Abstract: 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.

Abstract: 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.

Abstract: 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.

Abstract: 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° 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.

Abstract: 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° 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.

Abstract: 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.

Abstract: 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).