Kõnekodeerijate

Kõnekodeerijate, commonly known as speech coders or vocoders, are algorithms or devices that compress and encode human speech. Their primary purpose is to reduce the amount of data required to represent speech signals for transmission or storage, making efficient use of bandwidth and storage space. This is particularly important in telecommunications, where transmitting voice over limited channels is crucial.

Speech coders achieve compression by exploiting redundancies and characteristics specific to human speech. They typically work by analyzing the speech signal in short segments, often called frames, and extracting key features. These features can include parameters related to the pitch, loudness, and spectral envelope of the speech. Instead of transmitting the raw audio waveform, the coder transmits these extracted parameters. At the receiving end, a speech decoder uses these parameters to synthesize an approximation of the original speech.

There are various types of speech coders, broadly categorized into waveform coders, parametric coders, and hybrid coders. Waveform coders aim to reproduce the speech waveform as accurately as possible, while parametric coders focus on modeling the vocal tract and excitation source. Hybrid coders combine elements of both approaches. The choice of coder depends on the desired trade-off between speech quality, compression ratio, and computational complexity. Higher compression ratios generally lead to lower speech quality, and vice versa. Modern speech coding techniques are essential for applications like mobile telephony, voice over IP (VoIP), and audio compression for broadcasting.