Test signals used in electroacoustics and speech technology

The presentation consists of two parts. In the first one, the typical signals applied for testing of electro-acoustical devices are presented. These signals are e.g: harmonic signal, slowly and quickly tuned sinusoid, impulses, Gaussian noise, Maximum Length Sequence, Golay's Complementary Sequences. The statistical and spectral properties of these signals are described. The methods of analysis of stationary and nonstationary signals are presented as well. In the second part, the signals used for the evaluation of quality of coded and transmitted speech are presented. For this aim, the natural or artificial speech signals are used. The test material can consist of units having semantic meaning as well as of nonsense syllables or words. For the Polish language, the Polish Standard provides a set of logatome lists. American ANSI norms include, among others, rhyme tests. The International Telecommunication Union (ITU-T) guidelines specify the requirements for the test signal base for telecommunications applications. This recommendation presents a set of test signals of various complexity with many typical speech parameters. These signals are intended for both subjective and objective evaluation of the quality of speech transmission.