Patent ID: 7233897

Claim:
A method of performing Frame Erasure Concealment (FEC) for a speech coder that does not have FEC capability, comprising: receiving encoded frames of compressed speech information transmitted from an encoder; determining if an encoded frame is erased, lost or corrupted in transmission, decoding the received encoded frames into decoded frames if the determining step determines that the encoded frame is not erased; generating a synthetic frame for the erased frame using data of previously decoded frames if the determining step determines that the encoded frame is erased; updating a first memory with data of the decoded and synthetic frames; and outputting the decoded and synthetic frames as audio signals wherein the generating step at the first erased frame in a sequence of one or more erased frames comprises: estimating a pitch period of the erased frame; copying one or more of most recent pitch periods from the first memory to a second memory; copying a portion of the most recent pitch period from the first memory to a third memory; overlap adding the third memory with a portion of a pitch period stored in the second memory; storing the overlap added portion of the pitch period in the most recent portion the second memory; generating a synthetic frame based on one or more of the most recent pitch periods stored in the second memory, for updating the first memory in the updating step and output in the outputting step; and storing in an offset pointer the last location in the second memory used in the generating step.