Why the LO2 Frequency Range of PXIe-5830 is only up to 7.1GHz

Updated Nov 7, 2022

Reported In

Hardware

  • PXIe-5833
  • PXIe-5831
  • PXIe-5832

Issue Details

When we look at the Specification document of PXIe-5830/PXIe-5831, we will find the following introduction about LO2:
5830 LO2 spec part.jpg

From the above content, we can see that LO2 only supports the frequency band 3.55GHz~7.1GHz, but our PXIe-5830 needs to support 5GHz~12GHz. We all know that PXIe-5830/31 is a zero-IF architecture, which requires LO Resource to provide 5GHz~12GHz signal to be mixed to generate 0Hz IF signal. So we have the question, how does LO2 work?

Solution

The IF Module hardware design block diagram of PXIe-5830 is as follows:
5830 LO2 diagram.jpg

we can see that although the LO2 source can only output 3.55GHz~7.1GHz, there is a frequency doubling conversion (X2 is double the frequency) in the circuit design, which can meet the needs of frequency mixing.