Abstract: Systems and methods are taught whereby amplification of narrowband signals may be accomplished by linear power amplifiers requiring the presence of a communicated broadband signal in order to make internal adjustments necessary for linear operation. A preferred embodiment is described utilizing an input of a distributed amplifier assembly unused by the signals of interest in order to inject an emulated CDMA tone operable as a pilot tone for use by the linear power amplifiers.

Abstract: The invention relates to an amplifier arrangement for amplifying an input using a distorting main power amplifier such as one operating as a class AB amplifier. The method and apparatus add to the input signal to the main amplifier a predistortion signal intended to compensate for the distortion added by the main power amplifier. In accordance with the invention, the input to the predistortion circuit is modified by measuring peak-to-peak signal values of the distortion in the output of the main power amplifier. The peak-to-peak values are measured in a signal derived by comparing an output derived from the main amplifier with an output derived from the input signal. A digitally controlled processor iteratively modifies various phase and gain controls to adjust the output of the amplifier.

Abstract: The invention relates to a method and apparatus for reducing the distortion output of an amplifier used with an RF signal. The method and apparatus typically modify the distortion of the amplifier to reduce it, by detecting cross-modulation components modulated onto a continuous wave, low level, pilot signal injected at the input of the amplifier system. The circuitry detects the cross-modulation components and provides correction signals in response thereto.

Abstract: The invention relates to a low cost feed forward RF power amplifier arrangement for amplifying an RF input signal using a main power amplifier operating as a Class AB amplifier. The method and apparatus modify the input signal to the main amplifier to compensate for the distortion added by the main power amplifier. The circuit provides for injecting a pilot signal prior to the Class AB amplifier and adjusting the correction circuitry of the amplifier based on a quadrature modulated, chopped derivative of the injected pilot signal.

Abstract: A method and apparatus reduce the out-of-band frequency components of an RF amplified signal, preferably a CDMA signal, which has a carrier frequency which is not known in advance. The apparatus and method feature locating the frequency of the incoming signal by examining an RF output signal having both in-band frequency components and out-of-band frequency components. Typically the output signal is generated using a high-power, Class A/B amplifier. Once the frequency of the carrier has been determined, the out-of-band components are used to generate control signals which, in, for example, a feedback or feedforward circuitry, reduce the energy of the out-of-band signals and thereby provide a more linear amplifier transfer function.

Abstract: A method and apparatus for reducing out-of-band frequency components of an RF amplified input signal, the amplified signal having both in-band frequency components and out-of-band frequency components, employ a feedforward network in which a microprocessor can sweep a frequency generator output connected to a mixer, the other input of the mixer being the amplified output, to find the carrier frequency of the input signal, and thereafter modify or control the feedforward circuit to reduce out-of-band frequency component energies in a particular manner. For example, gain and phase of a variable gain-phase network in a feedforward circuit structure can be modified for reducing the out-of-band frequency component energy.

Abstract: A method and apparatus for reducing out-of-band frequency components of an RF signal having a carrier frequency which is not known in advance employ a control signal to vary adjustable bias parameters of the circuit. In particular embodiments, the RF signal is generated from a MOSFET power amplifier, which introduces distortion components into its output signal. Bias parameters of the MOSFET amplifier can be varied to reduce out-of-band frequency components, that is, out-of-band distortion. In addition, other elements of the network can be controlled by varying bias parameters, for example, a predistorter.

Abstract: An apparatus and method measure the energy in frequency bands of an amplified signal, the amplified signal being an amplified version of an RF received input signal, where the received signal has an allocated frequency bandwidth and carrier frequency. The carrier frequency, however, is not known in advance of receipt; and therefore, the apparatus and method provide structure and methodology for finding the carrier and then reducing the out-of-band frequency components of the amplified signal. The apparatus features a mixer configured as a four quadrant multiplier biased into a linear operating region. The mixer receives both the received signal and the amplified signal, and produces as its output a baseband signal. Various detection mechanisms can be used to determine the distortion correction control signals based upon the energy in portions of the amplified signal offset from the carrier signal. In a preferred embodiment, the mixer is a Gilbert Cell mixer and the received signal is a CDMA signal.

Abstract: For use with RF circuitry in which a DC bias circuit provides bias voltage is provided to impedance-matched circuitry, a structure is provided, in which a dielectric member, having a high dielectric constant, is selectively placed adjacent to a bias feed line coupled between the DC bias circuit and the remainder of the circuitry, to maintain high RF impedance while reducing impedance at lower frequencies. The invention has particular applicability to RF amplifiers, to be used for amplifying modulated carriers, such as video signals made up of an RF carrier and a lower-frequency modulation. Where the carrier has a predetermined wavelength, the physical length of the bias feed line and the dielectric constant of the dielectric member are chosen such that an effective length of the bias feed line is a quarter of the wavelength of the carrier.

Abstract: The invention relates to an amplifier arrangement for amplifying an input using a distorting main power amplifier such as one operating as a class AB amplifier. The method and apparatus add to the input signal to the main amplifier a predistortion signal intended to compensate for the distortion added by the main power amplifier. In accordance with the invention, the predistortion signals can be dynamically modified to improve, substantially, at least the third order intermodulation components in the output of the power amplifier. A digitally controlled processor iteratively modifies various phase and gain controls to adjust the output of the amplifier. Different gain and phase control lines are iteratively updated at different rates.

Abstract: The invention relates to an amplifier arrangement for amplifying an input signal using a distorting main power amplifier such as one operating as a class AB amplifier. The amplifier can be biased at different operating points. The method and apparatus modify bias control signals to the main amplifier to reduce or minimize the distortion energy added by the main power amplifier. A digitally controlled processor iteratively modifies various control bias signals to adjust the output of the amplifier. Different gain and phase control lines can also be iteratively updated at different rates.

Abstract: A broadband feed-forward amplifier configuration includes an amplifier having an input and an output. A comparison loop compares the signal output to the amplifier with a signal input to the amplifier to generate an error signal and this error signal is inverted, processed, and amplified to provide a correction signal at the output of the amplifier (the cancellation loop). In the cancellation loop and at the input of the main amplifier, the circuit includes gain and phase correction circuitry for correcting small variations in amplitude and phase. A quadrature modulated pilot signal is injected at the input to the main amplifier path and is cancelled in the output to generate control signals for controlling the gain and phase correction circuits within the cancellation loop and within the main amplification loop.