Active control of noise radiated from an x-ray tube

Abstract

The application of implementing an active noise control system to globally attenuate noise radiated from a medical x-ray tube has been investigated. The noise radiated from the x-ray tube is characterized by the presence of numerous tonal peaks distributed over a broad frequency bandwidth. Furthermore, there is sufficient variability in the radiated field that coherence in the acoustic field was also found to be a challenge. It was determined that a properly placed structural sensor could be used as a reference signal to achieve good coherence between the reference signal and error microphone. In order to achieve global control, speakers were placed in close proximity to areas that had been identified as source regions through the use of SLDV and acoustic intensity measurements. The frequency band below 1500 Hz was targeted, and it was found that effective attenuation could be achieved at over ten of the most prominent frequencies, resulting in attenuations in that bandwidth on the order of 7 dB. Some of ...