Abstract
A new method similar to the stroboscopic observation for measuring the impulse response of linear system was applied to sonic systems. The method essentially makes use of a peculiar periodic property of the autocorrelation function of a signal derived from a maximal-length binary shift register sequence which is applied to the input. A quick impulse response can thus be recorded directly on a rather slow pen writing oscillograph with the scale of time magnified by a factor of several thousands.
The value of sound velocity measured from the recorded impulse response of the sonic system, which was formed with a speaker and a microphone, agreed with that at the room temperature. The distance to a wall was also measured from the impulse response caused by the sound wave reflected at the wall surface.
