904 the receiving means 901 and channel decoding means 902 together perform equalisation detection and channel decoding the purpose of which is to convert received electromagnetic radiation into an as reliable copy as possible of what the channel encoder received from the source encoder in a transmitting device the task of the source decoding means 903 is to reverse the effect of source encoding so that after source decoding the resulting audio signal can be delivered to the sound reproducing means 904 for conversion into acoustic waves control means 905 are provided to control the operation of the functional blocks of the reception chain in accordance with the presented embodiment of the invention the source decoding means 903 comprise bit stream demultiplexing means 911 low band decoding means 912 low band excitation signal extracting means 913 excitation selection checking means 914 additional excitation signal generating means 915 excitation selecting means 916 high band decoding means 917 and band reconstructing means 918 of these the bit stream demultiplexing means 911 are arranged to demultiplex the received bit stream and to direct the appropriate portions thereof to the low band decoding means 912 the excitation selection checking means 914 and the high band decoding means 917 the low band decoding means 912 are arranged to perform standard lpc decoding for the low band audio signal and to deliver decoding results to the band reconstructing means 918 the low band decoding means 912 also deliver the low band excitation signal through certain conceptually defined low band excitation extracting means 913 which also include resampling if any is required to the excitation selecting means 916 the.