EM7565 GNSS RF Receive Path Test Negative Frequency Return

We have some functional test stations which are validating units of ours that utilize the EM7565. As part of the validation we perform the GNSS RF Receive Path Test as specified in the AirPrime EM7565 Product Technical Specification. Occassionally we get have been getting a return for the frequency which is negative (typically around -422500), which causes the test to fail. Other measurements are in the expected range (we take 5 measurements). When we retest those units, it will usually pass the second or third time around.

Any insight as to why this could be occurring would be greatly appreciated - mostly want to understand if this is a potential FW bug that should be ignored, or if it indicates potential HW issues.

Thank you for your time!

did you test in the Sierra development kit?
Is the module OK to receive GPS signal in real environment?
Are you using latest FW?

Hello,

No, this is in a custom design, we have not run the GNSS test in the dev kit.

Yes GPS has worked with our design, we usually have it disabled though.

Modules are being regularly ordered new for produced units so I would assume they have the latest FW.

Thank you

what is the firmware version in “ati3”?

I’ll try to get that on one of the newer units going through, at the moment I only have access to some that were produced over a year ago.

Is there any idea as to what a negative frequency would indicate?

no , i have no idea, maybe some measuring equipment problem