Hello,

I have some issues when testing an automotive device using a CDN on power supply cables (both BAT+ and BAT-/GND). Device is powered from car's battery.

The noise on BAT-/GND is affecting the measurements (incoming signal pulses from other external devices) and the results are not accepted. Any filter on incoming signal is not working due to the noise on GND.

I have read many articles about filtering (common mode chokes, LC filters etc) but nothing solved our issue yet.

I would be obliged if someone had encountered similar problems on a final device and shares his experience.

 

I am attaching an image which shows the test configuration:

 

Is this battery disconnected from the vehicle? If not, what type of vehicle are you using? Does the noise femain after everything in the car has powered down? What is the EUT you are testing? ECM, BCM, IC???