Abstract: Code-excited linear prediction speech encoders/decoders with excitation including an algebraic codebook contribution encoded with a single sign bit for each track of pulses by inferring pulse amplitude signs from the pulse position code ordering within a codeword.

Abstract: A process for noise reduction during the transmission of acoustic useful signals includes the following steps of: (a) determining when a speech pause is present; (b) branching the incoming TC signal from the main signal path and utilizing a Fourier transformation to generate a frequency spectrum; (c) storing in a buffer memory (3) the last frequency spectrum recorded during the last speech pause; (d) using an inverse Fourier transformation on the respective last recorded frequency spectrum to generate a simulated noise signal; (e) subtracting the simulated noise signal in the time domain from the current incoming TC signal. As a result, the original signal is maintained uncorrupted up to the actual noise subtraction. With a simple arrangement and less computing effort than before, the process enables an overall acoustic impression to be produced, which is as agreeable as possible to the human ear and which can be matched to individual requirements.