Setting Shift LO (Reducing Unnecessary Image Response)

• Overview

• Turning ON Shift LO Mode

Other topics about Optimizing Measurements

Overview

The Shift LO mode is used to set the local signal (LO).Generally, the VNA sets the local signal (LO) as RF+IF. However, this causes image response at certain frequencies. To reduce the unnecessary image response, the LO mode allows you to select the local signal (LO). This function is available on the M980xA, M983xA, P50xxA/B and M9485A.

Shift LO mode should be turned ON for frequencies below the center frequency of the bandpass filter and turned OFF for frequencies above the centre frequency of the bandpass filter.

• Shift LO mode ON: LO = RF-IF

• Shift LO mode OFF: LO = RF+IF

Note: This function is not available for frequencies below 322.375 MHz (M98xxA, P50xxA/B).

Note: System calibration (adjustment) is not taken into account when Shift LO mode is ON. Calibration should be performed before your measurement. If this function is turned ON after a calibration, “C” is changed to "CΔ" on the status bar.

Note: When List Shift LO in Segment Sweep is OFF, the setting of global setting (Sweep > Source Control > Shift LO) is used.

Max Frequency

Sets the maximum frequency for the measurement sweep. By default, the maximum frequency is set to the maximum frequency of the unit.

Note: This setting is only valid when the Shift LO mode is turned ON.