中文摘要：

利用可控脉冲声信号，采用回波方法，在圆形声管中测量了样本材料的吸声系数。依据回波信号和入射声波的功率谱密度先解算反射系数，然后计算吸声系数。与B＆K4206阻抗管测量结果相比，在200Hz～5kHz频段内吸声系数差别在10％以内。所用脉冲声具有波形规则、脉冲时间短、频带宽的特点，测量精度比同类方法显著提高，特别是低频区域数据可靠。测量系统装置简单、重复性好。测量装置的不确定度主要源于样品在声管中安装的精密性。

英文摘要：

Two different waveforms referred as to Butterworth and damped sine are successfully generated and used as incident pulse in the experiment of sound absorption measurement in a circular pipe with echo-pulse method. The absorption coefficient is solved from the reflection coefficient which is calculated from the ratio of power spectral densities of reflection pulse and incident pulse. The absorption coefficient measured by the echo-pulse method is consistent to the result of B＆K 4206 impedance tube measurement. Difference of the sound absorption coefficient between the above mentioned methods is generally less than 10% in broad frequency range from 200 Hz to 5 kHz. Since the generated sound pulse are with the features of regular waveform, short duration and broadband frequency spectrum, the proposed method has fairly accurate result in sound absorption measurement and is with the advantage of reducing low-frequency cutoff which is an inherent limitation in impedance tube. Equipment of the proposed method is relative simple and is with good repetition. The measurement error is mainly due to the inaccurate installation of the material in pipe.