Patent ID: 8566082

Claim:
A method for determining a speech quality measure of an output speech signal with respect to an input speech signal, wherein the input signal passes through a signal path of a data transmission system resulting in the output signal, the method comprising the steps of: pre-processing the output signal; determining a discrete frequency spectrum of the pre-processed output signal within a pre-defined time interval, wherein the discrete frequency spectrum comprises spectral amplitude values for frequency/time pairs based on a pre-defined sampling rate and a number of pre-defined frequency bands; detecting interruptions in the pre-processed output signals so as to determine an interruption rate, wherein the detecting includes determining a gradient of the discrete frequency, wherein the start of an interruption is identified by a gradient which lies below a first threshold, and the end of the interruption is identified by a gradient which lies above a second threshold; detecting musical tones so as to determine a measure for intensity of musical tones, wherein the detecting includes determining an expected amplitude value for each frequency-time pair and determining frequency/time pairs for which the spectral amplitude value is higher than the expected amplitude value and a difference between the spectral amplitude value and the expected amplitude value exceeds a pre-defined threshold; and determining the speech quality measure by calculating a combination of the interruption rate and the measure for intensity of musical tones.