Abstract: The choise of pure tone or noise as signal source in the measurement of free field deviation of anechoic or semi-anechoic room will affect the results of measurements. By using anechoic room free field deviation model in first-order reflection condition, the difference of the results measured by the two kind of signal was deduced. Through comparison, the deviation law  of free field are obtained, which verifies the analytical model used and gives a good reference for the choice of signal source in free field measurements.

Key words: acoustics , deviation of free field , inverse square attenuation rate , first order reflection of sound field

摘要： 消声室和半消声室的自由声场偏差测量时，选择纯音信号或者噪声信号作为测量用的信号源，会对测量结果产生影响。通过消声室自由声场1阶反射条件下的自由声场偏差推论模型，推理出两种信号测量结果的差异。通过使用纯音信号和噪声信号对消声室和半消声室的自由声场偏差进行测量，并比较两种信号测得的结果的差异，得出实操层面使用两种信号测得的偏差规律，验证模型推理，并对消声室和半消声室的自由声场测量时的信号源选择提供参考。

关键词: 声学, 自由声场偏差, 反平方率衰减, 声场1阶反射