The concept of noise-to-signal ratio improvement for the photo-acoustic technique in pulse modulation mode

In this paper the authors concern the problem of determination of thermal properties of the object realized basing upon the results of photoacoustic measurements in pulse modulation mode. Due to high dependency of broad-band signal upon the parameters of experimental setup and very low noise-to-signal ratio of the signal, such an analysis can be done only in the frequency domain basing upon contrast frequency characteristics. The authors see at least two necessary conditions of correctness of such an analysis, which are as following: 1) the reduction of the influence of linear distortions on measured values, 2) lack of non-linear distortions.