Abstract: Successive pitch periods/frequencies are accurately determined in an audio equivalent signal. Using a suitable conventional pitch detection technique, an initial value of the pitch frequency/period is determined for so-called pitch detection segments of the audio equivalent signal. Based on the determined initial value, a refined value of the pitch frequency/period is determined. To this end, the signal is divided into a sequence of pitch refinement segments. Each pitch refinement segment is associated with at least one of the pitch detection segments. The pitch refinement segments are filtered to extract a frequency component with a frequency substantially corresponding to an initially determined pitch frequency of an associated pitch detection segment. The successive pitch periods/frequencies are determined in the filtered signal.

Abstract: An audio equivalent signal is coded by determining a noise value for harmonic frequencies. The noise value is determined by the change of phase of the harmonics in successive segments of the signal. The noise value for a harmonic frequency represents a contribution of a periodic component and an aperiodic component to the segment at the harmonic frequency. To this end, the pitch development of the signal is determined, and the signal is broken into segments of, e.g., one or two pitch periods wide. For each of the analysis segments an amplitude value and a phase value is determined for the harmonic frequencies. The noise value for each of the harmonics is determined by comparing the phase value for the harmonic of the segment to a corresponding phase value for at least one preceding or following segment. Each segment is coded as the amplitude value and the noise value for each of the harmonics. The method is preferably used for speech synthesis.

Abstract: An audio equivalent input signal is divided into a sequence of overlapping or adjacent signal segments. A lengthened signal is synthesized by systematically maintaining or repeating respective signal segments of the sequence of segments. Repeating non-periodic segments, such as a voiceless part of a speech signal or noise in music, results in audible artefacts. The introduced periodicity is broken by dividing a signal section originating from one non-periodic source signal segment into a second sequence of signal segments with at least one of the signal segments having a duration not equal to a duration of the source signal segment and not equal to a multiple of the duration of the source signal segment. Signal segments of the second sequence are shuffled.

Abstract: Speech is received as a sequence of segments that are coded according to an LPC principle. The segments are reproduced for concatenated read-out in audio reproduction, by exciting an all-pole filter with recurrent signals in case of voiced speech and by white noise in case of unvoiced speech. In particular, the recurrent signals are globally represented as an accumulated series of periodic signals on the basis of mutually overlapping time windows. The recurrent signals are supplemented by noise for filtering through an amended LPC filter derived from the original LPC-filter by using information of pitch and formants, and of a voiced-unvoiced dichotomy. The filter is determined as depending on at least a subset of the four quantities Global Noise Scaling, Pitch Dependent Noise Scaling, Amplitude Dependent Noise Scaling, and Inter-Formant Noise Scaling.