niRFSA_ConfigureIQRate
- Updated2025-02-03
- 3 minute(s) read
niRFSA_ConfigureIQRate
ViStatus niRFSA_ConfigureIQRate(ViSession vi, ViConstString channelList, ViReal64 iqRate);
Purpose
Specifies the I/Q rate for the acquisition. The value is expressed in samples per second (S/s).
For the PXIe-5663/5663E/5665/5667/5668, when you set the NIRFSA_ATTR_DIGITIZER_SAMPLE_CLOCK_TIMEBASE_SOURCE attribute to NIRFSA_VAL_ONBOARD_CLOCK_STR, the digitizer bandwidth is greater than or equal to the coerced iqRate times 0.8. Actual signal bandwidth is limited for all supported devices by the anti-aliasing filter. Further device-specific limitations are as follows.
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Note For the PXIe-5663/5663E/5665/5667/5668, NI-RFSA enables dithering by default. The dither noise can appear in your passband and affect your measurements. Refer to the NIRFSA_ATTR_DIGITIZER_DITHER_ENABLED attribute for more information about dithering. |
- PXI-5661—You should not need to configure an iqRate higher than 25 megasamples per second (MS/s) because the PXI-5600 RF downconverter bandwidth is 20 MHz. If you configure a higher I/Q rate, you may see aliasing effects at negative frequencies because the IF frequency of the PXI-5600 RF downconverter is 15 MHz.
- PXIe-5663/5663E—Maximum allowed instantaneous bandwidth depends on the I/Q carrier frequency you use. Refer to the PXIe-5601 RF Downconverter Overview for more information about instantaneous bandwidth.
- PXIe-5665—Actual signal bandwidth is limited by the preselector and the combination of the chosen IF filter and anti-aliasing filter. Maximum allowed instantaneous bandwidth is independent of the downconverter center frequency for frequencies less than 3.6 GHz. At frequencies greater than 3.6 GHz, if your device supports the preselector (YIG-tuned filter) and you have enabled it for your application, the maximum allowed instantaneous bandwidth is limited to the instantaneous bandwidth of the preselector. Refer to the NI PXIe-5665 Specifications for more information about instantaneous bandwidth limits.
- PXIe-5667—Actual signal bandwidth is limited by the preselector and the combination of the chosen IF filter and anti-aliasing filter. Maximum allowed instantaneous bandwidth depends on the downconverter center frequency you use. Refer to the NI PXIe-5667 Specifications for more information about instantaneous bandwidth limits.
- PXIe-5668—Actual signal bandwidth is limited by the FPGA image that is downloaded upon opening the session to the PXIe-5624 digitizer. Maximum allowed instantaneous bandwidth depends on the downconverter center frequency you use. Refer to the PXIe-5668 Specifications for more information about instantaneous bandwidth limits.
- PXIe-5644/5645/5646, PXIe-5830/5831/5832/5840/5841/5842—Maximum allowed instantaneous bandwidth depends on the downconverter center frequency you use. Refer to the specifications document for your device for more information about instantaneous bandwidth limits.
Supported Devices: PXIe-5644/5645/5646, PXI-5661, PXIe-5663/5663E/5665/5667/5668, PXIe-5820/5830/5831/5832/5840/5841/5842/5860
Related Topics
Parameters
| Input | ||
| Name | Type | Description |
| vi | ViSession | Identifies your instrument session. vi is obtained from the niRFSA_init or niRFSA_InitWithOptions function. |
| channelList | ViConstString | Identifies which channels to apply settings. Specify an empty string as the value of this parameter. |
| iqRate | ViReal64 | Specifies the I/Q rate for the acquisition. The value is expressed in samples per second (S/s). |
Return Value
| Name | Type | Description | ||||||||
| status | ViStatus | 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 NI-RFSA 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 niRFSA_GetError function. To clear the error information from NI-RFSA, call the niRFSA_ClearError function. The general meaning of the status code is as follows:
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