32. An analysis device comprising: a plurality of sensors for receiving a signal segment; a codebook configured to store parameters corresponding to a plurality of hypothesized power spectral density functions; a discriminant function calculation component configured to evaluate a likelihood of the hypothesized power spectral density function corresponding to the signal segment based on application of a discriminant function evaluated using a preconditioned conjugate gradient (PCG) process configured for block Toeplitz type matrices with a block size corresponding to the number of sensors; and a prior probability table configured to store prior conditional probabilities relating to the hypothesized power spectral density functions, wherein the discriminant function calculation component evaluates the likelihood of the hypothesized power spectral density functions corresponding to the signal segment based additionally on the prior conditional probabilities.
32. An analysis device comprising: a plurality of sensors for receiving a signal segment; a codebook configured to store parameters corresponding to a plurality of hypothesized power spectral density functions; a discriminant function calculation component configured to evaluate a likelihood of the hypothesized power spectral density function corresponding to the signal segment based on application of a discriminant function evaluated using a preconditioned conjugate gradient (PCG) process configured for block Toeplitz type matrices with a block size corresponding to the number of sensors; and a prior probability table configured to store prior conditional probabilities relating to the hypothesized power spectral density functions, wherein the discriminant function calculation component evaluates the likelihood of the hypothesized power spectral density functions corresponding to the signal segment based additionally on the prior conditional probabilities. 35. The device of claim 32 , wherein the prior probability table stores prior conditional probabilities of first speech spectral envelopes following second speech spectral envelopes, and wherein the discriminate function calculation component evaluates the likelihood of the hypothesized power spectral density functions corresponding to the sampled signal segment based on the conditional probabilities of the first speech spectral envelopes following the second speech spectral envelopes.