The Study on Scattering Coefficient Measurement Using a “Spark Train” in a Scaled Reverberation Room

Abstract

Full-size reverberation chamber random-incidence scattering coefficient measurements are often complex and time-consuming, making scaled reverberation chamber systems a preferred alternative for improving efficiency. Conventionally, scaled measurements employ a high-frequency impulse source combined with a stepwise rotating turntable. In this approach, 72 impulse responses are recorded at 5° increments and averaged to obtain the specular reflected impulse response. However, for asymmetric specimens, scattering characteristics vary at each angle, and relying solely on fixed angular responses neglects other directional properties. In this study, a “spark train” sound source was introduced to measure scattering coefficients in a 1:10 scaled reverberation chamber using a continuous rotation approach. A high-frequency impulse source was coupled with a continuously rotating turntable. Once the impulse was emitted, the turntable rotated without interruption, and the reflected sound in the nonlinear impulse response represented an integration of scattering contributions from multiple angles. Experimental results demonstrated that the scattering coefficients obtained with this method align more closely with full-scale measurements based on MLS signals. In addition, the effects of turntable rotation status, source emission interval, air absorption correction methods and test specimen sampling geometry on the accuracy of measured scattering coefficients were analyzed in detail.