Vector Mixer Calibration

Vector scalar calibration is a calibration method applied for mixer measurements. This method allows measurement of both reflection and transmission S-parameters in vector form, including phase and group delay of transmission coefficient.

The vector mixer measurements require an additional mixer with filter, which is called calibration mixer.

The filter separates the IF, which is the input frequency for the mixer under test:

RF + LO
RF – LO
LO – RF

Both calibration mixer and mixer under test are powered from one LO.

The vector mixer measurement is a combination of a 2-port calibration and a de-embedding function (See Figure 63).

Figure 63 Vector mixer measurements

The de-embedding function requires an S-parameter file of the circuit. Acquisition of such a file for the calibration mixer/filter pair is called vector mixer calibration.

To obtain an S-parameter file of the calibration mixer/filter, you need to use SHORT, OPEN, and LOAD calibration standards (See Figure 64).

Figure 64 Vector Mixer Calibration

Vector Mixer Calibration Procedure

Before you start the calibration, perform the following settings: activate a channel and set its parameters (frequency span, IF bandwidth, etc.), and define the calibration kit.

Perform 2-port calibration.
Assemble vector calibration setup.
Set frequency and power of the external LO.

		To access the vector mixer calibration menu, use the following softkeys:
		To select the number of test port connected to the calibration mixer, click Select Port.
		Enter the LO frequency, using LO Frequency softkey.
		Select the frequency to be separated by the filter, using IF Frequency softkey:
		Connect SHORT, OPEN and LOAD standards to IF filter output as shown in Figure 64. Perform the measurement using the respective standard softkey.
		To complete the calibration procedure, click Save To Touchstone File.
Note		You can check the calibration status in channel status bar (See Table 20) – F2 and Dmb labels (2-port calibration and de-embedding function).