Powerwave Technologies, Inc.

Mark Gurvich

Nikolai Maslennikov

Alex Rabinovich

Jianqing He

Alexander Rabinovich

Bill Vassilakis

Ezmarai Arbab

Ahmad Khanifar

Jianquing He

Matthew J Hunton

An envelope tracking radio frequency (RF) power amplifier having an adaptive envelope signal processing circuit is disclosed. An RF input voltage is sampled by the adaptive envelope signal processing circuit which provides control signals to the power supply which supplies voltages to RF power devices in order to simultaneously satisfy two operating conditions: a) provide best possible efficiency of the power amplifier stages depending on the input signal characteristics and b) provide compensation for RF transistor AM-AM and AM-PM distortion compensation across the power range. In particular, the voltage control provides for constant power amplifier gain across the input signal dynamic range, thus minimizing power amplifier amplitude distortions and extending the useful power amplifier linear dynamic range up to saturation point. The power amplifier thus exhibits better linearity and efficiency than offered by conventional techniques and topologies.

Constant gain nonlinear envelope tracking high efficiency linear amplifier

A high efficiency radio frequency (RF) power amplifier having dynamically controlled back off is disclosed. The RF input voltage is sampled by an adaptive analog signal processing circuit. The adaptive analog signal processing circuit controls the supply voltage to RF amplifier devices, such as LDMOS devices, which varies the efficiency or back off of the power amplifier. The variable supply voltage in turn varies peak power of the amplifier.

High efficiency linear amplifier employing dynamically controlled back off

A delay mismatched feed forward power amplifier is disclosed. Loopincludes a main amplifier and is used to derive a carrier cancelled sample of the main amplifier output. Loopincludes an error amplifier used to amplify the carrier cancelled signal derived from Loopoperation in order to cancel distortion products generated due to the nonlinear nature of the main amplifier. Loopalso utilizes a very short Loopdelay line. A significant efficiency gain is provided due to reduced output power losses associated with the Loopdelay line. Lower output losses also results in lower distortion levels produced by the main amplifier. This, in turn, reduces the size and performance requirements placed on the error amplifier. A smaller and more efficient error amplifier is employed resulting in further amplifier system efficiency improvement. The delay mismatch is compensated by a third control loop, a special adaptive control algorithm or a combination thereof.

Enhanced efficiency feed forward power amplifier with delay mismatched error cancellation loop

A dual loop feedforward power amplifier. A dual loop feedforward power amplifier, comprising an input that provides a multicarrier signal; a first feedforward power amplifier; and a second feedforward power amplifier, wherein the first feedforward power amplifier serves as a main amplifier gain block in the second feedforward power amplifier, wherein the first feedforward power amplifier comprises a carrier cancellation loop and a first error amplifier loop, and wherein the second feedforward power amplifier comprises a third loop and a fourth loop that cancel small signal distortions that are not reduced by the first feedforward amplifier.

System and method of carrier reinjection in a feedforward amplifier

A method for aligning a feed forward radio frequency power amplifier includes applying a radio frequency signal to the feed forward radio frequency power amplifier and monitoring a radio frequency signal from the feed forward radio frequency power amplifier, without opening a break point of the feed forward radio frequency amplifier.

Method for aligning feed forward loops

A group delay adjusting circuit. The group delay adjusting circuit comprises an electronically adjustable variable capacitance, and an electronically variable virtual inductor coupled in parallel to the electronically variable capacitance at a node.

System and method for adjusting group delay

A feed forward power amplifier is disclosed which utilizes three signal cancellation loops. Loopincludes a main amplifier and is used to derive a carrier cancelled sample of the main amplifier output. Loopincludes an error amplifier used to amplify the carrier cancelled signal derived from Loopoperation in order to cancel distortion products generated due to the nonlinear nature of the main amplifier. Loopalso utilizes a very short Loopdelay line. A significant efficiency gain is provided due to reduced output power losses associated with the Loopdelay line. Lower output losses also results in lower distortion levels produced by the main amplifier. This, in turn, reduces the size and performance requirements placed on the error amplifier. A smaller and more efficient error amplifier is employed resulting in further amplifier system efficiency improvement. A spurious signal detector for out-of-band distortion detection and an associated microcontroller for Loopand Loopcontrol are also provided. A third signal cancellation loop is utilized to sample the amplifier output and reduce the carrier level of the signals sampled at the output of the amplifier before providing the sampled output to the spurious signal detector. By significantly reducing the carrier power level relative to distortion power levels a cost effective spurious signal detector can be utilized. This also provides a faster conversion time in Loopcancellation and enhanced cancellation of out-of-band distortion products due to a greater useful dynamic range available for the DSP employed in the spurious signal detector.

Enhanced efficiency feed forward power amplifier utilizing reduced cancellation bandwidth and small error amplifier

A feedforward amplifier. The present invention therefore provides a feedforward amplifier, comprising: a pilot reference generator that generates a pilot signal; a first carrier cancellation loop; a first error amplifier loop including a first error amplifier, wherein the pilot signal is utilized to provide gain stabilization in the first error amplifier a third loop; a second carrier cancellation loop that includes a first phase and amplitude adjuster in module and a second amplitude and phase adjuster disposed between module and module, wherein the pilot signal is utilized to control the adjustment of the second carrier cancellation loop.

Dual loop feedforward power amplifier

A microstrip coupler is provided which includes an controlled capacitance bridge for improved directivity as compared to prior art controlled capacitance bridges. The novel controlled capacitance bridge provides the functionality of prior art wire or ribbon controlled capacitance bridges and also provides the necessary capacitance to compensate for the different phase velocities of odd and even modes in the transmission lines. Both the dimensions of the controlled capacitance bridge and the dimensions of an input microstrip conductor may be adjusted to provide the appropriate level of capacitance. In some embodiments, the controlled capacitance bridge connects segments of an input microstrip conductor. In other embodiments, the controlled capacitance bridge connects microstrip conductors which are configured to couple an input signal from an input microstrip conductor.

Microstrip coupler

A system and method of pilot tone reuse. The present invention therefore provides a feedforward amplifier, comprising: an input that accepts a radio frequency signal having multiple carriers; a first control loop including a main amplifier block and a detector, wherein the first control loop generates a first carrier cancelled signal; a second control loop including a pilot generator, I/Q demodulator, vector modulator and first error amplifier block, wherein the pilot generator, I/Q demodulator and first error amplifier block amplify the first carrier cancelled signal and generates a pilot signal; a third control loop comprising a vector modulator and a second carrier cancellation detector; and a fourth control loop comprising of vector modulator, a second error amplifier block, and a pilot signal receiver for receiving the pilot signal generated by the pilot generator in the second error amplifier block such that the pilot signal is reused by the fourth control loop to thereby further cancel intermodulation distortion in the output of the main amplifier block.

System and method of pilot tone reuse in a feedforward amplifier

A dynamic bias switching circuit is provided that includes a switching unit for switching between a first signal level and a second signal level based on a signal envelope of an input signal to an amplifier.

Systems and methods of dynamic bias switching for radio frequency power amplifiers

A feed forward amplifier employing high efficiency main and/or error amplifiers with amplifier devices biased in a lower bias class. Small signal nonlinearities in the gain response of the amplifier devices are compensated by a small signal gain adjustment circuit. The resulting gain response is substantially linear over the entire usable range of RF input power.

Enhanced efficiency LDMOS based feed forward amplifier

A feed forward RF power amplifier which provides both high efficiency and minimal distortion in broad bandwidth RF applications. The feed forward power amplifier includes a main amplifier biased to provide high efficiency and an error amplifier biased to provide highly linear operation through substantially the entire operating range. Signal peaks which introduce distortion components at the main amplifier output are cancelled by the linear operation of the error amplifier.

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Costa Mesa, CA, United States of America

Mark Gurvich