Frequency converters e.g. in satellite transponders need to be characterized not only in terms of amplitude transmission but also in terms of phase transmission or group delay, especially with the transition to digital modulation schemes. They often do not provide access to the internal local oscillators.
This application note describes a method using the R&S® ZNA analyzer family to measure group delay of mixers and frequency converters with an embedded local oscillator very accurately. Download the full document to learn more.