Mixer Parameters That You Can Measure - HP 8753E User Manual

Mixer Parameters That You Can Measure

and RF feedthru.
Reflection characteristics include return loss, SWR and complex impedance.
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Characteristics of the signal at the output port include the output power, the spurious or
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harmonic content of the signal, and intermodulation distortion.
Other parameters of concern are isolation terms, including LC to RF isolation and Lo to IF
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isolation.
Accuracy Considerations
In mixer transmission measurements, you have RF and LO inputs and an IF output. Also
emanating from the IF port are several other mlxing products of the RF and LO signals. In
mixer reflection measurements, leakage signals from one mixer port propagate and appear
at the other two mixer ports. These unwanted mixing products or leakage signals can cause
distortion by mixing with a harmonic of the analyzer's llrst down-conversion stage. 'lb ensure
that measurement accuracy is not degraded, you must filter certain frequencies or avoid them
by frequency selection. If you place attenuators at all mixer ports, you can reduce mismatch
uncertainties.
6-168 Application and Operation Concepts
Figure 6-88. Mixer hrameters