提出了一种声屏障声影区与声亮区过渡区域的绕射衰减室外测量方法.方法采用5ms的正弦波作为测试信号,利用声波到达时间的差异有效地排除地面反射和有限长声屏障两侧绕射的影响,并通过背景噪声频谱分析选取测试声以及对接受信号FIR滤波以最大限度降低背景噪声的影响,同时考虑了气象条件变化导致的大气衰减修正.为进一步验证方法有效性,选取直立声屏障作为试验案例.结果表明,与室内全消声室试验结果、几何绕射理论结果接近,试验精度高.%To research the diffraction attenuation of sound barrier in the transitional zone of shadow region to bright region, anrnoutdoor measurement method was proposed. 5ms-long pure sine waves were used for test signals. It can be effectively eliminatedrnthe effects of ground reflection, diffraction from two limited edges and meteorological condition changes by considering tinyrndifferences among received signals. Background noise was analyzed before measurement to select suitable test signals, and FIRrnfilter was processed for ruling out other frequency's influence. To validate the efficiency of proposed method, a thin barrier wasrnchosen for illustration. Results show that experimental data accurately reflects the anechoic chamber and geometrical theory ofrndiffraction ones.
展开▼
