Abstract: An amplifier includes an RF power amplifier and a predistortion circuit coupled to the power amplifier. The predistortion circuit affects an input path of an RF input signal to the power amplifier. The predistortion circuit is operable for detecting a level of an input signal and generating a delay in the input path based on the input signal level. This enables predistortion correction of a new distortion term AM/DM, in addition to the well known AM/AM and AM/PM terms. The new AM/DM term represents the distortion that is caused by the delay modulation of the input signal as a function of the envelope power variation within the input signal.

Abstract: An uncorrelated adaptive predistorer configured for use with an RF power amplifier having an input loop configured to be coupled to the input of the RF power amplifier an output loop coupled to the output of the RF power amplifier. Such an input loop includes a look-up table containing predistortion values to be apply to an input signal, in response to a monotonically increasing function of the input signal power, for forming a predistorted input signal. Such an output loop configured to measure an intermodulation distortion product of the RF power amplifier output resulting from the predistorted input signal, and operable to update the predistortion values in the look-up table.

Abstract: An amplifier has a main amplifier circuit with multiple amplification stages, including a driving stage and an auxiliary amplifier circuit with multiple amplification stages, including a driving stage. A splitter circuit splits an input signal to provide path asymmetry in splitting the input signal between the main amplifier path and auxiliary amplifier path. The driving stage of the auxiliary amplifier circuit has a power rating higher than the power rating of the driving stage of the main amplifier circuit to provide a gain asymmetry in the amplifier circuit paths.

Abstract: An amplifier includes a main amplifier circuit with an input and output. At least one auxiliary amplifier circuit has an input and output, and is selectively operable to operate in combination with the main amplifier circuit. A signal combining network is coupled with outputs of the main amplifier circuit and auxiliary amplifier circuit and is operable to combine amplifier circuit output signals at an output port. The main and auxiliary amplifier circuits operate in an operational frequency band, and a delay element is coupled to the input of the auxiliary amplifier to introduce a delay to that input that is configured for introducing a delay that is an integer multiple of a wavelength at a frequency within the operational frequency band.

Abstract: A control circuit for a feed forward amplifier provides for pausing control and continuous adjustment of a control signal, provides for the control signal to start at any point, provides for rapid convergence, and that does not perturb the system up or down one step to confirm the convergence of the system. The control circuit receives a sampled version of a feed forward amplifier output signal, generates a non-offset control signal based on the sampled output signal, separately generates an offset voltage by reference to voltages stored in a table or based on the non-offset control signal, and combines the non-offset control signal with the offset voltage to produce a control signal. The feed forward amplifier may then adjust an error signal based on the control signal to produce an adjusted error signal that is capable of reducing distortion in the feed forward amplifier.

Abstract: A control circuit for a feed forward amplifier provides for pausing control and continuous adjustment of a control signal, provides for the control signal to start at any point, provides for rapid convergence, and that does not perturb the system up or down one step to confirm the convergence of the system. The control circuit receives a sampled version of a feed forward amplifier output signal, generates a non-offset control signal based on the sampled output signal, separately generates an offset voltage by reference to voltages stored in a table or based on the non-offset control signal, and combines the non-offset control signal with the offset voltage to produce a control signal. The feed forward amplifier may then adjust an error signal based on the control signal to produce an adjusted error signal that is capable of reducing distortion in the feed forward amplifier.

Abstract: An uncorrelated adaptive predistorer configured for use with an RF power amplifier having an input loop configured to be coupled to the input of the RF power amplifier an output loop coupled to the output of the RF power amplifier. Such an input loop includes a look-up table containing predistortion values to be apply to an input signal, in response to a monotonically increasing function of the input signal power, for forming a predistorted input signal. Such an output loop configured to measure an intermodulation distortion product of the RF power amplifier output resulting from the predistorted input signal, and operable to update the predistortion values in the look-up table.

Abstract: A modulated elongate cavity oscillator with minimized modulation nonlinearities includes a first cavity having dimensions which determine the fundamental resonant frequency of the oscillator, a gain element disposed in said first cavity that provides amplification to sustain oscillation, and a varactor diode disposed in said first cavity for modulating the fundamental frequency. A first waveguide is coupled to the first cavity for absorbing modes higher than the mode of the fundamental frequency which have an electric field maxima concurrent with the longitudinal center line of the first cavity. A second waveguide is coupled to the first cavity for absorbing modes higher than the mode of fundamental frequency which have an electric field minima concurrent with the longitudinal center line of the first cavity, whereby the first and second waveguides provide effective attenuation of higher order modes such that modulation nonlinearities due to the existence of higher order modes are substantially eliminated.