Setting Shift LO (Reducing Unnecessary Image Response)

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 E5080A 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.

Note: This function is not available for frequencies below 150 MHz (E5080A), 400 MHz (M9485A).

Turning ON Shift LO Mode

  1. Press Sweep > Source Control > Shift LO.

  2. Input the maximum frequency.

  3. Click the switch of the softkey to turn on the Shift LO function.

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, ā€œCā€ is changed to "CĪ”" 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.