Abstract
An adaptive transform coder is proposed that makes effective use of vector quantization. It is aimed at medium-band (4. 8-9. 6 kbps) speech coding. In order to minimize waveform distortion, DFT (discrete Fourier transform) components of the LPC (linear predictive coding) residue are quantized using two novel techniques: bit allocation to blockwise DFT components has been made adaptible to obtain snr gain, and quantization has been divided into two stages (vector-scalar) for higher bit rates. Subjective quality of speech coded at 7. 2 kbps is comparable to that for 5 bit log-PCM. Intelligibility tests show that the coder is resistant to background noise.
| Original language | English |
|---|---|
| Pages (from-to) | 435-445 |
| Number of pages | 11 |
| Journal | Denki Tsushin Kenkyujo kenkyu jitsuyoka hokoku |
| Volume | 34 |
| Issue number | 3 |
| Publication status | Published - 1985 |
| Externally published | Yes |
ASJC Scopus subject areas
- Engineering(all)