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NI FGEN Onboard Signal Processing Attributes

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Palash Khare edited this page Jun 4, 2021 · 1 revision

Signal Processing Attributes

NIFGEN_ATTRIBUTE_OSP_ENABLED

Specific Attribute

Numeric Value Data
type		 Access Applies to Coercion High Level Functions
1150246 ViBoolean R/W N/A None None

Description

Enables or disables the OSP block of the signal generator. When the OSP block is disabled, all OSP-related attributes are disabled and have no effect on the generated signal.

Defined Values

VI_TRUE Enables the OSP block of the signal generator.
VI_FALSE Disables the OSP block of the signal generator.

NIFGEN_ATTRIBUTE_OSP_IQ_RATE

Specific Attribute

Numeric Value Data
type		 Access Applies to Coercion High Level Functions
1150248 ViReal64 R/W N/A None None

Description

Specifies the rate at which the user-provided waveform data is generated when the NIFGEN_ATTRIBUTE_OSP_ENABLED attribute is set to VI_TRUE.

NI-FGEN sets the NIFGEN_ATTRIBUTE_ARB_SAMPLE_RATE attribute of the signal generator to the product of the values of the NIFGEN_ATTRIBUTE_OSP_IQ_RATE, NIFGEN_ATTRIBUTE_OSP_FIR_FILTER_INTERPOLATION, and NIFGEN_ATTRIBUTE_OSP_CIC_FILTER_INTERPOLATION attributes. When the NIFGEN_ATTRIBUTE_OSP_DATA_PROCESSING_MODE attribute is set to NIFGEN_VAL_OSP_REAL, the NIFGEN_ATTRIBUTE_OSP_IQ_RATE attribute is the rate at which the signal generator processes real (I) data. When the NIFGEN_ATTRIBUTE_OSP_DATA_PROCESSING_MODE attribute is set to NIFGEN_VAL_OSP_COMPLEX, the NIFGEN_ATTRIBUTE_OSP_IQ_RATE is the rate at which the signal generator processes complex (I/Q) data.

NIFGEN_ATTRIBUTE_OSP_DATA_PROCESSING_MODE

Specific Attribute

Numeric Value Data
type		 Access Applies to Coercion High Level Functions
1150247 ViInt32 R/W N/A None None

Description

Specifies the way in which data is processed by the OSP block.

Defined Values

NIFGEN_VAL_OSP_REAL The waveform data points are real numbers (I data).
NIFGEN_VAL_OSP_COMPLEX The waveform data points are complex numbers (I/Q data).

Note:  When using the NI 5450/5451 with I/Q rates higher than 200 MS/s, NI-FGEN restricts this attribute value to NIFGEN_VAL_OSP_COMPLEX.

NIFGEN_ATTRIBUTE_OSP_MODE

Specific Attribute

Numeric Value Data Type Access Applies to Coercion High-Level Functions
1150370 ViInt32 R/W N/A None None

Description

Specifies the generation mode of the OSP, which determines the type of data contained in the output signal.

For more information about the OSP modes your device supports, refer to the Devices section of the NI Signal Generators Help.

Defined Values

NIFGEN_VAL_OSP_IF The OSP block generates intermediate frequency (IF) data.
NIFGEN_VAL_OSP_BASEBAND The OSP block generates baseband data.

Note:  When using the NI 5450/5451 with I/Q rates higher than 200 MS/s, NI-FGEN restricts this attribute value to NIFGEN_VAL_OSP_BASEBAND.

NIFGEN_ATTRIBUTE_OSP_CARRIER_ENABLED

Specific Attribute

Numeric Value Data
type		 Access Applies to Coercion High Level Functions
1150249 ViBoolean R/W N/A None None

Description

Enables or disables generation of the carrier.

Defined Values

VI_TRUE Generation of the carrier is enabled.
VI_FALSE Generation of the carrier is disabled.

NIFGEN_ATTRIBUTE_OSP_CARRIER_FREQUENCY

Specific Attribute

Numeric Value Data
type		 Access Applies to Coercion High Level Functions
1150250 ViReal64 R/W N/A None None

Description

Specifies the frequency of the generated carrier.

NIFGEN_ATTRIBUTE_OSP_FREQUENCY_SHIFT

Specific Attribute

Numeric Value Data Type Access Applies to Coercion High-Level Functions
1150371 ViReal64 R/W Channel None None

Description

Specifies the amount of frequency shift applied to the baseband signal.

Note:  When using the NI 5450/5451 with I/Q rates higher than 200 MS/s, NI-FGEN restricts this attribute value to 0.

NIFGEN_ATTRIBUTE_OSP_FIR_FILTER_TYPE

Specific Attribute

Numeric Value Data
type		 Access Applies to Coercion High Level Functions
1150253 ViInt32 R/W N/A None None

Description

Specifies the pulse-shaping filter type for the FIR filter.

Defined Values:

NIFGEN_VAL_OSP_FLAT Applies a flat filter to the data with the passband value specified in the NIFGEN_ATTRIBUTE_OSP_FIR_FILTER_FLAT_PASSBAND attribute.
NIFGEN_VAL_OSP_RAISED_COSINE Applies a raised cosine filter to the data with the alpha value specified in the NIFGEN_ATTRIBUTE_OSP_FIR_FILTER_RAISED_COSINE_ALPHA attribute.
NIFGEN_VAL_OSP_ROOT_RAISED_COSINE Applies a root raised cosine filter to the data with the alpha value specified in the NIFGEN_ATTRIBUTE_OSP_FIR_FILTER_ROOT_RAISED_COSINE_ALPHA attribute.
NIFGEN_VAL_OSP_GAUSSIAN Applies a Gaussian filter to the data with the BT value specified in the NIFGEN_ATTRIBUTE_OSP_FIR_FILTER_GAUSSIAN_BT attribute.
NIFGEN_VAL_OSP_CUSTOM Applies a custom filter to the data. If NIFGEN_VAL_OSP_CUSTOM is selected, you must provide a set of FIR filter coefficients with the niFgen_ConfigureCustomFIRFilterCoefficients function.

NIFGEN_ATTRIBUTE_OSP_FIR_FILTER_FLAT_PASSBAND

Specific Attribute

Numeric Value Data
type		 Access Applies to Coercion High Level Functions
1150261 ViReal64 R/W N/A None None

Description

Specifies the passband value to use when calculating the FIR filter coefficients. The FIR filter is designed to be flat to passband x I/Q rate. This attribute is used only when the NIFGEN_ATTRIBUTE_OSP_FIR_FILTER_TYPE attribute is set to NIFGEN_VAL_OSP_FLAT.

NIFGEN_ATTRIBUTE_OSP_FIR_FILTER_RAISED_COSINE_ALPHA

Specific Attribute

Numeric Value Data
type		 Access Applies to Coercion High Level Functions
1150260 ViReal64 R/W N/A None None

Description

Specifies the alpha value to use when calculating the pulse shaping FIR filter coefficients. This attribute is used only when the NIFGEN_ATTRIBUTE_OSP_FIR_FILTER_TYPE attribute is set to NIFGEN_VAL_OSP_RAISED_COSINE.

NIFGEN_ATTRIBUTE_OSP_FIR_FILTER_ROOT_RAISED_COSINE_ALPHA

Specific Attribute

Numeric Value Data
type		 Access Applies to Coercion High Level Functions
1150259 ViReal64 R/W N/A None None

Description

Specifies the alpha value to use when calculating the pulse-shaping FIR filter coefficients. This attribute is used only when the NIFGEN_ATTRIBUTE_OSP_FIR_FILTER_TYPE attribute is set to NIFGEN_VAL_OSP_ROOT_RAISED_COSINE.

NIFGEN_ATTRIBUTE_OSP_FIR_FILTER_GAUSSIAN_BT

Specific Attribute

Numeric Value Data
type		 Access Applies to Coercion High Level Functions
1150262 ViReal64 R/W N/A None None

Description

Specifies the BT value to use when calculating the pulse-shaping FIR filter coefficients. The BT value is the product of the -3 dB bandwidth and the symbol period. This attribute is used only when the NIFGEN_ATTRIBUTE_OSP_FIR_FILTER_TYPE attribute is set to NIFGEN_VAL_OSP_GAUSSIAN.

NIFGEN_ATTRIBUTE_OSP_CARRIER_PHASE_I

Specific Attribute

Numeric Value Data
type		 Access Applies to Coercion High Level Functions
1150251 ViReal64 R/W N/A None None

Description

Specifies the I carrier phase, in degrees, at the first point of the generated signal.

Default Value: 0.0

NIFGEN_ATTRIBUTE_OSP_CARRIER_PHASE_Q

Specific Attribute

Numeric Value Data
type		 Access Applies to Coercion High Level Functions
1150252 ViReal64 R/W N/A None None

Description

Specifies the Q carrier phase, in degrees, at the first point of the generated signal. This attribute is used only when the NIFGEN_ATTRIBUTE_OSP_DATA_PROCESSING_MODE attribute is set to NIFGEN_VAL_OSP_COMPLEX.

Default Value: -90.0

NIFGEN_ATTRIBUTE_OSP_PRE_FILTER_GAIN_I

Specific Attribute

Numeric Value Data
type		 Access Applies to Coercion High Level Functions
1150264 ViReal64 R/W N/A None None

Description

Specifies the digital gain to apply to the I data stream before any filtering by the OSP block.

Defined Values: -2.0 to 2.0

Default Value: 1.0

NIFGEN_ATTRIBUTE_OSP_PRE_FILTER_GAIN_Q

Specific Attribute

Numeric Value Data
type		 Access Applies to Coercion High Level Functions
1150265 ViReal64 R/W N/A None None

Description

Specifies the digital gain to apply to the Q data stream before any filtering by the OSP block. This attribute is used only when the NIFGEN_ATTRIBUTE_OSP_DATA_PROCESSING_MODE attribute is set to NIFGEN_VAL_OSP_COMPLEX.

Defined Values: -2.0 to 2.0

Default Value: 1.0

NIFGEN_ATTRIBUTE_OSP_PRE_FILTER_OFFSET_I

Specific Attribute

Numeric Value Data
type		 Access Applies to Coercion High Level Functions
1150266 ViReal64 R/W N/A None None

Description

Specifies the digital offset to apply to the I data stream. This offset is applied after the prefilter gain and before any filtering.

Defined Values: Range is from -1.0 to 1.0

Default Value: 0.9

NIFGEN_ATTRIBUTE_OSP_PRE_FILTER_OFFSET_Q

Specific Attribute

Numeric Value Data
type		 Access Applies to Coercion High Level Functions
1150267 ViReal64 R/W N/A None None

Description

Specifies the digital offset to apply to the Q data stream. This offset is applied after the prefilter gain and before any filtering. This attribute is used only when the NIFGEN_ATTRIBUTE_OSP_DATA_PROCESSING_MODE attribute is set to NIFGEN_VAL_OSP_COMPLEX.

Defined Values: Range is from -1.0 to 1.0

Default Value: 0.0

NIFGEN_ATTRIBUTE_OSP_FIR_FILTER_ENABLED

Specific Attribute

Numeric Value Data
type		 Access Applies to Coercion High Level Functions
1150255 ViBoolean R/W N/A None None

Description

Enables or disables the FIR filter.

Note:  You must set the NIFGEN_ATTRIBUTE_OSP_CIC_FILTER_ENABLED and NIFGEN_ATTRIBUTE_OSP_FIR_FILTER_ENABLED attributes to the same value.

Defined Values

VI_TRUE The FIR filter is enabled.
VI_FALSE The FIR filter is disabled.

NIFGEN_ATTRIBUTE_OSP_FIR_FILTER_INTERPOLATION

Specific Attribute

Numeric Value Data
type		 Access Applies to Coercion High Level Functions
1150256 ViReal64 R/W N/A None None

Description

Specifies the interpolation factor for the FIR filter. If you do not set this value, NI-FGEN calculates the appropriate value based on the value of the NIFGEN_ATTRIBUTE_OSP_IQ_RATE attribute.

NIFGEN_ATTRIBUTE_OSP_CIC_FILTER_ENABLED

Specific Attribute

Numeric Value Data
type		 Access Applies to Coercion High Level Functions
1150257 ViBoolean R/W N/A None None

Description

Enables or disables the CIC filter.

Note:  You must set the NIFGEN_ATTRIBUTE_OSP_CIC_FILTER_ENABLED and NIFGEN_ATTRIBUTE_OSP_FIR_FILTER_ENABLED attributes to the same value.

Defined Values

VI_TRUE Enables the CIC filter.
VI_FALSE Disables the CIC filter.

NIFGEN_ATTRIBUTE_OSP_CIC_FILTER_GAIN

Specific Attribute

Numeric Value Data
type		 Access Applies to Coercion High Level Functions
1150263 ViReal64 R/W N/A None None

Description

Specifies the gain applied at the final stage of the CIC filter. This attribute is commonly used to compensate for attenuation in the FIR filter. If you set the NIFGEN_ATTRIBUTE_OSP_FIR_FILTER_TYPE attribute to NIFGEN_VAL_OSP_CUSTOM, NI-FGEN calculates the CIC gain to achieve unity gain between the FIR and CIC filters. Setting this attribute overrides the value set by NI-FGEN.

NIFGEN_ATTRIBUTE_OSP_CIC_FILTER_INTERPOLATION

Specific Attribute

Numeric Value Data
type		 Access Applies to Coercion High Level Functions
1150258 ViReal64 R/W N/A None None

Description

Specifies the interpolation factor for the CIC filter. If you do not set this value, NI-FGEN calculates the appropriate value based on the value of the NIFGEN_ATTRIBUTE_OSP_IQ_RATE attribute.

NIFGEN_ATTRIBUTE_OSP_COMPENSATE_FOR_FILTER_GROUP_DELAY

Specific Attribute

Numeric Value Data
type		 Access Applies to Coercion High Level Functions
1150389 ViBoolean R/W N/A None None

Description

Adjusts for OSP filter group delay when aligning analog outputs and events in OSP mode. If this attribute is enabled, event outputs align more closely with the analog output. The analog output also aligns more closely between two devices synchronized using NI-TClk.

Note:  Group delay is the delay that occurs as a result of passing through a FIR filter. At a low I/Q rate, the group delay can become so large that some devices may not be able to align the events with the output. In this case, you must increase the I/Q rate or disable this attribute.

Defined Values

VI_TRUE Compensation for the filter group delay is enabled.
VI_FALSE Compensation for the filter group delay is disabled.

NIFGEN_ATTRIBUTE_OSP_OVERFLOW_ERROR_REPORTING

Specific Attribute

Numeric Value Data
type		 Access Applies to Coercion High Level Functions
1150268 ViInt32 R/W N/A None None

Description

Configures error reporting when the OSP block detects an overflow in any of its stages. Overflows lead to clipping of the waveform.

You can use the NIFGEN_ATTRIBUTE_OSP_OVERFLOW_STATUS attribute to query for overflow conditions regardless of the setting of the NIFGEN_ATTRIBUTE_OSP_OVERFLOW_ERROR_REPORTING attribute. The device continues to generate after an overflow, regardless of the value you select.

Defined Values

NIFGEN_VAL_ERROR_REPORTING_ERROR NI-FGEN returns errors whenever an overflow has occurred in the OSP block.
NIFGEN_VAL_ERROR_REPORTING_DISABLED NI-FGEN does not return errors when an overflow occurs in the OSP block.

NIFGEN_ATTRIBUTE_OSP_OVERFLOW_STATUS

Specific Attribute

Numeric Value Data
type		 Access Applies to Coercion High Level Functions
1150269 ViInt32 R/W N/A None None

Description

Returns a bit field of the overflow status in any stage of the OSP block. This attribute is functional regardless of the value for the NIFGEN_ATTRIBUTE_OSP_OVERFLOW_ERROR_REPORTING attribute.

Write 0 to this attribute to clear the current NIFGEN_ATTRIBUTE_OSP_OVERFLOW_ERROR_REPORTING value.

Defined Values

NIFGEN_VAL_OSP_OVERFLOW_NONE None - 0x0
NIFGEN_VAL_OSP_OVERFLOW_PRE_FILTER_GAIN_I Pre-filter gain I - 0x1
NIFGEN_VAL_OSP_OVERFLOW_PRE_FILTER_GAIN_Q Pre-filter gain Q - 0x2
NIFGEN_VAL_OSP_OVERFLOW_PRE_FILTER_OFFSET_I Pre-filter offset I - 0x4
NIFGEN_VAL_OSP_OVERFLOW_PRE_FILTER_OFFSET_Q Pre-filter offset Q - 0x8
NIFGEN_VAL_OSP_OVERFLOW_FIR_FILTER_I FIR filter I - 0x10
NIFGEN_VAL_OSP_OVERFLOW_FIR_FILTER_Q FIR filter Q - 0x20
NIFGEN_VAL_OSP_OVERFLOW_CIC_FILTER_I CIC filter I - 0x40
NIFGEN_VAL_OSP_OVERFLOW_CIC_FILTER_Q CIC filter Q - 0x80
NIFGEN_VAL_OSP_OVERFLOW_COMPLEX_DATA 0x100

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