The effect of environmental noise on sound signal frequency discrimination
Liang Zhenfu · 2001
Objective Experiment of the effect of environmental noise on different sound signal frequency discrimination threshold in human subjects was carried out with the aim of finding a specific anti-noise signal so as to provide theoretical basis of developing an anti-noise speech communication device. Methods Theree kinds of modulating sound waves including frequency modulating pure tone signal (f) .amplitude and frequency modulating signal (fam) and frequency modulating square wave signal (fr) were used. Adopting over threshold value measurements and taking discrimination values above threshold 40 dB as normal control.the signal/noise(S/N) frequency discrimination values of 0, ?5 and ?10 were measured respectively. Results The best frequency discrimination signal of the three was square wave with amplitude modulating wave second and pure tone wave third. Conclusions This experiment opened a new way of anti-noise speech communication. With square wave or amplitude modulating wave transmission,the speech communication will have satisfactory intelligibility.