NIRFSG_ATTR_LO_PLL_FRACTIONAL_MODE_ENABLED
- Updated2025-05-22
- 1 minute(s) read
NIRFSG_ATTR_LO_PLL_FRACTIONAL_MODE_ENABLED
| Numeric Value | Data type |
Access | Coercion | High Level Functions |
|---|---|---|---|---|
| 1150152 | ViInt32 | R/W | None | None |
Description
Specifies whether to use fractional mode for the local oscillator (LO) phase-locked loop (PLL). This attribute enables or disables fractional frequency tuning in the LO. Fractional mode provides a finer frequency step resolution and allows smaller values for the NIRFSG_ATTR_LO_FREQUENCY_STEP_SIZE attribute. However, fractional mode may introduce non-harmonic spurs.
This attribute applies only if you set the NIRFSG_ATTR_LO_SOURCE attribute to NIRFSG_VAL_LO_SOURCE_ONBOARD_STR.
To use this attribute for the PXIe-5830/5831/5832, you must use the channelName parameter of the niRFSG_SetAttributeViInt32 function to specify the name of the channel you are configuring. You can configure the LO1 and LO2 channels by using lo1 or lo2 as the channel string, or set the channel string to lo1,lo2 to configure both channels. For all other devices, the the only valid value for the channel string is "" (empty string).
 |
Note For the PXIe-5841 with PXIe-5655, this attribute is ignored if the PXIe-5655 is used as the LO source. |
Defined Values:
| NIRFSG_VAL_ENABLE | Enables fractional mode for the LO PLL. |
| NIRFSG_VAL_DISABLE | Disables fractional mode for the LO PLL. |
Default Value: NIRFSG_VAL_ENABLE
Supported Devices: PXIe-5644/5645/5646, PXIe-5830/5831/5832/5840/5841/5842
Related Topics
Refer to the local oscillators topic appropriate to your device for more information about using fractional mode.