Abstract: 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 (10) includes a microphone (11) to generate an audio signal, an analog automatic level control (ALC) circuit (13), coupled to an output of the microphone (11), to control a level of the audio signal output from the microphone (11) and output a level-controlled audio signal, and a DSP (digital signal processing) circuit (14) to process the level-controlled audio signal output from the ALC circuit (13). The ALC (13) allows audio signals to be captured by the microphone (11) 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 (14) for enhanced performance.

Abstract: 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 (10) includes a microphone (11) to generate an audio signal, an analog automatic level control (ALC) circuit (13), coupled to an output of the microphone (11), to control a level of the audio signal output from the microphone (11) and output a level-controlled audio signal, and a DSP (digital signal processing) circuit (14) to process the level-controlled audio signal output from the ALC circuit (13). The ALC (13) allows audio signals to be captured by the microphone (11) 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 (14) for enhanced performance.

Abstract: 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.

Abstract: A circuit for controlling processing of audio data and command data in a digital cordless telephone receiver includes a digital audio data path for processing digital audio information received; and a command data path for controlling the digital audio data path responsive to receiving command data.

Abstract: 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.

Abstract: 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.

Abstract: 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.

Abstract: An apparatus and method for selecting a new channel for communicating with a remote wireless device in which the quality of data transmitted on a communication channel simultaneously with audio information is used to determine whether the new communication channel should be selected.

Abstract: 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.

Abstract: A remote wireless intercom and other devices for communicating with a cordless telephone system are disclosed. The remote wireless intercom includes a transmitter, a receiver, a speaker, a microphone, a battery interface, and a housing which carries these components. A method of communicating between the remote wireless intercom and a cordless telephone device involves the steps of detecting an intercom voice communication request at the remote wireless intercom; wirelessly transmitting the intercom voice communication request from the remote wireless intercom to the a cordless telephone device; and engaging the remote wireless intercom in an intercom voice communication session with the cordless telephone device after transmitting the intercom voice communication request. Preferably, the cordless telephone device is a cordless base station and the intercom voice communication session takes place between the remote wireless intercom and a cordless telephone.

Abstract: A method of simultaneously communicating voice and data on the same channel in an analog cordless telephone system involves generating an analog signal from an audible voice signal during a cordless telephone call; generating a frequency shift keying (FSK) signal from digital data having a nominal frequency of about 20 KHz; summing the analog signal and the FSK signal to produce a composite analog and digital signal; modulating a radio frequency (RF) carrier with the composite analog and digital signal to produce a modulated RF carrier; and transmitting the modulated RF carrier.