While the terms used are common, the below may serve as a way of clarifying the nomenclature to be used in this chapter.
Frequency/Power Plan
This is a description of the frequencies involved in the mixer measurement including the input sweep range (if swept), the LO sweep range (if any), and how the output frequency is related to the input frequency. It also includes the power levels required. In the case of a power sweep, the fixed frequencies are part of the plan along with which variable is sweeping in power (input or LO) and over what range.
Input Match, Output Match, and LO Match
These are the usual return loss terms. The terms ‘input’ and ‘output’ are used in the dialog choices in lieu of IF and RF to avoid some confusion. The default has an input of RF and an output of IF but these can be reversed. The arrow directions in the diagram always make clear what the input port is. A standard S-parameter calibration (1-port or more, but with different frequency ranges on the different ports) is used.
Isolation
This is transmission through the mixer (input->output, output->input, LO->output or LO->input) but without frequency conversion. The test frequency range is based on the stimulus port of the selection and the defined frequency plan. This is sometimes also called ‘bleed through’. A normalization or a standard s-parameter calibration is normally used.
Conversion Gain/Loss
This is a measure of energy transferred from the input frequency to the output frequency. There are a number of different calibrations available ranging from a simple scalar (but narrowband) normalized power measurement to enhanced match correction that vectorially takes into account the DUT’s match (input and output) interacting with the VNA. The NxN technique discussed in the next chapter is another method for getting at conversion gain/loss vectorially.