Conexant Systems, Inc.

Nokia Corporation

Skyworks Solutions, Inc.

Robert Edmund Grange

Donald Brian Eidson

Mats Lindstrom

Brian Eidson

Robert Cunningham

A transmitter for modulating an RF carrier signal with an input digital data stream is disclosed. The transmitter has a processor for generating digital phase and digital amplitude signals which characterise the input digital data stream, a signal generator for generating an RF carrier signal with a phase property defined by the generated digital phase signal, an amplifier arranged to receive the RF carrier signal as an input, and a bi-level switching circuit responsive to the generated digital amplitude signal to switch between the two levels to generate a voltage signal for supplying power to the amplifier.

Method and apparatus for modulating a radio signal using digital amplitude and phase control signals

An EMI shield for blocking and dissipating electromagnetic interference. The EMI shield includes a primary conductive member having a plurality of catches extending into a plurality of receptacles defined in an absorptive member so as to firmly connect the members. Advantageously, the absorptive member is sufficiently solid to be retained against the primary conductive member during normal use. In addition, the absorptive member is constructed of materials capable of withstanding a temperature range of 139&#xb0; C. to 260&#xb0; C. associated with most soldering operations. In this manner, the conductive and absorptive members can be attached prior to soldering of the EMI shield to electronic circuitry of a mobile station. The catches may have sharp edges allowing the absorptive member to be pressed onto the catches.

Electromagnetic interference shield and method of making the same

A highly efficient radio frequency (RF) transmitter provides both wide bandwidth and an extended power control range. The RF transmitter includes stage switching, bias adjustment, and drain supply modulation. These components are used to provide fine and coarse power control and EER envelope fluctuations. The RF transmitter is useful in wireless communications to increase both handset talk time and battery life.

RF transmitter with extended efficient power control range

An envelope feedforward technique is described that provides efficient, variable-power, linear amplification of an input signal. An input signal having phase and amplitude components is separated (decomposed) into an FM portion and an envelope portion. The FM portion contains the high frequency phase and frequency information from the input signal. The envelope portion contains the low frequency amplitude information from the input signal. An envelope combiner uses the envelope signal to amplitude-modulate the FM signal to produce an output signal. Spectral regrowth of the output signal is reduced by adjusting the relative time delays in the signal path of the envelope signal and the FM signal such that the FM signal and the envelope signal arrive at the envelope combiner at the same time. The envelope feedforward technique may be used to increase battery life in a handheld mobile RF unit such as a cellular telephone. An efficient Class D switching amplifier is constructed using a dual-gate FET by applying the envelope signal to the first gate to vary the transconductance of the FET and by applying the FM signal to the second gate to switch the FET on and off.

Envelope feedforward technique with power control for efficient linear RF power amplification

A power amplifier for use in a wireless communication system operates like a quadrature mixer with conversion gain. The amplifier includes a local oscillator that generates two reference signals 90&deg; out of phase with respect to each other. Four quadrature mixer elements receive signals representing the in-phase and quadrature components of a baseband signal. Each quadrature mixer amplifies the in-phase or the quadrature component of the baseband signal while upconverting with the corresponding reference signal.

Power amplification using a direct-upconverting quadrature mixer topology

A power amplifier that amplifies an electrical signal that is passed through a power amplification array. The power amplifier is employed in various applications including cellular telephones, radio frequency signal transmission, and other electrical signal applications requiring power amplification. The power amplifier contains a number of power amplifiers arranged in a power amplifier array. To reproduce a particular envelope profile, a selected number of the power amplifiers of the power amplifier array is switched ON, whereas another selected number of the power amplifiers of the power amplifier array are switched OFF. All elements are fed with an RF signal containing phase information as well. The amplified, output signal provided after the power amplifier array is fed to an antenna for signal transmission. Impedance matching circuitry is employed between the power amplifier array and the antenna to provide efficiency for those applications having low power budgets or seeking to operate with extremely high efficiency. The present invention provides a solution that is extremely energy efficient, making it ideally suited for applications having low available power budgets such as battery operated devices such as cellular telephones. From one perspective, the power amplifier array is operated as if it were a digital device. For example, each of the individual power amplifiers of the power amplifier array is either switched ON or switched OFF, as described above, and a selected number of the power amplifiers provides the desired level for the specific application.

Power amplifier operated as an envelope digital to analog converter with digital pre-distortion

The envelope of a non-constant envelope signal is limited to certain maximum and minimum values. An envelope value is calculated for each pair of I-Q samples of the non-constant envelope signal and then is compared to the maximum and minimum values. If the envelope value lies above or below the maximum and minimum values, the I and Q signals are scaled so that the envelope value lies between these values. In some embodiments, the threshold values are selected to ensure that the probability that the envelope value will exceed these values is less than a predetermined amount (e.g., between 0.01 and 0.001).

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San Diego, CA, United States of America

Robert Edmund Grange