Abstract: A system and method of compensating for the effects of the antenna coupling in on-frequency repeaters, whose input and output signals are the same frequency, are disclosed. The repeater is implemented with internal digitally determined compensation that reduces the effect of the antenna coupling, allowing the forward gain of the repeater to be increased. The real and imaginary components of the forward gain are dithered. The change in the power spectrum of the signal in response to the dithering is used to estimate the residual (uncompensated) feedback coupling.

Abstract: A single pole antenna array architecture provides an azimuth variable beamwidth. The array includes a number of driven radiating elements that are spatially arranged having a pivoting actuator so as to provide a controlled variation of the antenna array's radiation pattern.

Abstract: A control system for a linear feed-forward amplifier, using the ratio of measured spurious energy. Measuring receivers are coupled to two monitoring points to measure the spurious energy content in the error signal and at the main output of a feed-forward amplifier. The control system measures the ratio of these detected spurious, and uses this to optimize the settings of the second loop distortion cancellation. With the addition of an extra monitoring point, the same technique may also be used to control an adaptive predistorter prior to the main amplifier.

Abstract: The invention relates to a structure comprising an enclosed antenna system, and a radome (18), where the structure comprises: a tower (B, C), comprising a main tube (2) fastened on a bottom flange (7) of the tower (B, C), a smaller-diameter tube (5) which hooks within the main tube (2) and further is fastened on an upper flange (8) of the tower (B, C), a nut (6) fastened on the other end of said smaller-diameter tube (5), a rod (3) which screws on within the nut (6), a shaft (4) fastened at the bottom part of the rod (3) and terminating in a nut (1), where the radome (18) is fastened on the upper flange (8) of the tower (B,C), thus making it possible to check the antennas mounted on the main tube (2) by that when screwing the nut (1), the radome (18) is arranged to move upwards, making the bottom of the antenna system accessible.

Abstract: A method for forming flanged end of an inner conductor of a coaxial resonator at one end of the conductive body. The flange is formed integral to the conductive body by flaring the end of the conductive body. The size and shape of the flange are selected to achieve a desired capacitance surface area for use in a resonator. A combination of expanding tool and calibration tool are used to control the size and shape of the flange that will be formed on the end of the conductive body.

Abstract: A dual polarized broadband base station antenna for wireless communication systems is disclosed. The present invention employs a dual polarized boxed arrangement radiation element with high isolation between polarization channels. Plural radiating elements project outwardly from the surface of a ground plane. The antenna elements are paired dipoles.

Abstract: A system and method for controlling the gain in the forward signal path of a digital predistortion linearizer is disclosed. The loop gain of the predistortion system is driven to unity, where a separately controlled constant-gain observation path allows accurate gain control of the forward path. This is divided into digital gain from the predistortion function and analog gain from a Voltage Variable Attenuator (VVA) in the transmitter. The invention balances the distribution between these two domains in order to maximize dynamic range and minimize noise in the forward signal path. In order to distribute the forward path gain accurately, the characteristic of the VVA must be well known. Since these devices tend to be non-linear, with variable characteristic over temperature and batch, the invention compensates for this non-linear behavior by tracking the varying transfer characteristic of the VVA, giving a predictable local characteristic.

Abstract: A system and method of digitally predistorting a transmitter that has a digital input, up-converter, and a RF amplifier is disclosed. A digital predistorter preferably employs three paths for the digital input signal: a linear path, a memoryless digital predistortion path, and a memory based digital predistortion path. The memoryless path is preferably a look up table (LUT) of gain error corrections indexed to the input magnitude or input power. The linear path is separated to preserve the dynamic range of the system and avoid quantization associated with memoryless LUT correction. The memory based digital predistortion path filters the power envelope, or higher even order modes of the input signal magnitude, employing a hierarchical filter, to produce a gain correction. The input signal is modulated by the gain error corrections produced by the memoryless and memory based paths.

Abstract: An improved vault that facilitates the underground storage of electronic equipment, such as instrumentation for wireless telecommunications antenna systems. The vault preferably includes an air lock cover that prevents the electronic equipment from being submerged under water when the vault floods.

Abstract: A method and apparatus of transmitting a communication signal between a radio base station and a radiation element. In one embodiment, the method includes receiving an input signal. Then extracting a data signal from the input signal, the data signal includes values representing operating parameters of devices at the radiation element. And producing a status signal for each device that simulates a feedback signal for the device.

Abstract: 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.

Abstract: A high power, low loss RF strip transmission line coupling structure is provided. It includes a multi-layer printed circuit board (PCB), a top cover and a bottom cover. The top and bottom covers provide the ground reference for the strip transmission line coupling structure. The PCB is fastened to the top and bottom covers and is used for: creating the center conductor of an air dielectric strip transmission line and edge coupler; providing a means to transition from microstrip to air dielectric strip transmission line; supporting the air dielectric strip transmission line; routing of other signals; and passing ground to the top and bottom covers. To create an air dielectric strip transmission line, the PCB material is adequately removed to effectively form a rectangular bar of dielectric and metal layers. This rectangular bar is plated along the edges where the PCB material was removed to ensure that the top and bottom PCB metal layers are at the same potential.

Abstract: A system for linearizing RF amplifiers employing baseband predistortion techniques provides additive or multiplicative predistortion of the quadrature (I/Q) input signal. The predistorter uses a discrete-time polynomial kernel to model the inverse transfer characteristic of the amplifier, providing separate and simultaneous compensation for nonlinear static distortion, linear dynamic distortion and nonlinear dynamic effects including reactive electrical memory effects. A predistortion controller monitors and compares the amplifier output with the quadrature input signal to compute estimates of the residual output distortion of the amplifier. Output distortion estimates are used to adaptively compute the predistorter parameter values in response to changes in the amplifier's operating conditions. The computed values are used in the predistorter.

Abstract: A digital predistortion system and method employing parallel signal paths is disclosed. A first primary signal path receives a rectangular (I,Q) input signal and provides it to an additive predistortion correction circuit. A second parallel signal path includes coordinate rotation circuitry and a predistortion coefficient look up table. Any effects of calculational errors on the primary input signal are minimized by avoiding manipulations of the input signal in the primary signal path. A third parallel signal path may be used to receive the input signal for calculating adaptive updates to the look up table entries.

Abstract: An RF amplifier assembly employing a finned heat sink and a heat pipe enhanced aluminum pallet is disclosed. The hybrid heat pipe enhanced aluminum pallet reduces the spreading thermal conduction resistance associated with the conduction of localized energy from RF amplifier devices when compared to a copper pallet. The localized energy concentration of RF amplifier devices is spread along the length of the heat pipe increasing the overall efficiency of the heat sink coupled to the pallet and accommodating non-uniform heat loading. This reduces the junction temperature of the devices, which leads to higher mean time before failure and higher output levels. The pipes are formed and embedded into the pallet so as to pass under different areas of interest and extend to the under-utilized regions.

Abstract: 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.

Abstract: A system for digitally linearizing the nonlinear behaviour of RF high efficiency amplifiers employing baseband predistortion techniques is disclosed. The system provides additive or multiplicative predistortion of the digital quadrature (I/Q) input signal in order to minimize distortion at the output of the amplifier. The predistorter uses a discrete-time polynomial kernel to model the inverse transfer characteristic of the amplifier, providing separate and simultaneous compensation for nonlinear static distortion, linear dynamic distortion and nonlinear dynamic effects including reactive electrical memory effects. Compensation for higher order reactive and thermal memory effects is embedded in the nonlinear dynamic compensation operation of the predistorter in an IIR filter bank. The digital predistortion system of the invention may provide broadband linearization of highly nonlinear and highly efficient RF amplification circuits including, but not limited to, dynamic load modulation amplifiers.

Abstract: A delay mismatched feed forward power amplifier is disclosed. Loop 1 includes a main amplifier and is used to derive a carrier cancelled sample of the main amplifier output. Loop 2 includes an error amplifier used to amplify the carrier cancelled signal derived from Loop 1 operation in order to cancel distortion products generated due to the nonlinear nature of the main amplifier. Loop 2 also utilizes a very short Loop 2 delay line. A significant efficiency gain is provided due to reduced output power losses associated with the Loop 2 delay 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.

Abstract: An adaptive predistortion linearized amplifier system employing selective sampling is disclosed. Two selective sampling methods of identifying valid measurements using information from the input signal are disclosed. The selective sampling process improves the convergence properties of tuning algorithms based on minimizing the gain error variance. It also reduces the number of data samples processed by the estimator used in the tuning process.

Abstract: A method and apparatus for digital predistortion of power amplifiers are disclosed. Successful digital predistortion parameter settings are correlated with the operating conditions that affect the distortion of an amplifier. These operating conditions may include input power level, carrier frequency, temperature, DC supply voltage, or others. The successful predistortion parameter settings along with the corresponding operating conditions are stored in a list that is indexed using multi-dimensional attribute vectors. The elements of the list are generated automatically.