Method and apparatus for coding successive pitch periods in speech signal

Claim 1

A method of coding a sound signal in a plurality of signal frames each having a pitch period indicative of the sound signal in the respective signal frame, wherein each signal frame comprises a plurality of signal segments each representing a dimension in a pitch space, and the sound signal in each of the signal segments is characterized by a pitch value, and wherein the pitch values are representable by a point distribution pattern characteristic of the sound signal in a lattice structure for defining codebook indices in the pitch space, said method comprising the steps of: shaping the lattice structure based on the point distribution pattern; and providing a codebook index representing the pitch value in each dimension of the pitch space according to the shaped lattice structure for facilitating coding of the sound signal.

Claim 2

A method of coding a sound signal in a plurality of signal frames each having a pitch period indicative of the sound signal in the respective signal frame, wherein each signal frame comprises a plurality of signal segments each representing a dimension in a pitch space, and the sound signal in each of the signal segments is characterized by a pitch value, and wherein the pitch values are representable by a point distribution pattern characteristic of the sound signal in a lattice structure for defining codebook indices in the pitch space, said method comprising the steps of: shaping the lattice structure based on the point distribution pattern; and providing a codebook index representing the pitch value in each dimension of the pitch space according to the shaped lattice structure for facilitating coding of the sound signal.

Claim 13

An apparatus for encoding a sound signal in a plurality of signal frames each having a pitch period indicative of the sound signal in the respective signal frame, wherein each signal frame comprises a plurality of signal segments each representing a dimension in a pitch space, and the sound signal in each of the signal segments is characterized by a pitch value, and wherein the pitch values are representable by a point distribution pattern characteristic of the sound signal in a lattice structure for defining codebook indices in the pitch space, and the lattice structure is shaped based on the point distribution pattern for defining a shaped lattice structure, said apparatus comprising: means, responsive to the sound signal, for obtaining an open-loop estimate of the pitch period by an open-loop search from the shaped lattice structure considering all of the dimensions of the pitch space for providing an open-loop search value indicative of the open-loop estimate; and means, responsive to the open-loop search value, for refining the open-loop estimate in each of the dimensions in the pitch space separately by a closed-loop search from the shaped lattice structure for obtaining a closed-loop search value indicative of the pitch value in the respective signal segment.

Claim 14

An apparatus for encoding a sound signal in a plurality of signal frames each having a pitch period indicative of the sound signal in the respective signal frame, wherein each signal frame comprises a plurality of signal segments each representing a dimension in a pitch space, and the sound signal in each of the signal segments is characterized by a pitch value, and wherein the pitch values are representable by a point distribution pattern characteristic of the sound signal in a lattice structure for defining codebook indices in the pitch space, and the lattice structure is shaped based on the point distribution pattern for defining a shaped lattice structure, said apparatus comprising: means, responsive to the sound signal, for obtaining an open-loop estimate of the pitch period by an open-loop search from the shaped lattice structure considering all of the dimensions of the pitch space for providing an open-loop search value indicative of the open-loop estimate; and means, responsive to the open-loop search value, for refining the open-loop estimate in each of the dimensions in the pitch space separately by a closed-loop search from the shaped lattice structure for obtaining a closed-loop search value indicative of the pitch value in the respective signal segment.

Claim 21

A system for coding a sound signal in a plurality of signal frames each having a pitch period indicative of the sound signal in the respective signal frame, wherein each signal frame comprises a plurality of signal segments each representing a dimension in a pitch space, and the sound signal in each of the signal segments is characterized by a pitch value, and wherein the pitch values are representable by a point distribution pattern characteristic of the sound signal in a lattice structure for defining codebook indices in the pitch space, and the lattice structure is shaped based on the point distribution pattern for defining a shaped lattice structure, said system comprising: an encoder having: means, responsive to the sound signal, for obtaining an open-loop estimate of the pitch period by an open-loop search from the shaped lattice structure considering all of the dimensions of the pitch space for providing an open-loop search value indicative of the open-loop estimate; and means, responsive to the open-loop search value, for refining the open-loop estimate in each of the dimensions in the pitch space separately by a closed-loop search from the shaped lattice structure for obtaining a closed-loop search value indicative of the pitch value in the respective signal segment for providing information indicative of the shaped lattice structure and the codebook indices; and a decoder having means, responsive to the information, for synthesizing a further sound signal from the codebook indices based on the shaped lattice structure.

Claim 22

A system for coding a sound signal in a plurality of signal frames each having a pitch period indicative of the sound signal in the respective signal frame, wherein each signal frame comprises a plurality of signal segments each representing a dimension in a pitch space, and the sound signal in each of the signal segments is characterized by a pitch value, and wherein the pitch values are representable by a point distribution pattern characteristic of the sound signal in a lattice structure for defining codebook indices in the pitch space, and the lattice structure is shaped based on the point distribution pattern for defining a shaped lattice structure, said system comprising: an encoder having: means, responsive to the sound signal, for obtaining an open-loop estimate of the pitch period by an open-loop search from the shaped lattice structure considering all of the dimensions of the pitch space for providing an open-loop search value indicative of the open-loop estimate; and means, responsive to the open-loop search value, for refining the open-loop estimate in each of the dimensions in the pitch space separately by a closed-loop search from the shaped lattice structure for obtaining a closed-loop search value indicative of the pitch value in the respective signal segment for providing information indicative of the shaped lattice structure and the codebook indices; and a decoder having means, responsive to the information, for synthesizing a further sound signal from the codebook indices based on the shaped lattice structure.