Measurement of acoustic parameters by means of pseudorandom signals

In this paper, a portable acoustic parameter analyser is presented. Based on pseudorandom sequences, the analyser obtains the impulse response of a linear system using the cross-correlation between the pseudorandom input sequence and the output signal of the system to be measured. The deterministic nature of the pseudorandom sequence allows one to achieve high dynamic range measurements with very low amplitude signals. Once the impulse response signal, h(t), is obtained, the acoustic parameters are calculated. The main advantage of the analyser relies on its ability to work under noisy situations, something vital in acoustics because the acoustic properties of a room constantly alters. Measurements can be made without interfering room activities such as plays or music concerts.