WIDEBAND SPEECH CODING

Higher bandwidths than that of the 300 to 3400 Hz telephone bandwidth result in major subjective improvements in represented speech quality [3, 4]. A bandwidth of 50 to 7000 Hz not only improves the intelligibility and naturalness of speech, but adds also a feeling of transparent communication and eases speaker recognition. Application areas of wideband speech include [2]

1. Audio and video teleconferencing where broadened bandwidth(50-7000 Hz) provides improved sound quality,more presence of the speaker, and a more realistic rendering of the actual sound in a room.
2. Digital AM radio broadcasting where the 50-7000 Hz band is currently used for high-quality voice transmission.
3. High-fidelity telephony where broadcast quality voice is transmitted over cables, fiber optic networks or even the local loop(after modification to eliminate the current band-limiting networks).
4. Dual language programming in audio and audio/video broadcasts of news, TV programs, closed circuit lectures, etc.

• The CCITT G.722 Wideband Speech Coding Standard
  • Subjective Performance
• Low-delay CELP coding of 7kHz speech at 32 kbit/s
  • Perceptual Noise Weighting
  • Subjective Performance
• Other Wideband Speech Coding Techniques