Abstract:
A power amplifier includes an amplifier element and overstress management circuitry coupled to the amplifier element. The overstress management circuitry is configured to detect an overstress condition of the amplifier element and adjust one or more operating parameters of the amplifier element in response to the detection of an overstress condition of the amplifier element. Using the overstress management circuitry prevents damage to the amplifier element that may occur due to uncorrected overstress conditions which may degrade or destroy a gate oxide of the amplifier element. Accordingly, the longevity of the amplifier element is improved.
Abstract:
Radio frequency power amplifier circuitry includes an amplifier element, power supply modulation circuitry, and bias modulation circuitry. The amplifier element is configured to amplify an RF input signal using a modulated power supply signal and a modulated bias signal to produce an RF output signal. The power supply modulation circuitry is coupled to the amplifier element and configured to provide the modulated power supply signal. The bias modulation circuitry is coupled to the amplifier element and the power supply modulation circuitry and configured to receive the modulated power supply signal and provide the modulated bias signal. Notably, the modulated bias signal is a function of the modulated power supply signal such that the modulated bias signal is configured to maintain a small signal gain of the amplifier element and the phase of the RF input signal at a constant value as the modulated power supply signal changes.
Abstract:
A linearization circuit that reduces intermodulation distortion in an amplifier output receives a first signal that includes a first frequency and a second frequency and generates a difference signal having a frequency approximately equal to the difference of the first frequency and the second frequency. The linearization circuit generates an envelope signal based at least in part on a power level of the first signal and adjusts a magnitude of the difference signal based on the envelope signal. When the amplifier receives the first signal at an input terminal and the adjusted signal at a second terminal, intermodulation between the adjusted signal and the first signal cancels at least a portion of the intermodulation products that result from the intermodulation of the first frequency and the second frequency.
Abstract:
A linearization circuit reduces intermodulation distortion in a differential amplifier that includes a first stage and a second stage. The linearization circuit receives a first signal that includes a first frequency and a second frequency and generates a difference signal having a frequency approximately equal to the difference of the first frequency and the second frequency, generates an envelope signal based at least in part on a power level of the first signal, and adjusts a magnitude of the difference signal based on the envelope signal. When the differential amplifier receives the first signal at an input terminal, the first stage receives the adjusted signal, and the second stage does not receive the adjusted signal, intermodulation between the adjusted signal and the first signal cancels at least a portion of the intermodulation between the first frequency and the second frequency from the output of the differential amplifier.
Abstract:
An apparatus for controlling the generation of a radio frequency transmit signal includes a control module configured to control at least one power amplifier stimulus of a power amplifier module based on information related to at least one intermodulation product caused during generation of an amplified radio frequency transmit signal amplified by the power amplifier module. The amplified radio frequency transmit signal has at least two spectral clusters allocated for data transmission.
Abstract:
A power amplifier includes an amplifier element and overstress management circuitry coupled to the amplifier element. The overstress management circuitry is configured to detect an overstress condition of the amplifier element and adjust one or more operating parameters of the amplifier element in response to the detection of an overstress condition of the amplifier element. Using the overstress management circuitry prevents damage to the amplifier element that may occur due to uncorrected overstress conditions which may degrade or destroy a gate oxide of the amplifier element. Accordingly, the longevity of the amplifier element is improved.
Abstract:
A receive frequency band interference protection system includes an input terminal for receiving an input signal and a dividing coupler coupled to the input terminal. The dividing coupler is configured to divide the input signal into a first signal and a second signal. The system further includes a first signal path and a second signal path. The first signal path includes a delay, and it is coupled to the dividing coupler and configured to receive the first signal. The second signal path is coupled to the dividing coupler and configured to receive the second signal. The second signal path includes an attenuator coupled to the dividing coupler and a predistortion linearizer coupled to the attenuator. The system further includes a combining coupler and an output terminal. The combining coupler is coupled to the first signal path and the second signal path. The combining coupler is configured to obtain a sum of the respective outputs of the first signal path and the second signal path. The output terminal is coupled to the combining coupler and configured to send out the sum.
Abstract:
A method for clipping a wideband signal in order to eliminate signal overshots having an amplitude above a predefined threshold before submitting the wideband signal to a power amplifier. The method subtracts, from the wideband signal, filtered pulses in phase with the wideband signal, each filtered pulse corresponding to an overshot, and the amplitude of each filtered pulse being dependant on the amplitude of the corresponding overshot and on the predefined threshold. The subtraction step is repeated at least twice on the wideband signal.
Abstract:
A transmitter clips a transmission signal before transmission in order to reduce the strength of at least one peak of the transmission signal exceeding a predetermined threshold. The transmitter includes a clipper having a minimizer, a filter and an adder. The minimizer minimizes of a cost function with respect to an optimization signal, the cost function having weighted terms as a function of the optimization signal. The terms relate to an effective modulation distortion and an effective overshoot exceeding the predetermined threshold. The filter forms a clipping signal by filtering the optimization signal formed as a result of the minimization according to the spectrum emission mask requirements of the radio system. The adder subtracts the clipping signal from the transmission signal.