LO emission or feedout: The emergence of
the LO signal from the input of a spectrum
analyzer. The level can be greater than 0
dBm on non-preselected spectrum analyzers
but is usually less than –70 dBm on preselected
analyzers.
LO feedthrough: The response on the display
when a spectrum analyzer is tuned to 0 Hz,
i.e., when the LO is tuned to the IF. The LO
feedthrough can be used as a 0-Hz marker,
and there is no frequency error.