NI 5442
Using an External Clock with the OSP Block

Some applications may require lower jitter or phase noise than the onboard High-Resolution clock. You can use an external clock source to achieve spectral purity at any arbitrary IQ rate. To determine the frequency of the sample rate for the external clock source, complete the following steps.

1. Set the Sample Clock Source property or the NIFGEN_ATTR_UPDATE_CLOCK_SOURCE attribute to the external clock source you are using.
2. Set the IQ Rate property or the NIFGEN_ATTR_OSP_IQ_RATE attribute.
3. Read the value of the Sample Rate property or the NIFGEN_ATTR_ARB_SAMPLE_RATE attribute.
4. Set the external clock source sample rate to the frequency of the Sample Rate property or the NIFGEN_ATTR_ARB_SAMPLE_RATE attribute that you just read.
5. Validate that the external Sample clock source is connected to the NI 5442 connector specified in the Sample Clock Source property or the NIFGEN_ATTR_SAMPLE_CLOCK_SOURCE attribute and is generating a clock before you continue configuring the NI 5442.

For more information about using external clocks with the NI 5442, refer to External Sample Clock Sources.