Thomson Licensing

Thomson Licensing S.a.

Wilhelm Ernst Riedl

Chandra Mohan

Hung Chi Lai

Joel David Sawaski

Frank Alan Nardelli

Zhiming Zhang

Kent Joseph Nysewander

Kenneth Mills

Audio processing systems, such as full duplex digital telephone systems, are provided in which analog automatic level control (ALC) circuitry is employed to automatically control and stabilize the microphone output audio signal levels to a constant level for optimal digital signal processing. For example, an audio communication device () includes a microphone () to generate an audio signal, an analog automatic level control (ALC) circuit (), coupled to an output of the microphone (), to control a level of the audio signal output from the microphone () and output a level-controlled audio signal, and a DSP (digital signal processing) circuit () to process the level-controlled audio signal output from the ALC circuit (). The ALC () allows audio signals to be captured by the microphone () with wide dynamic range, while stabilizing the microphone output level within a reduced dynamic range compatible with the limited dynamic range of the DSP circuitry () for enhanced performance.

Full duplex telephone system employing automatic level control for improved digital signal processing of audio signals

An analog cordless telephone has a handset and a base. The handset and/or the base of the telephone may include the following components. A phase locked loop (PLL) and a voltage controlled oscillator (VCO), adapted to be shared between a receive path and a transmit path. A first analog gate is adapted to gate a received audio signal on and off, in response to a clock signal. A second analog gate is adapted to gate a transmit audio signal on and off, in response to an inverted version of the clock signal. The transmit audio signal is enabled when the received audio signal is gated off, and the VCO is further adapted to be modulated by the enabled transmit audio signal to output a modulated RF signal.

Architecture for cordless telephones

A variable aperture coding/decoding system suitable for use in a spread spectrum system provides multiple phase coding of an input NRZ bitstream. Each bit of a coded output signal is coded to encompass a predetermined different number of clock periods depending on the logic level of the input signal. A coded bit exhibits a predetermined reference number of clock periods, eg., 9, when the input signal does not exhibit a logic level transition. When the input signal exhibits a phase change from a 0 to a 1 logic level, the bit width of an associated coded bit is increased by 1 clock period, to 10 clock periods. When the input signal exhibits a phase change from a 1 to a 0 logic level, the bit width of an associated coded bit is decreased by 1 clock period, to 8 clocks periods. Thus the coded output signal may contain three types of information represented by a bit width change proportional to predetermined factor N.

Digital signal modulation system

The transmission power of a wireless device is adapted in response to a determination that errors within a data message are above a threshold level. The data message is simultaneously transmitted with available audio information via a channel supporting audio and non-audio data in respective first and second spectral regions.

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Indianapolis, IN, United States of America

Wilhelm Ernst Riedl