FAQs from Rohde & Schwarz

Correct Step Size for a Stepped EMI Scan?

Question

Why is it important to use the correct step size for a stepped EMI scan?

Answer

In the case of EMI measurements, the frequency range is analyzed in frequency steps. An important parameter is the IF bandwidth specified by the standards. The step size for a scan depends on the IF range.

The step size is important for the following reasons:

- If the step size is very large, narrowband interferer cannot be detected.

- If the step size is somewhat too large, additional measuring errors are caused

(measurement values are too small).

We therefore recommend the following value: step size < 0.5 * IF bandwidth.