Abstract: A method of transmitting and receiving coded speech, in which method samples are taken of a speech signal and reflection coefficients are calculated from these samples.

Abstract: A transcoding and transdecoding unit in a digital mobile radio system, and methods for adjusting their output signals. The unit includes an expander for converting companded digital data into a linear signal; a speech encoder for coding a linearized signal into encoded form; and an amplifier for amplifying the expanded signal. In order that the outbound audio signal not suffer interference due to the raised level, the transcoding unit further includes a level monitor for monitoring the amplitude of the linearized signal and for controlling amplifier such that the signal produced by the amplifier is of a desired level.

Abstract: A method of converting speech, in which reflection coefficients are calculated from a speech signal of a speaker. From these coefficients, characteristics of cross-sectional areas of cylinder portions of a lossless tube modelling the speaker's vocal tract are calculated. Sounds are identified from those characteristics of the speaker and provided with respective identifiers.

Abstract: A speaker recognition method, including comparing a model calculated on the basis of samples derived from a speech signal with a stored model of at least one known speaker. The averages of the cross-sectional areas or other cross-sectional dimensions of portions (C1-C8) of a lossless tube model of the speaker's vocal tract, calculated by means of the samples derived from the speech signal, are compared with the corresponding averages of the portions of the stored vocal tract model of at least one known speaker.