Abstract: A control system for a linear feed-forward amplifier, using the ratio of measured spurious energy. Measuring receivers are coupled to two monitoring points to measure the spurious energy content in the error signal and at the main output of a feed-forward amplifier. The control system measures the ratio of these detected spurious, and uses this to optimize the settings of the second loop distortion cancellation. With the addition of an extra monitoring point, the same technique may also be used to control an adaptive predistorter prior to the main amplifier.

Abstract: A digital signal processing based feed forward amplifier includes a delay circuit which receives a portion of the input signal and generates a delayed input signal. A first analog to digital converter receives another portion of the input signal and generates a digitized input signal. A main amplifier receives the delayed input signal and generates a main amplified signal. A second analog to digital converter receives at least a portion of the main amplified signal and converts it to a digitized main amplified signal. A digital signal processor receives the digitized input signal and the digitized main amplified signal and generates a digitized error signal. The digitized error signal is converted to an analog error signal by a digital to analog converter. An error amplifier receives the analog error signal and amplifies it to generate an amplified error signal.

Abstract: A control system for a linear feed-forward amplifier, using the ratio of measured spurious energy. Measuring receivers are coupled to two monitoring points to measure the spurious energy content in the error signal and at the main output of a feed-forward amplifier. The control system measures the ratio of these detected spurious, and uses this to optimize the settings of the second loop distortion cancellation. With the addition of an extra monitoring point, the same technique may also be used to control an adaptive predistorter prior to the main amplifier.

Abstract: The invention relates to a low cost feed forward RF power amplifier arrangement for amplifying an RF input signal using a main power amplifier operating as a class A/B amplifier. The method and apparatus modify the input signal to the main amplifier to compensate for the distortion added by the main power amplifier. The circuit provides for injecting a delayed version of the input signal, through a fixed gain-phase circuity, at a point whereby the resulting signal is amplified by the error amplifier of the second loop. A digitally controlled processor iteratively modifies various phase and gain controls to adjust the output of the amplifier. Different gain and phase control lines are iteratively updated at different rates.

Abstract: An apparatus for either combining a plurality of high frequency RF signal inputs or splitting a single RF frequency input into a plurality of RF signal outputs employs a switchable combining/splitting section and a switchable matching section. The switchable combining/splitting section operates to either combine the RF signal inputs to a common summed output or to take a matched input and to split it into a plurality of outputs. The matching section operates to switchably match the impedance presented by the combining/splitting section to achieve a minimum or zero insertion loss through the apparatus.

Abstract: Systems and methods are taught whereby amplification of narrowband signals may be accomplished by linear power amplifiers requiring the presence of a communicated broadband signal in order to make internal adjustments necessary for linear operation. A preferred embodiment is described utilizing an input of a distributed amplifier assembly unused by the signals of interest in order to inject an emulated CDMA tone operable as a pilot tone for use by the linear power amplifiers.

Abstract: A method and apparatus reduce the out-of-band frequency components of an RF amplified signal, preferably a CDMA signal, which has a carrier frequency which is not known in advance. The apparatus and method feature locating the frequency of the incoming signal by examining an RF output signal having both in-band frequency components and out-of-band frequency components. Typically the output signal is generated using a high-power, Class A/B amplifier. Once the frequency of the carrier has been determined, the out-of-band components are used to generate control signals which, in, for example, a feedback or feedforward circuitry, reduce the energy of the out-of-band signals and thereby provide a more linear amplifier transfer function.

Abstract: A method and apparatus for reducing out-of-band frequency components of an RF amplified input signal, the amplified signal having both in-band frequency components and out-of-band frequency components, employ a feedforward network in which a microprocessor can sweep a frequency generator output connected to a mixer, the other input of the mixer being the amplified output, to find the carrier frequency of the input signal, and thereafter modify or control the feedforward circuit to reduce out-of-band frequency component energies in a particular manner. For example, gain and phase of a variable gain-phase network in a feedforward circuit structure can be modified for reducing the out-of-band frequency component energy.

Abstract: A method and apparatus for reducing out-of-band frequency components of an RF signal having a carrier frequency which is not known in advance employ a control signal to vary adjustable bias parameters of the circuit. In particular embodiments, the RF signal is generated from a MOSFET power amplifier, which introduces distortion components into its output signal. Bias parameters of the MOSFET amplifier can be varied to reduce out-of-band frequency components, that is, out-of-band distortion. In addition, other elements of the network can be controlled by varying bias parameters, for example, a predistorter.