348 results about "High power amplifier" patented technology

A method for a combined adaptive digital pre-distorter and pre-equalizer apparatus in single- and/or multiple-link hopping radio systems including hopping among a plurality of radio links to transmit variable-length bursts of radio signals on the plurality of radio links. Further, pre-distorting amplitude and phase of transmitted signal constellations based on the inverse AM-to-AM and AM-to-PM characteristics and the operating conditions of the high-power amplifier, respectively. Further, pre-equalizing amplitude and group-delay variations of the transmit RF radio using the pre-stored estimated complex tap coefficient of the pre-equalizer under different frequency bands.

High-speed silicon CMOS circuits and high-power AlGaN/GaN amplifiers are integrated on the same wafer. A thin layer of high resistivity silicon is bonded on a substrate. Following the bonding, an AlGaN/GaN structure is grown over the bonded silicon layer. A silicon nitride or a silicon oxide layer is then deposited over the AlGaN/GaN structure. Following this, a thin layer of silicon is bonded to the silicon nitride/silicon oxide layer. An area for the fabrication of AlGaN/GaN devices is defined, and the silicon is etched away from those areas. Following this, CMOS devices are fabricated on the silicon layer and AlGaN/GaN devices fabricated on the AlGaN/GaN surface.

A linear compensation system of a digital TV relay or other apparatus preferably includes a transmitting unit configured to modulate a data to an intermediate frequency (IF) signal, up convert the IF signal to an RF signal, and amplify the RF signal to a predetermined level using a high power amplifier (HPA). The system also includes a linear compensation unit to preferably directly vary a step size of an adaptive equalizer according to whether a signal-to-noise ratio (SNR) or an error vector magnitude (EVM) for an output signal of the HPA satisfies an advanced television systems committee (ATSC) or other standard. The linear compensation unit is thus configured to output an improved linear compensation coefficient to a modulator of the transmitting unit.

An improved communication system and method employing an actively controlled antenna array architecture is disclosed. The array contains a plurality of driven radiating elements that are spatially arranged having a pair of radiating elements fed with an RF signal predistorted so as to provide a controlled variation of the antenna array's elevation radiation pattern. High power amplifier (PA) efficiency is maintained by adaptive predistortion, coupled to each high power PA, while providing beam tilt and side lobe control.

The invention provides an adaptive digital pre-distortion technique and device which is suitable for OFDM projector. The device comprises an OFDM baseband signal module for orthogonal frequency division multiplexing technique, a digital pre-distortion synthetic process component, an analog and digital converter DAC, a radio frequency projector, a wideband high power amplifier, i.e., W-HPA, and a feedback circuit. Wherein, a digital pre-distortion internal core, which is structured in polynomial mode, implements pre-distortion process to the digital signals which have undergone signal pre-process; the estimate and uploading to an adaptive digital pre-distortion filter is implemented, based on hybrid algorithm which is the combination of training-sequence-based RLS+LMS algorithm or hybrid algorithm which is the combination of training-sequence-based QRD-RLS+NLMS algorithm. The invention can efficiently reduce the performance degradation of a wideband power amplifier caused by memory effect, improve the projecting performance of a base station system, and improve the linearity and the efficiency of the wideband power amplifier.

An optical parametric oscillator (OPO) is described that efficiently converts a near-infrared laser beam to tunable mid-infrared wavelength output. In some embodiments, the OPO includes an optical resonator containing a nonlinear crystal, such as periodically-poled lithium niobate. The OPO is pumped by a continuous-wave fiber-laser source having a low-power oscillator and a high-power amplifier, or using just a power oscillator). The fiber oscillator produces a single-frequency output defined by a distributed-feedback (DFB) structure of the fiber. The DFB-fiber-laser output is amplified to a pump level consistent with exceeding an oscillation threshold in the OPO in which only one of two generated waves (“signal” and “idler”) is resonant within the optical cavity. This pump source provides the capability to tune the DFB fiber laser by straining the fiber (using an attached piezoelectric element or by other means) that allows the OPO to be continuously tuned over substantial ranges, enabling rapid, wide continuous tuning of the OPO output frequency or frequencies.

A system for linearizing the output of a high power amplifier (HPA) designed to transmit an RF modulated signal includes in its transmit section a digital up-converter for processing baseband input signals and generating a desired digital RF waveform, T(s). The desired digital RF waveform T(s) is then fed to a digital predistorter circuit for producing a predistorted digital RF waveform P(s)T(s) which, as modified, may be applied via a high sampling speed high linearity digital to analog converter to the high power amplifier (HPA) to produce an output signal which is a linear function of the baseband input signal. The digital predistorter circuit may be of the adaptive type or of the predictive type. Circuits embodying the invention may include encoding circuitry for converting multi-bit signals to a serial stream of single-bit pulses for enabling simplification in the digital to analog conversion. In accordance with the invention, corrections for non-linearity of the HPA may be made directly on the RF waveform using ultra-high speed superconducting electronics (SCE) and decreasing the time delay between sensing a transmitted signal and generating a correcting (linearizing) signal.

Methods and systems for calculating pre-distortion coefficients in a closed-loop communication system are presented. Transmission terminals that include high power amplifiers are difficult to operate at or near the saturation point without transmitting signals with nonlinear distortions. By pre-distorting the signal prior to amplification the transmitted nonlinear distortions may be decreased. A closed-looped pre-distortion system may include a receiver that calculates the pre-distortion coefficients and transmits these coefficients back to the transmitter. These coefficients may be stored in a pre-distortion coefficient lookup table and may be updated by the receiver terminal.

A transmitter apparatus that exhibits a high efficiency and that can provide a wide variable output control width. An operation of saturation mode is performed in the vicinity of the maximum transmission power. A large-power amplifier (12) is caused, by increasing and then fixing the input level thereof, to operate in a saturation state, while the amplitude component of a modulation signal in a range corresponding to an output power control level is inputted to an R-input terminal (33) to amplitude modulate the power supply voltage (VDD) of a power supply terminal (25), thereby performing a polar coordinate modulation of a high efficiency. An operation of linear mode is performed for a smaller transmission power. The large-power amplifier (12) is caused, by reducing the input level thereof, to perform a linear operation, while the power supply voltage (VDD) of the power supply terminal (25) is varied in accordance with the output power control level, thereby performing a transmission power control.

An RF PA operable in two or more selectable power ranges is disclosed. Switches configure the circuit for each range such that an amplifier device corresponding to the range provides final amplification, and all lower power amplifier devices also amplify the signal. An exemplary design includes a low power amplifier configurable for operation solo, or in parallel with a medium power amplifier, to deliver an appropriately matched signal either directly to the RF PA output, or first to the input of a high power amplifier for the highest power range. The signal in all ranges of the exemplary design is conditioned in part by the matching circuitry disposed between the high power amplifier and the RF PA output, which traverses no switches in high power range operation. The entire RF PA, including switches, control and matching circuitry, is fabricated on a single monolithic integrated circuit, an achievement may be facilitated by UTSI CMOS processing.

A multi-channel and multi-carrier Digital Predistortion writing machine of wideband CDMA base station system includes the feedback signal processing channels and at least one multiplexing signal processing channels of multi-carrier base band, of which, each includes the digital base-band peak-clipping frequency processor, digital predistortion processing module, high-intermediate frequency output module and filter, radio frequency access and high power amplifier. The feedback signal processing channel includes the RF feedback channel and A/D converter. The invention uses the base band peak-clipping technology, digital predistortion technology and high-intermediate digital IF technology, to reduce the high cost by the use of the linear power amplifier, and can effectively enhance the launch performance and efficiency of the base station system. The invention does not use the feedback channel switching technology to achieve saving the cost of RF link.

A fiber laser cavity that provides a new pulse shaping and spectral shaping technique is disclosed in this invention to achieve the purpose of resolving the difficulties arising from the issues related to Q-switched solid state lasers. The laser system achieves high repetition rate (1 kHz-100 kHz) and high pulse-to-pulse energy stability with small timing jitter of the laser pulses and scalable to the Joule pulse energy level. The laser system of this invention employs new approach with a hybrid fiber/waveguide master Oscillator-High Power Amplifier (MOPA) laser system in combination with the pulse shaping technology that allows not only to scale the fiber laser pulse energy to the multi-Joule level with high pulse-to-pulse energy stability but also achieve precise control of laser pulse timing jitter in a scale of <100 ps that is at least 5 to 10 time more accurate than for Q-switched systems where the same parameter reaches 500-1000 ps range.

A high power amplifier has a first balun propagating a half of an input signal to an in-phase output terminal, and also propagating a fourth of the input signal to first and second opposite-phase output terminals, the signal propagated to the first and second opposite-phase output terminals lagging 180 degrees behind the signal propagated to the in-phase output terminal; first and second power amplifier circuits connected to the first and second opposite-phase output terminals of the first balun and having the same characteristics; a third power amplifier circuit connected to the in-phase output terminal of the first balun and having output power substantially twice as much as the output power of the first or second power amplifier circuit; and a second balun having first and second opposite-phase input terminals for receiving the outputs of the first and second power amplifier circuits, having an in-phase input terminal for receiving the output of the third power amplifier circuit, combining the outputs of the first, second and third power amplifier circuits, and propagating combined output.

Whitespace devices can use unused television frequencies for transmission and reception of WiFi OFDM signals. Three contiguous bands, such as former channels 2, 3, and 4, may be bonded together to define a whitespace band. In order to fit a WiFi OFDM signal into this whitespace band, a whitespace device compresses the bandwidth of each WiFi OFDM signal using a specific spectrum mask. Very low transmission power is needed for the modified WiFi OFDM signals, eliminating the need for high power amplifiers and most of the WiFi OFDM designs such as PHY and MAC can be reused with minor modifications.

A power amplifier comprises a distributed pre-driver, digital signal adjuster, a distributed high power amplifier; and an integrated coupler-detector unit. The distributed pre-driver, the digital signal adjuster, the distributed high power amplifier and the integrated coupler-detector unit are formed at an interface of a Gallium Nitride layer and an Aluminum Gallium Nitride layer of a monolithic microwave integrated circuit device.

The invention provides a multi-input multi-output (MIMO) terminal and a radio-frequency emission method thereof. The terminal comprises a first antenna, a radio-frequency emission module and a predistortion treatment module, wherein the radio-frequency emission module comprises a power amplifier which is connected with the first antenna and used for carrying out digital-to-analogue conversion and modulation on an input signal and power amplification on a modulated signal through the power amplifier and emitting the amplified signal through the first antenna; the predistortion treatment module is connected with the input end of the radio-frequency emission module and used for acquiring a predistortion coefficient corresponding to the output power of the power amplifier from a preset predistortion coefficient lookup table before the input signal is input to the radio-frequency emission module when the power amplifier works in a nonlinear area and carrying out predistortion treatment on the input signal according to the acquired predistortion coefficient. The power amplifier in the radio-frequency emission module of the MIMO terminal has improved linear performance and can meet the requirement on high power amplifier linearity of the LTE.

The invention discloses a high and low power combination circuit of a radio frequency power amplifier. The high and low power combination circuit is connected between an output signal and a load and comprises a high-power amplifier as a power level, a low-power amplifier and a control circuit, wherein the high-power amplifier and the low-power amplifier are connected in parallel, the control circuit is used for switching the two amplifiers to work and controlling the two amplifiers, the high-power amplifier and the low-power amplifier are connected with another amplifier as an output signal driving level, and the control circuit is used for controlling the continuous conduction of the driving-level amplifier and outputting bias current which is suitable for a high or low power working mode of the power level amplifier. In the high and low power combination circuit, the radio frequency power amplifier shares a driving level under the high and low power modes, simplifies inputting and matching network design and reduces the design difficulty of the circuit; and the high and low power combination circuit has the high and low power working modes, eliminates the efficiency influence ofthe low power mode by switch insertion loss through reasonably controlling the on-off of a radio frequency switch, effectively increases the average efficiency of the radio frequency power amplifierand prolongs the service life of batteries.