NIRFSA_ATTR_IF_OUTPUT_FREQUENCY
- Updated2024-05-08
- 1 minute(s) read
NIRFSA_ATTR_IF_OUTPUT_FREQUENCY
Specific Attribute
| Data type |
Access | High Level Functions |
|---|---|---|
| ViReal64 | RO | None |
Description
Returns the center frequency of the IF output signal that corresponds to the configured RF center frequency.
The downconverter translates the RF input frequency to the IF output frequency by mixing it with the LO signal. The nominal values for the IF output frequency are shown in the following table.
| Downconverter | Nominal IF Output Frequency |
|---|---|
| PXI-5600 | 15 MHz |
| PXIe-5601 | 53 MHz or 187.5 MHz |
| PXIe-5603 | 187.5 MHz or 199 MHz |
| PXIe-5605 | 187.5 MHz, 190 MHz, or 199 MHz |
| PXIe-5606 | 187.5 MHz, 190 MHz, 199 MHz, 507.5 MHz, or 730 MHz |
| PXIe-5694 | NIRFSA_ATTR_SIGNAL_CONDITIONING_ENABLED set to NIRFSA_VAL_SIGNAL_CONDITIONING_ENABLED and NIRFSA_ATTR_IF_CONDITIONING_DOWN_CONVERSION_ENABLED set to NIRFSA_VAL_DISABLED: 193.6 MHz NIRFSA_ATTR_IF_CONDITIONING_DOWN_CONVERSION_ENABLED set to NIRFSA_VAL_ENABLED: 21.4 MHz NIRFSA_ATTR_SIGNAL_CONDITIONING_ENABLED set to NIRFSA_VAL_SIGNAL_CONDITIONING_BYPASSED: 162.5 MHz to 212.5 MHz |
The coarse nature of the LO settings can cause the downconverter to be unable to tune to the exact LO frequency that would produce the nominal IF output frequency. Any coercion in the actual LO frequency results in the IF output frequency being slightly off from the nominal value.
Additionally, if you use the NIRFSA_ATTR_DOWNCONVERTER_CENTER_FREQUENCY and NIRFSA_ATTR_LO_FREQUENCY attributes to program the downconverter, the IF output frequency could vary from the nominal value. NI-RFSA adjusts the acquired spectrum or I/Q data for the difference between nominal and actual IF output frequency. If you use an external digitizer with a RF downconverter, use this attribute to specify the actual IF output frequency.
Default Value: N/A
Supported Devices:PXI-5600, PXIe-5601/5603/5605/5606 (external digitizer mode), PXI-5661, PXIe-5663/5663E/5665/5667/5668, PXIe-5694