How to select a vocoder algorithm?
TOP When selecting a vocoder algorithm there are several criteria to consider: ” Interoperability: In order to ensure interoperability in telecommunication systems, standard algorithms are defined. For example, the ITU G.723.1 and G.729A standard coders are commonly adopted by the ITG developers. When interoperability is not required, as in the case for voice mail, proprietary algorithms are often preferred. ” Digital Bandwidth: Most 8 KHz voice compresion algorithms compress signals down to 2.4~64Kbps. The popular G.729A algorithm compresses 8 KHz speech down to 8 Kbps, providing eight voice channels on a single 64 Kbps T1, E1 or ISDN line. ” Voice Quality: The speech quality degrades as the bit rate decreases. The analog bandwidth supported by a vocoder also directly affects its speech quality. There are industry standard measures for vocoder quality called Mean Opinion Score (MOS), Diagnostic Acceptability Measure (DAM), and Dynamic Rhyme Test (DRT). These measures are most useful w
