LO:Downconverter Center Frequency

Enables in-band retuning and specifies the current frequency of the RF downconverter. This value is expressed in Hz.

After you set this property, the RF downconverter is locked to that frequency until the value is changed or the property is reset. Locking the downconverter to a fixed value allows frequencies within the instantaneous bandwidth of the downconverter to be measured without the overhead of retuning the LO and waiting for the LO to settle. This method is called in-band retuning and it has the highest benefit on analyzers that have larger LO settling times. After setting the downconverter center frequency, you can set the center frequency to the frequencies at which you want to take the measurements.

If you want to avoid the LO leakage or DC offset of analyzers that use a direct conversion architecture, it is more convenient to use the Downconverter Frequency Offset or LO Leakage Avoidance Enabled properties.

If you set this property, any measurements outside the instantaneous bandwidth of the device are invalid. To disable in-band retuning, reset this property or call the RFmxInstr Reset to Default VI.

You do not need to use a selector string if you want to configure this property for all signal instances. Specify the signal name in the selector string if you want to configure or read that signal instance. Refer to the Selector Strings topic for information about the string syntax.

The default value is the carrier frequency or spectrum center frequency.

Supported devices: PXIe-5644/5645/5646, PXIe-5663/5663E/5665/5668, PXIe-5820/5830/5831/5832/5840/5841/5842

Remarks

The following table lists the characteristics of this property.

Short Name	Downconverter Freq
Data type
Permissions	Read/Write
High-level VIs	N/A
Resettable	Yes