NI RFmx LTE OBW Fetch Functions

OBW Fetch Functions

• RFmxLTE_OBWFetchMeasurement
• RFmxLTE_OBWFetchSpectrum

RFmxLTE_OBWFetchMeasurement

int32 __stdcall RFmxLTE_OBWFetchMeasurement (niRFmxInstrHandle instrumentHandle, char selectorString[], float64 timeout, float64* occupiedBandwidth, float64* absolutePower, float64* startFrequency, float64* stopFrequency);

Purpose

Returns the occupied bandwidth, absolute power, start frequency, and stop frequency of a component carrier or subblock. Use "subblock<n>" as the selector string to read results from this function. Refer to the LTE Occupied Bandwidth) topic for more information about OBW measurements.

Parameters

Input
Name	Type	Description
instrumentHandle	niRFmxInstrHandle	Specifies the instrument session. The RFmx obtains this parameter from the RFmxLTE_Initialize) function.
selectorString	char[]	Specifies a selector string) comprising of the signal name, result name, and subblock number. If you do not specify the signal name, the default signal instance is used. If you do not specify the result name, the default result instance is used. Example: "subblock0" "signal::sig1/subblock0" "result::r1/subblock0" "signal::sig1/result::r1/subblock0" You can use the RFmxLTE_BuildSubblockString) function to build the selector string.
timeout	float64	Specifies the timeout, in seconds, for fetching the specified measurement. Set this value to an appropriate time, longer than expected for fetching the measurement. A value of -1 specifies that the function waits until the measurement is complete.
Output
Name	Type	Description
occupiedBandwidth	float64*	Returns the bandwidth that occupies 99 percentage of the total power of the signal within a carrier/subblock.
absolutePower	float64*	Returns the power measured over the integration bandwidth of the carrier/subblock.
startFrequency	float64*	Returns the start frequency of the subblock. The occupied bandwidth of a carrier/subblock is calculated using the following equation: Stop frequency - Start frequency = Occupied bandwidth.
stopFrequency	float64*	Returns the stop frequency of the subblock. The occupied bandwidth of a carrier/subblock is calculated using the following equation: Stop frequency - Start frequency = Occupied bandwidth.

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 RFmxLTE_GetError) function. The general meaning of the status code is as follows:

Value	Meaning
0	Success
Positive Values	Warnings
Negative Values	Errors

RFmxLTE_OBWFetchSpectrum

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

Purpose

Fetches the spectrum used for OBW measurements.

Parameters

Input
Name	Type	Description
instrumentHandle	niRFmxInstrHandle	Specifies the instrument session. The RFmx obtains this parameter from the RFmxLTE_Initialize) function.
selectorString	char[]	Specifies a selector string) comprising of the signal name and the result name. If you do not specify the signal name, the default signal instance is used. If you do not specify the result name, the default result instance is used. Example: "signal::sig1" "result::r1" "signal::sig1/result::r1" You can use the RFmxLTE_BuildSignalString) function to build the selector string.
timeout	float64	Specifies the timeout, in seconds, for fetching the specified measurement. Set this value to an appropriate time, longer than expected for fetching the measurement. A value of -1 specifies that the function waits until the measurement is complete.
arraySize	int32	Specifies the size of the array. Set the arraySize parameter to 0 to get the size of all the arrays in the actualArraySize parameter.
Output
Name	Type	Description
x0	float64*	Returns the start frequency of the channel. This value is expressed in Hz.
dx	float64*	Returns the frequency bin spacing. This value is expressed in Hz.
spectrum	float32[]	Returns the array of averaged power measured at each frequency bin. This value is expressed in dBm.
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 RFmxLTE_GetError) function. The general meaning of the status code is as follows:

Value	Meaning
0	Success
Positive Values	Warnings
Negative Values	Errors