On the sampling frequency characteristics of the passive radio frequency vibration sensing tags in electromagnetic interference environments

Abstract The vibration sensing technology based on passive radio frequency (PRF) tags is a promising non-contact vibration monitoring method. To improve its vibration measurement performance and practicality necessitates ensuring a limited sampling frequency. Nonetheless, current research primarily focuses on the influence of electromagnetic interference on sensing accuracy, while neglecting its effect on the sampling frequency. Firstly, based on PRF vibration sensing tags, the significant impact of electromagnetic interference sources on the sampling frequency is investigated. It is found that electromagnetic interference notably reduces the sampling frequency, even leading to the tags being unrecognizable. Furthermore, the influence of electromagnetic interference on the tag sampling frequency is studied by varying the motor interference conditions and quantifying the corresponding electromagnetic intensity. Subsequently, the fundamental reason for the significant reduction in sampling frequency is thoroughly investigated by simultaneously analyzing the characteristics of the link layer and the communication protocol layer. By analyzing the amplitude domain and timestamp information of the received signal strength indicator signals, it is found that electromagnetic interference reduces the efficiency of PRF vibration sensing tags in energy acquisition and introduces timing errors in information transmission. It triggers a retransmission mechanism, ultimately leading to a significant decrease in sampling frequency.