359 results about "Doherty amplifier" patented technology

A predistortion circuit for a microwave amplifier and more particularly to predistortion circuit configured as a Doherty amplifier. The predistortion circuit is adapted to be coupled to a downstream Doherty amplifier to precompensate for the gain compression and phase expansion of the downstream Doherty amplifier as the input power level is increased while simultaneously reducing the intermodulation (IM) distortion. In order to provide precompensation, the precompensation circuit is operated at bias level to provide gain expansion and phase compression to cancel out the gain compression and phase expansion of the downstream Doherty amplifier to provide a higher overall linear power added efficiency (PAE).

A transmission signal and a pilot signal are predistorted by a digital predistorter 13 by use of a power-series model, and the predistorted output is converted by a digital-analog converter 14 to an analog signal. The analog signal is up converted by a frequency converter 15 to an RF-band signal, which is transmitted after being power-amplified by a Doherty amplifier 16. The pilot signal is extracted by a pilot signal extractor 17 from the output from the Doherty amplifier, and the extracted pilot signal is down converted by a frequency converter 18 to a baseband signal. The baseband pilot signal is converted by an analog-digital converter 19 to a digital pilot signal. A control part 21 detects an odd-order distortion component from the digital pilot signal, and based on the detected result, controls parameters of the digital predistorter.

A first control unit controls a bias applied to the peak amplifier to (a) make a peak amplifier operate as class C when the level of the input signal is lower than a first threshold value, to (b) make the peak amplifier operate as class AB with a second conduction angle substantially equal to a first conduction angle, when the level of the input signal is higher than a second threshold value higher than the first threshold value, and to (c) make the peak amplifier operate as class AB with a third conduction angle smaller than the first conduction angle, when the level of the input signal is not less than the first threshold value and not more than the second threshold value.

The present invention is intended to provide a Doherty amplifier that can accomplish a linear amplifying and a power combining operation closer to the ideal in a simple configuration. The configuration comprises gain compensator 6 that is composed of a parallel circuit made of an anti-parallel diode and a resistor that is disposed at a position ahead of peak amplifier 4 included in the Doherty amplifier. Setting the gain in gain compensator 6 allows peak amplifier 4 to be compensated for the operation characteristic, when peak amplifier 4 is operating, based on the gm characteristic of peak amplifier 4.

An efficient linear amplifier according to the present invention comprises a primary amplifier for providing power to a load and an auxiliary amplifier for generating an artificial reflection signal. The artificial reflection signal may have a predetermined phase difference as compared to the output signal supplied to the load. The amplifying circuit also includes a coupler connecting the primary amplifier to the load. The coupler includes a load port connected to the load, a primary port connected to an output of the primary amplifier, and an auxiliary port connected to an output of the auxiliary amplifier such that the artificial reflection signal changes an apparent impedance of the load as seen by the primary amplifier.

In a power amplifier a Doherty amplifier is provided with an output higher harmonic reflection circuit that is connected to the output terminal of a first FET chip and sets an even-numbered higher harmonic load of an output signal at the output terminal to be a short-circuit, or at a low impedance approximating a short-circuit, and sets an odd-numbered higher harmonic load of an output signal at the output terminal to be an open-circuit, or a high impedance approximating an open-circuit.

An enhanced Doherty-configured amplifier that features separate and independent bias voltage sources for the main and auxiliary amplifiers. The bias voltage sources may be controllable and variable to alter the performance of the amplifier according to the input signal or system requirements. The enhanced amplifier includes a signal preparation unit to divide and shape the input signal in order to compensate for non-linearities in the combined output signal.

Disclosed is a Doherty amplifier which includes a carrier amplifier for always performing a signal amplification operation regardless of a level of an input signal, a peaking amplifier for performing an amplification operation, starting from a high power output where a level of an input signal is equal to or greater than a predetermined level, an output combination circuit for combining and outputting outputs of the carrier amplifier and the peaking amplifier, and an input division circuit for dividing an input signal into the carrier amplifier and the peaking amplifier, the Doherty amplifier including a carrier amplifier output harmonic impedance tuning network which is installed at a rear end of the carrier amplifier so as to tune an output harmonic impedance of the carrier amplifier, and a peaking amplifier output harmonic impedance tuning network which is installed at a rear end of the peaking amplifier so as to tune an output harmonic impedance of the peaking amplifier.

The disclosure relates to an enhanced Doherty amplifier that provides significant performance improvements over conventional Doherty amplifiers. The enhanced Doherty amplifier includes a power splitter, combining node, a carrier path, and a peaking path. The power splitter is configured to receive an input signal and split the input signal into a carrier signal provided at a carrier splitter output and a peaking signal provided at a peaking splitter output. The carrier path includes carrier power amplifier circuitry, a carrier input network coupled between the carrier splitter output and the carrier power amplifier circuitry, and a carrier output network coupled between the carrier power amplifier circuitry and the Doherty combining node.; The peaking path includes peaking power amplifier circuitry, a peaking input network coupled between the peaking splitter output and the peaking power amplifier circuitry, and a carrier output network coupled between the power amplifier circuitry and the Doherty combining node.

Provided is a distributed Doherty power amplifier exhibiting high efficiency and linearity at a wide range of bandwidths, the distributed Doherty power amplifier including a first amplifier; a second amplifier, which is connected to the first amplifier in parallel; a first shifting unit, which is interconnected between the input of the first amplifier and the input of the second amplifier and inverses the phase of the input of the second amplifier; and a second shifting unit, which is interconnected between the output of the first amplifier and the output of the second amplifier and inverses the phase of the output of the second amplifier, wherein the first amplifier and the second amplifier are Doherty power amplifiers, and each of the Doherty power amplifiers includes a carrier amplifier and a peaking amplifier, which are connected in parallel.

The invention provides a radio frequency power amplification device, which comprises a digital control circuit, a driver stage amplifier and a Doherty power amplifier, wherein the digital control circuit consists of a coupler, a signal power detection circuit and a grid voltage control circuit; and the digital control circuit adjusts the grid voltage of main power amplifiers in the driver stage amplifier and the Doherty power amplifier according to the signal power, so that the amplifier system has the optimal linearity. A signal amplification module consists of the driver stage amplifier and the Doherty power amplifier, wherein the driver stage amplifier is biased in AB classes and guarantees high linearity and gain; and the Doherty power amplifier guarantees high efficiency of the system. The radio frequency power amplification device is a high-efficiency high-linearity radio frequency power amplifier and is applied to a wireless communication transmitter.

A device including a Doherty amplifier, the Doherty amplifier having an amplifier input and output. At least one main amplifier is coupled to the input via a main input impedance and to the output via a main output impedance and additional amplifiers, each amplifier being coupled to the input via respective additional input impedances. Each additional amplifier has a respective additional amplifier output coupled to a respective pair of additional impedances connected in series and having a respective connection node between them. The device also has a first additional amplifier having their respective additional impedances coupled between its respective output and the amplifier output, the pair of additional impedances having first and second impedances, the first impedance being connected to the respective additional amplifier output and to the connection node, the second impedance being coupled between their respective connection node and the connection node of the previous additional amplifier.