The accompanying website (www.cambridge.org/9780521855952) contains audio illustrations of various aspects discussed in the book. These examples are presented in the wav format; they may be listened to on a personal computer with Microsoft Windows Media Player, RealPlayer, or other audio programs that play the wav format. Specialized programs such as Cooledit are best suited for the demonstrations. They offer an audiovisual experience and the ability to analyze and manipulate the signal.

The audio illustrations are divided into the following groups:

• Codec illustrations, where the same speech segment is played through a variety of particular codecs.

• Hybrid echo, where the same speech segment produces echo as a function of delay and ERL combinations.

• Various recordings of noise types, including different crowd noises, wind, seashore, busy street, and white noise.

• Acoustic-echo control under noisy conditions with different comfort-noise matching.

• Recordings that demonstrate the “before” and “after” VQS processing of a conversation taking place under noisy conditions.

• Examples related to cases discussed in Chapter 12.

• DTMF and ring-back tones.

The intent of the audio illustrations is to highlight certain elements that can be better depicted by having them listened to. They can also serve as raw material for those who wish to use the demos in their own presentations and test platforms.

Codec illustrations

The codec illustrations on the website are all produced without background noise or transmission errors.