NI-RFmx Demod 3.0 Help

Edition Date: January 2019

Part Number: 374641K-01

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int32 __stdcall RFmxDemod_ADemodFetchDemodSpectrumTrace (niRFmxInstrHandle instrumentHandle, char selectorString[], float64 timeout, float64* x0, float64* dx, float32 demodulatedSpectrum[], int32 arraySize, int32* actualArraySize);


Fetches the demodulated signal spectrum trace.


Name Type Description
instrumentHandle niRFmxInstrHandle Specifies the RFmx session. You can obtain this parameter from the RFmxDemod_Initialize function.
selectorString char[]

Comprises the signal name and result name. If you do not specify the signal name, the default signal instance is used.






You can use the RFmxDemod_BuildSignalString function to build the selector string.

timeout float64 specifies the time, in seconds, for which the function waits for the measurement to complete. A value of -1 specifies that the function waits until the measurement is complete.
arraySize int32 Specifies the size of the y array. Set the arraySize parameter to 0 to get the size of the y array in the actualArraySize parameter.
Name Type Description
x0 float64* Returns the start bin frequency, in Hz.
dx float64* Returns the frequency bin spacing, in Hz.
demodulatedSpectrum float32[] Returns the signal amplitude, as a percentage for AM, in Hz for FM, and in degrees for PM signals, measured at each frequency bin. To get the size of y array, set arraySize parameter to 0. You can pass NULL for this parameter if the arraySize is set to 0. If the y array is not large enough to hold all the samples, the function returns an error.
actualArraySize int32* Returns the actual size of the array, if you pass NULL to all output array parameters, and set the arraySize parameter to 0.

Return Value

Name Type Description
status int32 Returns the status code of this operation. The status code either indicates success or describes an error or warning condition. Examine the status code from each call to an RFmx function to determine if an error has occurred.

To obtain a text description of the status code and additional information about the error condition, call the RFmxDemod_GetError function.

The general meaning of the status code is as follows:

Value Meaning
0 Success
Positive Values Warnings
Negative Values Errors


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