351 results about "High power amplifier" patented technology

An embodiment of the invention uses a predistortion correction signal to combination the modulated RF signal by an analog multiplier for linearization of power amplifiers having nonlinear characteristics such as those used in wireless RF transmitters. A predistortion controller comprises a plurality of down converters for retrieving both the ideal non-distorted information and the feedback distorted information, together with pre-stored digitally-indexed predistortion information stored, for example, in a look-up table. The digitally-indexed information models nonlinear characteristics of the high power amplifier, and is stored prior to processing of pre-compensation in the power amplifier. When the predistortion information is combined with the modulated RF signal in the analog multiplier, the result is a substantially linear information transmission from the power amplifier. In an embodiment of the system, the modulated RF input signal and the feedback signal from PA output are down-converted, respectively, by analog devices, such as mixers, after which the analog intermediate frequency (IF) signals are digitized by analog-to-digital converters for digital predistortion correction processing, followed by predistortion processing performed by, for example, a DSP or FPGA chip to generate a digital correction control signal, which is then converted to an analog signal by a digital-to-analog converter, followed by combining the analog correction signal with the RF modulated input signal to yield the input to the power amplifier.

A wired relay method for using a remote station and an apparatus thereof for a Radio over Fiber (RoF) wired relay system supporting a Time Division Duplexing (TDD) wireless communication service, which shares an Low-Noise Amplifier (LNA) for both uplink and downlink operations. The remote station includes a block for dividing each of a downlink optical signal carrying service data and an optical signal carrying transmission / reception control information of the RoF wired relay system, which are input from a base station, a gain controller for separating an uplink Radio Frequency (RF) signal input from an antenna or a portion of a downlink RF signal output from a High-Power Amplifier (HPA) and for monitoring the strength of the input and output RF signals in order to control a gain of the LNA. A converter mutually converts an optical signal and an RF signal, an amplifier amplifies the converted RF signal, and an RF signal flow controller automatically controlls uplink and downlink transmission paths of the amplified RF signal according to a transmission / reception status of the RoF wired relay system.

Provided is an HPA apparatus for a TDD wireless communication system. In the HPA apparatus, a power amplifier amplifies the power of an input signal. A gate bias controller turns on / off a gate bias of the power amplifier in accordance with a TDD control signal. A constellation error optimizer circuit removes a current fluctuation and a power noise, which occur when the gate bias controller turns on / off the power amplifier in a TX mode, to stabilize a drain bias thereof.

A technique for converting a non-sectorized cell to a sectorized cell having multiple sectors utilizing a single broadband processing unit. The spectrum of a given frequency band having a center frequency 'OMEGAo is divided into multiple bands (three, for example) having center frequencies 'OMEGAo, 'OMEGAo-alpha and 'OMEGAo+alpha. In the receive path, respective sub-bands are used to convey analog RF signals from a subscriber in respective sectors to an associated transceiver. Each of the transceivers includes a front end for receiving incoming RF signals and an analog-to-digital converter for converting the analog signal to a digital data stream. The digital data streams from transceivers are combined, i.e., processed by digitally adding, and supplied to a single channelizer which, in turn, supplies the data to a TDM bus for transmission to a PSTN network. In the reverse path from the PSTN network, TDM digital data signals emanating from a TDM bus are supplied to a combiner which feeds each of the respective transceivers which select the appropriate data from the combiner by digital filtering or processing. The transceivers convert the digital signal to analog form. After conversion, power amplifiers associated with the respective sectors effect emission of radiated power in the respective sectors. Advantageously, amplifiers in the sectorized improvement operate at lower power levels than the single high power amplifier of a non-sectorized cell, thereby providing substantial cost savings. More importantly, instead of deploying multiple broadband processing units the improved sectorized cell requires only a single broadband processing unit, thereby providing further economies.

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.

An electronically scanned array antenna. The novel antenna includes a first planar array of antenna elements and one or more side planar arrays of antenna elements, each side array adjacent to the first array and tilted at a predetermined angle relative to the first array. In an illustrative embodiment, the antenna also includes a plurality of transmit / receive modules, each module coupled to one antenna element. Each transmit / receive module includes phase shifters for varying the relative phases of the antenna elements to form a desired overall beam pattern, and a low noise amplifier and high power amplifier for amplifying signals received and transmitted by the antenna element, respectively. In an illustrative embodiment, a processor provides individual phase and channel enable control signals for independently controlling the phase shifters and amplifiers, respectively, of each module.

A new class of 16-ary Amplitude and Phase Shift Keying (APSK) coded modulations, called double-ring APSK modulation, based on an amplitude and phase shift keying constellation in which the locations of the digital signals to be encoded are placed on two concentric rings of equally spaced signal points. The APSK constellation parameters are optimised so as to pre-compensate the impact of non-linearities. The new modulation scheme is suited for being used with different coding schemes. It is shown that, for the same coding scheme, pre-distorted double-ring APSK modulation significantly outperforms classical 16-QAM and 16-PSK over a typical satellite channel, due to its intrinsic robustness against the high power amplifier non-linear characteristics. The proposed coded modulation scheme is shown to provide a considerable performance advantage for future satellite multi-media and broadcasting systems.

Disclosed herein are circuits, devices and methods that address challenges associated with power amplifier systems. A power amplifier system includes two or more fast error amplifiers coupled to corresponding power amplifiers. The fast error amplifiers are configured to generate envelope tracking signals based on a signal envelope, the envelope tracking signals modifying a DC-DC regulated voltage from a DC-DC converter to more efficiently operate the power amplifiers. By splitting the envelope tracking between two or more fast error amplifiers and amplification between corresponding two or more power amplifiers, the power, frequency or bandwidth, linearity, signal-to-noise ratio, efficiency, or the like of the power amplifier system can be improved. Wireless communications configurations with such power amplifier systems can provide uplink carrier aggregation and / or cellular signals based on standards and protocols that require increased bandwidth and / or power.

A new class of 16-ary Amplitude and Phase Shift Keying (APSK) coded modulations, called double-ring APSK modulation, based on an amplitude and phase shift keying constellation in which the locations of the digital signals to be encoded are placed on two concentric rings of equally spaced signal points. The APSK constellation parameters are optimised so as to pre-compensate the impact of non-linearities. The new modulation scheme is suited for being used with different coding schemes. It is shown that, for the same coding scheme, pre-distorted double-ring APSK modulation significantly outperforms classical 16-QAM and 16-PSK over a typical satellite channel, due to its intrinsic robustness against the high power amplifier non-linear characteristics. The proposed coded modulation scheme is shown to provide a considerable performance advantage for future satellite multi-media and broadcasting systems.

A transmitter providing a wide output control variable width with high efficiency is provided. Saturation mode operation is performed in the vicinity of the maximum transmission power and the input level of a large power amplifier is enlarged and fixed. When the large power amplifier is operated in a saturation state, the amplitude component of a modulation signal is input to an R input terminal in the range responsive to an output power control level and power supply voltage of a power supply terminal is amplitude-modulated, whereby highly efficient polar coordinate modulation is performed. In smaller transmission power, linear mode operation is performed, the input level of the large power amplifier is lessened for operating the large power amplifier in the linear mode, and the power supply voltage of the power supply terminal is made variable in response to the output power control level, whereby transmission power control is performed.

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 high power Doherty RF amplifier utilizes multi-stage amplifier modules for both the main amplifier and the peak amplifiers. In one embodiment of a two way two stage amplifier, the first stage of each amplifier module can include signal pre-distortion whereby the first stage compensates for distortion in both the first and second stages. The design is simple and results in a high efficiency amplifier with high gain. In one embodiment, a commercially available CREE PFM19030SM power module is used in both the main amplifier and the peak amplifier.

A self-testing transceiver having an on-chip power detection capability is provided. The self-testing transceiver can include a semiconductor substrate and a transmitter having a high-power amplifier disposed on the substrate. The self-testing transceiver also can include a receiver disposed on the substrate for selectively coupling to an antenna. The self-testing transceiver can further include at least one power detector disposed on the semiconductor substrate for determining a power such as an RMS and / or peak-power of a signal at an internal node of the self-testing transceiver. Additionally, the self-testing transceiver can include a loopback circuit disposed on the substrate.