Abstract: The invention provides a power sharing amplifier system having an N by N transform matrix circuit, N amplifiers and an N by N inverse transform matrix circuit. The N by N transform matrix circuit has N input ports that respond to M input signals and provide N transform matrix input signals, where M is less than N. The N by N transform matrix circuit features at least one input port that does not receive an input signal but instead is coupled to ground. The N amplifiers respond to the transform matrix input signals and provide N amplified transform matrix input signals. The N by N inverse transform matrix circuit responds to the N amplified transform matrix input signals and provides N inverse transform matrix amplified output signals to output ports. Moreover, the N by N inverse transform matrix circuit features at least one output dissipation port that is coupled to ground to dissipate the intermodulation products contain thereon.

Abstract: An apparatus for communicating, over a single transmission medium, two signals of substantially the same center frequency. The apparatus offsets in frequency one of the signals by combining the signal with the signal from a local oscillator. The apparatus then transmits the two signals, one offset from the other, as well as the signal from the local oscillator to allow for recovery of the two signals with a precise correction for the offset. In particular, the transmission medium is an optical fiber and the two signals are a main RF signal and a diversity RF signal received, respectively, by a main element and a diversity element of a diversity antenna system. The invention is of use, for example, in providing to a microbase station a main RF signal and its diversity RF signal received at a diversity antenna system remote from the microbase station and connected to the microbase station by an optical fiber.

Abstract: The invention provides a power sharing amplifier system for a cellular communications system, having with an 8th order transform matrix circuit, eight power sharing amplifiers and an 8th order inverse transform matrix circuit. The 8th order transform matrix circuit has six input ports and responds to six RF input signals for providing 8th order transform matrix RF input signals. The 8th order transform matrix circuit also has two input ports that do not receive input signals, but instead are coupled through a resistor to ground. The eight power sharing amplifiers respond to the 8th order transform matrix RF input signals, for providing eight amplified transformed RF signals. The 8th order inverse transform matrix circuit responds to the eight amplified transformed RF signals, for providing six inverse transform amplified RF output signals to six output ports.

Abstract: An apparatus for linearizing the output of a wideband amplifier by digitally predistorting the input to the amplifier in a way that just compensates for the distortion in the amplified signal, comprising a pipeline controller (12), for providing pipeline controller signals, and a pipelined predistorter (11), consisting of several stations, serially connected to each other, wherein each station performs one or more tasks concurrently, under the direction of the pipeline controller (12). The result is a digital predistorter with a bandwidth large enough to linearize, by itself, the entire output of a wideband amplifier. More generally, an apparatus for linearizing a wideband amplifier by using digital signal processing performed using a pipeline architecture, as opposed to using a sequential processing architecture, under the supervision of a pipeline controller.

Abstract: In a feed forward amplifier (100), a main amplifier (125) is coupled between an input (102) at which an input signal is received and an output (173) at which an output signal is provided. The output signal is an amplification of the input signal. A sample of the output signal is compared (144) with a sample of the input signal to produce a difference signal indicative of distortions introduced by the main amplifier (125). An error amplifier (165) provides a distortion signal which is an amplification of the difference signal, and the distortion signal is combined (169) with the output signal to compensate for main amplifier distortions. A random frequency, constant amplitude sine wave pilot signal is combined (117) with the input signal, and a correlation power detector (194,195,202,212,213) is provided to determine the magnitude of the pilot signal in the output signal. The gain and phase of the difference signal is then adjusted (155) to minimize the magnitude of the pilot signal in the output signal.