Sony Ericsson Mobile Communications Ab

Sony Corporation

Sony Mobile Communications Ab

Joakim Eriksson

Jonny Strandh

Filip Skarp

Filip Jorgensen

The invention is directed to echo cancellation for a microphone system. An exemplary microphone system comprises a first transistor, wherein a gate terminal of the first transistor is connected to a ground terminal via a microphone electret element, the microphone electret element being associated with a capacitance and a voltage, the microphone electret element reverse biasing the first transistor; and a second transistor in parallel with the first transistor, wherein a gate terminal of the second transistor is connected to the ground terminal via a capacitor, the capacitance of the capacitor being selected to suppress at least a portion of a common mode signal, and wherein the gate terminal of the second transistor is not connected to the microphone electret element. The common mode signal comprises the echo, which may be the output of a speaker system that is received as input to the microphone system.

Echo cancellation

A system includes a first matching network having a first impedance and a second matching network having a second impedance, where the second impedance is different than the first impedance. The system further includes a switching connector having first and second switching positions, where when the switching connector is in the first switching position an input terminal is connected through the first matching network to a first antenna and where when the switching connector is in the second switching position the input terminal is connected through the second matching network to a second antenna and the first antenna is connected to ground.

Two-way antenna connector

The present invention relates to a portable communication device and a method of controlling the matching of an antenna in a portable communication device. The device may include an antenna; a radio circuit to send a radio frequency signal to the antenna via a signal path; a matching network including a number of network components and configured to be in the signal path; a detector configured to detect an electromagnetic field from the antenna; and a control unit configured to control matching of the antenna by influencing at least one of the first matching network or the antenna based on the detected electromagnetic field.

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Lund, Sweden

Joakim Eriksson