Telefonaktiebolaget Lm Ericsson (publ)

Hans Cavander

Fisseha Mekuria

Per A Ljungberg

Lars Lennartsson

A mobile station in a spread spectrum communications system includes a matched filter that can be divided into segments. On initial acquisition, when a frequency deviation between the expected receiving frequency of the mobile station and the transmitting frequency of the base station is expected to be relatively large, the device can operate in a first synchronisation mode, in which the filter is used divided into segments. On searching for alternative cells, when the frequency deviation is expected to be smaller, the device can operate in a second synchronisation mode, in which the filter is used undivided. Thus, in the first mode, a reduced filter length avoids the difficulties caused by frequency deviation, while, in the second mode, an increased filter length allows faster acquisition.

Detection of correlation between detected transmissions from multiple base stations and a known code in a mobile telecommunications system

A communication device is provided having a speech encoder and a speech decoder and being able to retrieve and store voice messages in a memory. The messages are stored in the memory according to a message format. This format is more compressed than the speech encoding format which is provided by the speech encoder. The device includes a frame interpolation block for decompressing a stored message and thereby creating a signal according to the speech encoding format. A frame decimation block is also provided for compressing a speech encoded signal thereby allowing a corresponding voice message to be stored in the memory according to the message format.

Communication device and method of operation

Apparatuses for noise reduction and noise processing methods for reducing noise in audio signals are presented. The noise level of an input signal at an input terminal is measured and the noise-to-signal ratio is established. A reduced voice activity detector is used to determine whether the input signal comprises speech or not. If the measured noise level exceeds a threshold level a switch connects the input signal to means for noise reduction. However, if the measured noise level does not exceed the threshold level, i.e. when noise reduction is not needed, the switch disconnects the means for noise reduction and the input signal is passed unchanged. Power is saved by powering off the means for noise reduction when it is not needed.

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Aspvagen, Sweden

Hans Cavander