Cambridge Silicon Radio Limited

Sameer Gadre

Xuejing Sun

Rogerio Guedes Alves

Kuan-Chieh Yen

Michael Christopher Vartanian

Scott Plude

A method and apparatus for selectively replacing damaged portions of a data stream. The method comprises analyzing the data stream to identify damaged portions therein; selecting a damaged portion for replacement; and replacing the selected damaged portion. The selected damaged portion is selected for replacement in dependence on a rate of replacement, the rate of replacement being that at which previous portions of the data stream have been replaced.

Error concealment

The perceived quality of a narrowband speech signal truncated from a wideband speech signal is improved by generating in a third frequency band third speech components matching first speech components in a first frequency band of the narrowband signal, and generating in a fourth frequency band fourth speech components matching second speech components in a second frequency band of the narrowband signal. A first gain factor is applied to the third speech components to generate adjusted third speech components, and a second gain factor is applied to the fourth speech components to generate adjusted fourth speech components, the gain factors being selected such that the ratios of the average powers of the adjusted third and fourth speech components to the average power of the first speech components are predetermined values.

Speech intelligibility

The perceived quality of a speech signal is improved by estimating the average power of first and second signal components and applying a first gain factor to the second signal components to generate adjusted second signal components. The first gain factor is selected such that on application of the first gain factor to the second signal components, the ratio of the average power of the first signal components to the average power of the adjusted second signal components would be a first predetermined value, the first predetermined value being such as to inhibit perceptual distortion of the improved speech signal.

Method and apparatus for improving intelligibility of audible speech represented by a speech signal

A method and apparatus for estimating the pitch period of a signal. The method includes identifying a first candidate pitch period by performing a search only over a first range of potential pitch periods. The method further includes determining a second candidate pitch period by dividing the first candidate pitch period by an integer, wherein the second candidate pitch period is outside the first range of potential pitch periods. The method further includes selecting as the estimate of the pitch period of the signal the smaller of the candidate pitch periods that is such that portions of the signal separated by that candidate pitch period are well correlated.

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Northville, MI, United States of America

Sameer Gadre