Blackberry Corporation

Glenayre Electronics, Inc.

Mohammad Aamir Husain

Bhaskar Bhattacharya

Mark Robert Every

Michael Andrew Percy

Frank Linseisen

Patricia Fern Kavanagh

A method of echo cancellation in hands-free communication is disclosed. The method includes: receiving, via a receive signal processor, a far-end audio signal; providing the far-end audio signal to: an acoustic echo canceller module as a reference signal, and at least one loudspeaker for playback; determining an external gain value associated with the far-end audio signal, the external gain applied to the far-end audio signal downstream of the receive signal processor and prior to playback from the at least one loudspeaker; adjusting at least one parameter of the acoustic echo canceller module based on the external gain value; receiving playback output of the far-end audio signal from the at least one loudspeaker as an input signal to a microphone; and processing the microphone input signal by the adjusted acoustic echo canceller module to produce an echo-cancelled signal.

System and method for reducing distortion and echo leakage in hands-free communication

A sub-band processing system for reducing computational complexity and memory requirements is disclosed. The sub-band processing system includes: a first logic that partitions and stores a frequency spectrum of bins of real and imaginary data into a smaller number of sub-bands; a second logic that executes a first lossy compression for a first set of the sub-bands, wherein the first set includes those sub-bands having indices that are greater than or equal to a first index; and a third logic that executes, subsequent to a frequency spectrum processing of the lossy compressed data rendered by the second logic, a second lossy compression for a second set of the sub-bands, wherein the second set includes those sub-bands having indices that are less than the first index and greater than or equal to a second index.

Method for multi-stage compression in sub-band processing

A method of encoding signal segments which represent unvoiced plosives. The signal segments to be encoded are contained within a speech signal divided into m&equals;1, . . . , N frames. Each frame is subdivided into l&equals;1, . . . , L subframes. The speech signal has a gain g,(l) within each subframe. An energy measure e,(l) representative of the signal segments' energy content is defined. An energy threshold e,(l) representative of a sudden energy change characteristic of an unvoiced plosive is also defined. For each frame, the energy measure e,(l) and the energy threshold e,(l) are derived for each subframe within that frame. If e,(l)&lE;e,(l) for each subframe within a particular frame, then a plosive locator l,&equals;0 and a plosive index i,&equals;0 are assigned to that frame to indicate absence of a plosive within that frame. If e,(l)>e,(l) for any subframe within the frame, then that frame's plosive locator l,is assigned a non-zero value, with the plosive locator's value indicating location of the plosive at a transition point immediately following that one of the subframes within the frame for which e,(l)&minus;e,(l) is greatest; and, that frame's plosive index i,is assigned a non-zero value representing presence of a plosive within that frame.

Location and coding of unvoiced plosives in linear predictive coding of speech

A method and apparatus for reducing peak-to-average power ratio in a paging transmitter broadcasting an independent sideband amplitude modulation protocol is disclosed. A digital signal, for example a digital voice signal, is provided to a control gain generator which generates a digital gain sequence. The digital gain sequence is such that during peak values in the digital signal the gain is low and during low values in the digital signal the gain is high. The digital gain sequence is multiplied with the digital signal to compress the dynamic range of the digital signal.

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Surrey, Canada

Mohammad Aamir Husain