows analysis of EMI problems right at the developer's own workplace. With their 0.1 mV/div sensitivity, up to 6 GHz bandwidth and very low input noise, these oscilloscopes are a very useful tool in this application. Developers can use near-field probes as well as current probes to localize and analyze unwanted radiated emissions and disturbance currents and develop efficient solutions to reduce them.
This application note provides a simple guideline to help hardware developers analyze EMI problems using near-field probes in conjunction with digital oscilloscopes. The actual analysis process is demonstrated based on a practical example using the R&S®RTO6.