comparison of time domain scans and stepped frequency scans in emi test receivers -九游官网下载

taking the r&s esr emi test receiver as an example, this paper looks at a cispr 16-1-1- compliant test instrument with time domain scanning capabilities. the paper compares the measurement speed and level measurement accuracy of a conventional stepped frequency scan versus an advanced fft-based time domain scan. it also contains guidance on making optimum use of time domain scans.

table of contents

1 motivation ................................................................. 3

2 how an fft-based test receiver operates ........... 4

2.1 a classic test receiver ........................................ 4

2.2 a test receiver with digital signal processing ..... 4

2.3 the window function ............................................ 6

2.4 overlapping in the time domain ........................... 8

2.5 overlapping in the frequency domain .................. 9

2.6 detectors ...............................................................10

3 performance comparison .........................................11

3.1 comparison of level measurement accuracy .......11

3.1.1 cispr band c, peak detector ...........................11

3.1.2 cispr band c, quasi-peak detector ................13

3.1.3 cispr band b, quasi-peak detector..................14

3.2 comparison of measurement speeds ...................16

4 choosing the right measurement time .................. 17

5 summary ................................................................. 23