NI 5441
IQ Rate

IQ Rate defines the rate at which data is processed by the OSP block. If the Data Processing Mode property is set to Real or the NIFGEN_ATTR_OSP_DATA_PROCESSING_MODE attribute is set to NIFGEN_VAL_OSP_REAL, then it is the rate at which each sample from waveform memory is taken from memory and inserted into the OSP block. If the Data Processing Mode property is set to Complex NIFGEN_ATTR_OSP_DATA_PROCESSING_MODE attribute is set to NIFGEN_VAL_OSP_COMPLEX, then it is the rate at which each complex sample is taken from memory and inserted into the OSP block.

The actual sample rate is calculated by NI-FGEN based on the IQ Rate. NI-FGEN calculates the FIR Interpolation Factor and CIC Interpolation Factor properties or the NIFGEN_ATTR_OSP_FIR_FILTER_INTERPOLATION and NIFGEN_ATTR_OSP_CIC_FILTER_INTERPOLATION attributes unless you set them. The following formula describes the relationship between the IQ rate, FIR interpolation rate, CIC interpolation rate, and sample rate:

Sample Rate = IQ Rate × FIR Interpolation × CIC Interpolation

Note  When the onboard signal processing is enabled by setting the OSP Enabled property or the NIFGEN_ATTR_OSP_ENABLED attribute, you cannot set the Sample Rate property or the NIFGEN_ATTR_ARB_SAMPLE_RATE attribute.