Application of microphone array for speech coding in noisy environment

To improve speech intelligibility and quality for coding, an array preprocessor is proposed to enhance noisy speech. The microphone array data is processed with a robust quadratically and linearly constrained minimum variance algorithm. The processor nulls noise and/or interference power from arbitrary spatial and frequency locations and maintains speech from desired locations, thus increasing the SNR for subsequent coding. The array and coder (LPC-10, CELP) structure is studied in terms of array processing gain and overall spectral distortion measurement. Preliminary results show that the array gain is transparent to CELP but not necessarily to LPC-10.