NI RFmx SpecAn OBW Attributes

OBW Attributes

• RFMXSPECAN_ATTR_OBW_MEASUREMENT_ENABLED
• RFMXSPECAN_ATTR_OBW_SPAN
• RFMXSPECAN_ATTR_OBW_BANDWIDTH_PERCENTAGE
• RFMXSPECAN_ATTR_OBW_POWER_UNITS
• RBW Filter
  • RFMXSPECAN_ATTR_OBW_RBW_FILTER_AUTO_BANDWIDTH
  • RFMXSPECAN_ATTR_OBW_RBW_FILTER_BANDWIDTH
  • RFMXSPECAN_ATTR_OBW_RBW_FILTER_TYPE
  • RFMXSPECAN_ATTR_OBW_RBW_FILTER_BANDWIDTH_DEFINITION
• Sweep Time
  • RFMXSPECAN_ATTR_OBW_SWEEP_TIME_AUTO
  • RFMXSPECAN_ATTR_OBW_SWEEP_TIME_INTERVAL
• Averaging
  • RFMXSPECAN_ATTR_OBW_AVERAGING_ENABLED
  • RFMXSPECAN_ATTR_OBW_AVERAGING_COUNT
  • RFMXSPECAN_ATTR_OBW_AVERAGING_TYPE
• FFT
  • RFMXSPECAN_ATTR_OBW_FFT_WINDOW
  • RFMXSPECAN_ATTR_OBW_FFT_PADDING
• RFMXSPECAN_ATTR_OBW_AMPLITUDE_CORRECTION_TYPE
• RFMXSPECAN_ATTR_OBW_ALL_TRACES_ENABLED
• RFMXSPECAN_ATTR_OBW_NUMBER_OF_ANALYSIS_THREADS
• Results
  • RFMXSPECAN_ATTR_OBW_RESULTS_OCCUPIED_BANDWIDTH
  • RFMXSPECAN_ATTR_OBW_RESULTS_AVERAGE_POWER
  • RFMXSPECAN_ATTR_OBW_RESULTS_START_FREQUENCY
  • RFMXSPECAN_ATTR_OBW_RESULTS_STOP_FREQUENCY
  • RFMXSPECAN_ATTR_OBW_RESULTS_FREQUENCY_RESOLUTION

RFMXSPECAN_ATTR_OBW_MEASUREMENT_ENABLED

Data Type:	int32
Access:	read/write
Functions:	RFmxSpecAn_SetAttributeI32 RFmxSpecAn_GetAttributeI32
Description:	Specifies whether to enable OBW measurement. You do not need to use a selector string to configure or read this attribute for the default signal instance. Refer to the Selector Strings topic for information about the string syntax for named signals. The default value is RFMXSPECAN_VAL_FALSE. Get Function: RFmxSpecAn_OBWGetMeasurementEnabled Set Function: RFmxSpecAn_OBWSetMeasurementEnabled

RFMXSPECAN_ATTR_OBW_SPAN

Data Type:	float64
Access:	read/write
Functions:	RFmxSpecAn_SetAttributeF64 RFmxSpecAn_GetAttributeF64
Description:	Specifies the frequency range around the center frequency, to acquire for the measurement. This value is expressed in Hz. You do not need to use a selector string to configure or read this attribute for the default signal instance. Refer to the Selector Strings topic for information about the string syntax for named signals. The default value is 1 MHz. Get Function: RFmxSpecAn_OBWGetSpan Set Function: RFmxSpecAn_OBWSetSpan

RFMXSPECAN_ATTR_OBW_BANDWIDTH_PERCENTAGE

Data Type:	float64
Access:	read/write
Functions:	RFmxSpecAn_SetAttributeF64 RFmxSpecAn_GetAttributeF64
Description:	Specifies the percentage of the total power that is contained in the OBW. You do not need to use a selector string to configure or read this attribute for the default signal instance. Refer to the Selector Strings topic for information about the string syntax for named signals. The default value is 99%. Get Function: RFmxSpecAn_OBWGetBandwidthPercentage Set Function: RFmxSpecAn_OBWSetBandwidthPercentage

RFMXSPECAN_ATTR_OBW_POWER_UNITS

Data Type:	int32
Access:	read/write
Functions:	RFmxSpecAn_SetAttributeI32 RFmxSpecAn_GetAttributeI32
Description:	Specifies the units for the absolute power. You do not need to use a selector string to configure or read this attribute for the default signal instance. Refer to the Selector Strings topic for information about the string syntax for named signals. The default value is RFMXSPECAN_VAL_OBW_POWER_UNITS_DBM_PER_HZ. Get Function: RFmxSpecAn_OBWGetPowerUnits Set Function: RFmxSpecAn_OBWSetPowerUnits
Values:

RFMXSPECAN_VAL_OBW_POWER_UNITS_DBM (0)	The absolute powers are reported in dBm.
RFMXSPECAN_VAL_OBW_POWER_UNITS_DBM_PER_HZ (1)	The absolute powers are reported in dBm/Hz.

OBW RBW Filter

RFMXSPECAN_ATTR_OBW_RBW_FILTER_AUTO_BANDWIDTH

Data Type:	int32
Access:	read/write
Functions:	RFmxSpecAn_SetAttributeI32 RFmxSpecAn_GetAttributeI32
Description:	Specifies whether the measurement computes the resolution bandwidth (RBW). You do not need to use a selector string to configure or read this attribute for the default signal instance. Refer to the Selector Strings topic for information about the string syntax for named signals. The default value is RFMXSPECAN_VAL_OBW_RBW_AUTO_TRUE. Get Function: RFmxSpecAn_OBWGetRBWFilterAutoBandwidth Set Function: RFmxSpecAn_OBWSetRBWFilterAutoBandwidth
Values:

RFMXSPECAN_VAL_OBW_RBW_AUTO_FALSE (0)	The measurement uses the RBW that you specify in the RFMXSPECAN_ATTR_OBW_RBW_FILTER_BANDWIDTH attribute.
RFMXSPECAN_VAL_OBW_RBW_AUTO_TRUE (1)	The measurement computes the RBW.

RFMXSPECAN_ATTR_OBW_RBW_FILTER_BANDWIDTH

Data Type:	float64
Access:	read/write
Functions:	RFmxSpecAn_SetAttributeF64 RFmxSpecAn_GetAttributeF64
Description:	Specifies the bandwidth of the resolution bandwidth (RBW) filter used to sweep the acquired signal, when you set the RFMXSPECAN_ATTR_OBW_RBW_FILTER_AUTO_BANDWIDTH attribute to RFMXSPECAN_VAL_OBW_RBW_AUTO_FALSE. This value is expressed in Hz. You do not need to use a selector string to configure or read this attribute for the default signal instance. Refer to the Selector Strings topic for information about the string syntax for named signals. The default value is 10 kHz. Get Function: RFmxSpecAn_OBWGetRBWFilterBandwidth Set Function: RFmxSpecAn_OBWSetRBWFilterBandwidth

RFMXSPECAN_ATTR_OBW_RBW_FILTER_TYPE

Data Type:	int32
Access:	read/write
Functions:	RFmxSpecAn_SetAttributeI32 RFmxSpecAn_GetAttributeI32
Description:	Specifies the shape of the digital resolution bandwidth (RBW) filter. You do not need to use a selector string to configure or read this attribute for the default signal instance. Refer to the Selector Strings topic for information about the string syntax for named signals. The default value is RFMXSPECAN_VAL_OBW_RBW_FILTER_TYPE_GAUSSIAN. Get Function: RFmxSpecAn_OBWGetRBWFilterType Set Function: RFmxSpecAn_OBWSetRBWFilterType
Values:

RFMXSPECAN_VAL_OBW_RBW_FILTER_TYPE_FFT_BASED (0)	No RBW filtering is performed.
RFMXSPECAN_VAL_OBW_RBW_FILTER_TYPE_GAUSSIAN (1)	The RBW filter has a Gaussian response.
RFMXSPECAN_VAL_OBW_RBW_FILTER_TYPE_FLAT (2)	The RBW filter has a flat response.

RFMXSPECAN_ATTR_OBW_RBW_FILTER_BANDWIDTH_DEFINITION

Data Type:	int32
Access:	read/write
Functions:	RFmxSpecAn_SetAttributeI32 RFmxSpecAn_GetAttributeI32
Description:	Specifies the bandwidth definition that you use to specify the value of the RFMXSPECAN_ATTR_OBW_RBW_FILTER_BANDWIDTH attribute. The default value is RFMXSPECAN_VAL_OBW_RBW_FILTER_BANDWIDTH_DEFINITION_3DB. Get Function: RFmxSpecAn_OBWGetRBWFilterBandwidthDefinition Set Function: RFmxSpecAn_OBWSetRBWFilterBandwidthDefinition
Values:

RFMXSPECAN_VAL_OBW_RBW_FILTER_BANDWIDTH_DEFINITION_3DB (0)	Defines the RBW in terms of the 3 dB bandwidth of the RBW filter. When you set the RFMXSPECAN_ATTR_OBW_RBW_FILTER_TYPE attribute to RFMXSPECAN_VAL_OBW_RBW_FILTER_TYPE_FFT_BASED, RBW is the 3 dB bandwidth of the window specified by the RFMXSPECAN_ATTR_OBW_FFT_WINDOW attribute.
RFMXSPECAN_VAL_OBW_RBW_FILTER_BANDWIDTH_DEFINITION_BIN_WIDTH (2)	Defines the RBW in terms of the spectrum bin width computed using an FFT when you set the RFMXSPECAN_ATTR_OBW_RBW_FILTER_TYPE attribute to FFT Based.

OBW Sweep Time

RFMXSPECAN_ATTR_OBW_SWEEP_TIME_AUTO

Data Type:	int32
Access:	read/write
Functions:	RFmxSpecAn_SetAttributeI32 RFmxSpecAn_GetAttributeI32
Description:	Specifies whether the measurement computes the sweep time. You do not need to use a selector string to configure or read this attribute for the default signal instance. Refer to the Selector Strings topic for information about the string syntax for named signals. The default value is RFMXSPECAN_VAL_OBW_SWEEP_TIME_AUTO_TRUE. Get Function: RFmxSpecAn_OBWGetSweepTimeAuto Set Function: RFmxSpecAn_OBWSetSweepTimeAuto
Values:

RFMXSPECAN_VAL_OBW_SWEEP_TIME_AUTO_FALSE (0)	The measurement uses the sweep time that you specify in the RFMXSPECAN_ATTR_OBW_SWEEP_TIME_INTERVAL attribute.
RFMXSPECAN_VAL_OBW_SWEEP_TIME_AUTO_TRUE (1)	The measurement calculates the sweep time based on the value of the RFMXSPECAN_ATTR_OBW_RBW_FILTER_BANDWIDTH attribute.

RFMXSPECAN_ATTR_OBW_SWEEP_TIME_INTERVAL

Data Type:	float64
Access:	read/write
Functions:	RFmxSpecAn_SetAttributeF64 RFmxSpecAn_GetAttributeF64
Description:	Specifies the sweep time when you set the RFMXSPECAN_ATTR_OBW_SWEEP_TIME_AUTO attribute to RFMXSPECAN_VAL_OBW_SWEEP_TIME_AUTO_FALSE. This value is expressed in seconds. You do not need to use a selector string to configure or read this attribute for the default signal instance. Refer to the Selector Strings topic for information about the string syntax for named signals. The default value is 0.001. Get Function: RFmxSpecAn_OBWGetSweepTimeInterval Set Function: RFmxSpecAn_OBWSetSweepTimeInterval

OBW Averaging

RFMXSPECAN_ATTR_OBW_AVERAGING_ENABLED

Data Type:	int32
Access:	read/write
Functions:	RFmxSpecAn_SetAttributeI32 RFmxSpecAn_GetAttributeI32
Description:	Specifies whether to enable averaging for the OBW measurement. You do not need to use a selector string to configure or read this attribute for the default signal instance. Refer to the Selector Strings topic for information about the string syntax for named signals. The default value is RFMXSPECAN_VAL_OBW_AVERAGING_ENABLED_FALSE. Get Function: RFmxSpecAn_OBWGetAveragingEnabled Set Function: RFmxSpecAn_OBWSetAveragingEnabled
Values:

RFMXSPECAN_VAL_OBW_AVERAGING_ENABLED_FALSE (0)	The measurement is performed on a single acquisition.
RFMXSPECAN_VAL_OBW_AVERAGING_ENABLED_TRUE (1)	The OBW measurement uses the RFMXSPECAN_ATTR_OBW_AVERAGING_COUNT attribute as the number of acquisitions over which the OBW measurement is averaged.

RFMXSPECAN_ATTR_OBW_AVERAGING_COUNT

Data Type:	int32
Access:	read/write
Functions:	RFmxSpecAn_SetAttributeI32 RFmxSpecAn_GetAttributeI32
Description:	Specifies the number of acquisitions used for averaging when you set the RFMXSPECAN_ATTR_OBW_AVERAGING_ENABLED attribute to RFMXSPECAN_VAL_OBW_AVERAGING_ENABLED_TRUE. You do not need to use a selector string to configure or read this attribute for the default signal instance. Refer to the Selector Strings topic for information about the string syntax for named signals. The default value is 10. Get Function: RFmxSpecAn_OBWGetAveragingCount Set Function: RFmxSpecAn_OBWSetAveragingCount

RFMXSPECAN_ATTR_OBW_AVERAGING_TYPE

Data Type:	int32
Access:	read/write
Functions:	RFmxSpecAn_SetAttributeI32 RFmxSpecAn_GetAttributeI32
Description:	Specifies the averaging type for averaging multiple spectrum acquisitions. The averaged spectrum is used for OBW measurement. You do not need to use a selector string to configure or read this attribute for the default signal instance. Refer to the Selector Strings topic for information about the string syntax for named signals. The default value is RFMXSPECAN_VAL_OBW_AVERAGING_TYPE_RMS. Get Function: RFmxSpecAn_OBWGetAveragingType Set Function: RFmxSpecAn_OBWSetAveragingType
Values:

RFMXSPECAN_VAL_OBW_AVERAGING_TYPE_RMS (0)	The power spectrum is linearly averaged. RMS averaging reduces signal fluctuations but not the noise floor.
RFMXSPECAN_VAL_OBW_AVERAGING_TYPE_LOG (1)	The power spectrum is averaged in a logarithmic scale.
RFMXSPECAN_VAL_OBW_AVERAGING_TYPE_SCALAR (2)	The square root of the power spectrum is averaged.
RFMXSPECAN_VAL_OBW_AVERAGING_TYPE_MAXIMUM (3)	The peak power in the spectrum at each frequency bin is retained from one acquisition to the next.
RFMXSPECAN_VAL_OBW_AVERAGING_TYPE_MINIMUM (4)	The least power in the spectrum at each frequency bin is retained from one acquisition to the next.

OBW FFT

RFMXSPECAN_ATTR_OBW_FFT_WINDOW

Data Type:	int32
Access:	read/write
Functions:	RFmxSpecAn_SetAttributeI32 RFmxSpecAn_GetAttributeI32
Description:	Specifies the FFT window type to use to reduce spectral leakage. You do not need to use a selector string to configure or read this attribute for the default signal instance. Refer to the Selector Strings topic for information about the string syntax for named signals. The default value is RFMXSPECAN_VAL_OBW_FFT_WINDOW_FLAT_TOP. Get Function: RFmxSpecAn_OBWGetFFTWindow Set Function: RFmxSpecAn_OBWSetFFTWindow
Values:

RFMXSPECAN_VAL_OBW_FFT_WINDOW_NONE (0)	Analyzes transients for which duration is shorter than the window length. You can also use this window type to separate two tones with frequencies close to each other but with almost equal amplitudes.
RFMXSPECAN_VAL_OBW_FFT_WINDOW_FLAT_TOP (1)	Measures single-tone amplitudes accurately.
RFMXSPECAN_VAL_OBW_FFT_WINDOW_HANNING (2)	Analyzes transients for which duration is longer than the window length. You can also use this window type to provide better frequency resolution for noise measurements.
RFMXSPECAN_VAL_OBW_FFT_WINDOW_HAMMING (3)	Analyzes closely-spaced sine waves.
RFMXSPECAN_VAL_OBW_FFT_WINDOW_GAUSSIAN (4)	Provides a good balance of spectral leakage, frequency resolution, and amplitude attenuation. Hence, this windowing is useful for time-frequency analysis.
RFMXSPECAN_VAL_OBW_FFT_WINDOW_BLACKMAN (5)	Analyzes single tone because it has a low maximum side lobe level and a high side lobe roll-off rate.
RFMXSPECAN_VAL_OBW_FFT_WINDOW_BLACKMAN_HARRIS (6)	Useful as a good general purpose window, having side lobe rejection greater than 90 dB and having a moderately wide main lobe.
RFMXSPECAN_VAL_OBW_FFT_WINDOW_KAISER_BESSEL (7)	Separates two tones with frequencies close to each other but with widely-differing amplitudes.

RFMXSPECAN_ATTR_OBW_FFT_PADDING

Data Type:	float64
Access:	read/write
Functions:	RFmxSpecAn_SetAttributeF64 RFmxSpecAn_GetAttributeF64
Description:	Specifies the factor by which the time-domain waveform is zero-padded before fast Fourier transform (FFT). The FFT size is given by the following formula: waveform size * padding This attribute is used only when the acquisition span is less than the device instantaneous bandwidth of the device. You do not need to use a selector string to configure or read this attribute for the default signal instance. Refer to the Selector Strings topic for information about the string syntax for named signals. The default value is -1. Get Function: RFmxSpecAn_OBWGetFFTPadding Set Function: RFmxSpecAn_OBWSetFFTPadding

RFMXSPECAN_ATTR_OBW_AMPLITUDE_CORRECTION_TYPE

Data Type:	int32
Access:	read/write
Functions:	RFmxSpecAn_SetAttributeI32 RFmxSpecAn_GetAttributeI32
Description:	Specifies whether the amplitude of the frequency bins, used in the measurement, is corrected for external attenuation at the RF center frequency, or at the individual frequency bins. Use the RFmxInstr_CfgExternalAttenuationTable function to configure the external attenuation table. You do not need to use a selector string to configure or read this attribute for the default signal instance. Refer to the Selector Strings topic for information about the string syntax for named signals. The default value is RFMXSPECAN_VAL_OBW_AMPLITUDE_CORRECTION_TYPE_RF_CENTER_FREQUENCY. Get Function: RFmxSpecAn_OBWGetAmplitudeCorrectionType Set Function: RFmxSpecAn_OBWSetAmplitudeCorrectionType
Values:

RFMXSPECAN_VAL_OBW_AMPLITUDE_CORRECTION_TYPE_RF_CENTER_FREQUENCY (0)	All the frequency bins in the spectrum are compensated with a single external attenuation value that corresponds to the RF center frequency.
RFMXSPECAN_VAL_OBW_AMPLITUDE_CORRECTION_TYPE_SPECTRUM_FREQUENCY_BIN (1)	An individual frequency bin in the spectrum is compensated with the external attenuation value corresponding to that frequency.

RFMXSPECAN_ATTR_OBW_ALL_TRACES_ENABLED

Data Type:	int32
Access:	read/write
Functions:	RFmxSpecAn_SetAttributeI32 RFmxSpecAn_GetAttributeI32
Description:	Specifies whether to enable the traces to be stored and retrieved after performing the OBW. You do not need to use a selector string to configure or read this attribute for the default signal instance. Refer to the Selector Strings topic for information about the string syntax for named signals. The default value is RFMXSPECAN_VAL_FALSE. Get Function: RFmxSpecAn_OBWGetAllTracesEnabled Set Function: RFmxSpecAn_OBWSetAllTracesEnabled

RFMXSPECAN_ATTR_OBW_NUMBER_OF_ANALYSIS_THREADS

Data Type:	int32
Access:	read/write
Functions:	RFmxSpecAn_SetAttributeI32 RFmxSpecAn_GetAttributeI32
Description:	Specifies the maximum number of threads used for parallelism for the OBW measurement. The number of threads can range from 1 to the number of physical cores. The number of threads you set may not be used in calculations. The actual number of threads used depends on the problem size, system resources, data availability, and other considerations. You do not need to use a selector string to configure or read this attribute for the default signal instance. Refer to the Selector Strings topic for information about the string syntax for named signals. The default value is 1. Get Function: RFmxSpecAn_OBWGetNumberOfAnalysisThreads Set Function: RFmxSpecAn_OBWSetNumberOfAnalysisThreads

OBW Results

RFMXSPECAN_ATTR_OBW_RESULTS_OCCUPIED_BANDWIDTH

Data Type:	float64
Access:	read only
Functions:	RFmxSpecAn_GetAttributeF64
Description:	Returns the bandwidth that occupies the percentage of the total power of the signal that you specify in the RFMXSPECAN_ATTR_OBW_BANDWIDTH_PERCENTAGE attribute. This value is expressed in Hz. You do not need to use a selector string to read this result for default signal and result instance. Refer to the Selector Strings topic for information about the string syntax for named signals and results. Get Function: RFmxSpecAn_OBWGetResultsOccupiedBandwidth

RFMXSPECAN_ATTR_OBW_RESULTS_AVERAGE_POWER

Data Type:	float64
Access:	read only
Functions:	RFmxSpecAn_GetAttributeF64
Description:	Returns the total integrated power, in dBm, of the averaged spectrum acquired by the OBW measurement when you set the RFMXSPECAN_ATTR_OBW_POWER_UNITS attribute to RFMXSPECAN_VAL_OBW_POWER_UNITS_DBM. The RFMXSPECAN_ATTR_OBW_RESULTS_AVERAGE_POWER attribute returns the power spectral density, in dBm/Hz, when you set the RFMXSPECAN_ATTR_OBW_POWER_UNITS attribute to RFMXSPECAN_VAL_OBW_POWER_UNITS_DBM_PER_HZ. You do not need to use a selector string to read this result for default signal and result instance. Refer to the Selector Strings topic for information about the string syntax for named signals and results. Get Function: RFmxSpecAn_OBWGetResultsAveragePower

RFMXSPECAN_ATTR_OBW_RESULTS_START_FREQUENCY

Data Type:	float64
Access:	read only
Functions:	RFmxSpecAn_GetAttributeF64
Description:	Returns the start frequency of the OBW. This value is expressed in Hz. The OBW is calculated using the following formula: OBW = stop frequency - start frequency You do not need to use a selector string to read this result for default signal and result instance. Refer to the Selector Strings topic for information about the string syntax for named signals and results. Get Function: RFmxSpecAn_OBWGetResultsStartFrequency

RFMXSPECAN_ATTR_OBW_RESULTS_STOP_FREQUENCY

Data Type:	float64
Access:	read only
Functions:	RFmxSpecAn_GetAttributeF64
Description:	Returns the stop frequency of the OBW. This value is expressed in Hz. The OBW is calculated using the following formula: OBW = stop frequency - start frequency You do not need to use a selector string to read this result for default signal and result instance. Refer to the Selector Strings topic for information about the string syntax for named signals and results. Get Function: RFmxSpecAn_OBWGetResultsStopFrequency

RFMXSPECAN_ATTR_OBW_RESULTS_FREQUENCY_RESOLUTION

Data Type:	float64
Access:	read only
Functions:	RFmxSpecAn_GetAttributeF64
Description:	Returns the frequency bin spacing of the spectrum acquired by the OBW measurement. This value is expressed in Hz. You do not need to use a selector string to read this result for default signal and result instance. Refer to the Selector Strings topic for information about the string syntax for named signals and results. Get Function: RFmxSpecAn_OBWGetResultsFrequencyResolution