Method and apparatus for measuring the quality of speech transmissions that use speech compression

An apparatus for determining quality of a speech transmission processed by a speech transmission system comprising:

• a processor coupled to the speech transmission system;
• a memory coupled to the processor to store the speech transmission;
• wherein the processor
• stores an output signal from the speech transmission system;
• compares the output signal to a reference signal, wherein the reference signal is a signal resulting from processing a test signal with a codec that uses an algorithm for coding that is the same as an algorithm used for coding in the speech transmission system;
• wherein the test signal comprises:
• a plurality of segments of speech signals interleaved with a plurality of periods of silence, wherein between adjacent segments of the plurality of segments there is a period of silence of the plurality of periods of silence;
• wherein each segment of the plurality of segments comprises a plurality of speech samples interleaved with a plurality of silence gaps, wherein there is a silence gap of the plurality of silence gaps between adjacent speech samples of the plurality of speech samples, wherein each speech sample of the plurality of speech samples has a first predefined duration;
• wherein the plurality of silence gaps do not all have a same duration;
• wherein the plurality of periods of silence do not all have a same duration;
• and
• wherein the first predefined duration is a function of a packet size associated with the speech transmission system.

A method for determining the quality of a speech transmission processed by a speech transmission system, the method of comprising the steps of:

• transmitting the test signal through the speech transmission system, wherein the speech transmission system includes a vocoder and wherein the speech transmission system uses the vocoder to create an output signal that corresponds to the test signal as modified by the speech transmission system;
• wherein the test signal comprises:
• a plurality of segments of speech signals interleaved with a plurality of periods of silence, wherein between adjacent segments of the plurality of segments there is a period of silence of the plurality of periods of silence;
• wherein each segment of the plurality of segments comprises a plurality of speech samples interleaved with a plurality of silence gaps, wherein there is a silence gap of the plurality of silence gaps between adjacent speech samples of the plurality of speech samples, wherein each speech sample of the plurality of speech samples has a predefined duration;
• wherein the plurality of silence gaps do not all have a same duration;
• and
• wherein the plurality of periods of silence do not all have a same duration;
• and
• wherein the predefined duration is a function of a packet size associated with the speech transmission system.