Historically, the development of NVH sensors for automotive applications did not take into account the high-voltage (HV) electromagnetic (EM) fields now commonly present in electric and hybrid electric vehicles (EVs and HEVs). This has raised concerns about the potential impact of HV EM fields on microphone and accelerometer signals during operational testing.

To investigate these effects, a study was conducted on an EV to assess how HV EM fields influence NVH sensor performance. Ten different PCB NVH sensor models were evaluated, some with multiple cable configurations, positioned near various sources of HV EM fields within the vehicle. Sensor outputs were recorded alongside signals from nearby transducers specifically designed to measure EM field strength.

The degree of influence was quantified using the coherence function between each NVH sensor signal and its corresponding EM field measurement. Higher coherence values indicated a stronger correlation—and therefore a greater susceptibility—of the sensor signal to electromagnetic interference.