NI Tuner


Function Prototype

niTuner_setFreq (int taskID, double desiredRFFrequency, double span, double *actualIFFrequency, double *actualRFTunedFrequency, double *freqShift);


This function sets a single frequency in the scan list with a specified span and triggers the PXI-5600 downconverter to settle on that frequency.

Note  If new center frequencies of less than 15 MHz are specified after a call to this function, attenuation is automatically adjusted. This may add an additional 20 dB attenuation. See the attenuation page for more information.


Name Type Description
taskID int The Task ID obtained from niTuner_init that identifies the session of a particular device.
desiredRFFrequency double The desired frequency between 9 kHz and 2.7 GHz to which the PXI-5600 downconverter will tune.
span double The expected bandwidth of the RF input signal. You can specify a span value between 0 and 20 MHz. Span values affect phase noise and downconverter tuning step size, as shown below:

span settingphase noisetuning step size
<= 10 MHzbest5 MHz
> 10 MHzgood1 MHz

Default Value: 20 MHz

Note  The NI 5600 RF downconverter module hardware always downconverts a 20 MHz bandwidth. Software span settings are used to determine optimal phase noise/tuning step size combinations.
actualIFFrequency double * The actual IF center frequency. This frequency will be near or equal to 15 MHz, depending on the frequency step size determined from the span.
actualRFTunedFrequency double * The actual adjusted RF center frequency, based on the frequency step size determined by the span.
freqShift double * The difference between the actual RF center frequency and the actual IF center frequency.


Returns the status of the function. To see an explanation of common error and warning codes, see Error and Status Codes. To see a text explanation of the status code, call niTuner_errorHandler.