Patent ID: 7480615

Claim:
A method of setting posterior probability means for posterior probability distributions in a switching state space model, the posterior probability providing the likelihood of a set of hidden states for a sequence of frames based upon input values associated with the sequence of frames, the method comprising: inputting a speech signal identifying input values of a sequence of frames from the speech signal defining a window containing at least two but fewer than all of the frames in the sequence of frames; determining a separate posterior probability mean for each frame in the window each posterior probability mean providing a mean value for a continuous hidden state given at least an input value wherein determining a separate posterior probability mean for each frame further comprises determining a separate posterior probability mean: for each of a set of discrete hidden states that are different from the continuous hidden states: shifting the window so that it includes at least one subsequent frame in the sequence of frames to form a shifted window; and determining a separate posterior probability mean for each frame in the shifted window; and using the posterior probability means to decode a speech signal.