Ericsson Gmbh

Jim A Rasmusson

David R Irvin

John Joseph Hayes, Jr

Torbjorn Wilson Solve

Robert Allen Zak

Ted G Ericsson

A wireless telephone communication device is operated in a hands-free mode with detected received audio being relayed for output on the speakers of a radio. A single two-frequency FM transmitter or a multi-frequency transmitter that transmits simultaneously on a plurality of channels relays the audio to the FM radio.

Audio-output for a portable radio telephone utilizing a vehicle's AM/FM

A method and apparatus for reducing the echo in a hands-free digital cellular communications system is presented. Acting upon speech signals being present in the downlink, uplink speech frames generated by the hands-free communication device are attenuated to prevent the downlink speech signals from being transmitted at full volume back on the uplink as an echo. Added to the attenutated uplink speech frame is a noise frame generated by the hands-free communication device, which provides a consistent level of background noise to the person at the other end of the call. The noise codeword is further randomly ordered to prevent any modulative effects from the process.

Method and apparatus for echo reduction in a hands-free cellular radio

Selectively compressing the signal supplied to a loudspeaker based upon the volume setting for the sound level to be produced by the loudspeaker improves the intelligibility of human speech produced by a loudspeaker at high volume levels. Compression of the signal to the loudspeaker prevents the loudspeaker from overloading. The level of compression may be adjusted based upon the volume setting. The amplitude of an audio signal sent to a loudspeaker may be increased if below a preselected pivot point and increased if above the pivot point. The amount of increase or decrease in the amplitude may be proportional to the difference between the amplitude of the audio signal and the pivot point. This difference may also be raised to the power of a shape factor to determine the amount of increase or decrease in the amplitude of the audio signal.

Growing community of inventors

Raleigh, NC, United States of America

Jim A Rasmusson