44 results about "Third order intermodulation distortion" patented technology

Methods and apparatus are provided for substantially reducing and / or canceling nonlinearities of any order in circuits, devices, and systems such as amplifiers and mixers. In particular, methods and apparatus are provided for substantially reducing and / or canceling third order nonlinearities in circuits, devices, and systems such as amplifiers and mixers. A first coupler is used to split an input signal into two equal-amplitude in-phase components, each component is processed by two nonlinear devices with different nonlinearities, and a final combiner, such as a 180-degree hybrid, recombines the processed signals 180 degrees out of phase and substantially reduces and / or cancels the undesired nonlinear distortion components arising due to nonlinearities in the nonlinear devices.

A predistortion method for CMOS Low-Noise-Amplifiers (LNAs) to be used in Broadband Wireless applications is presented. The method is based on the nulling of the third order Intermodulation distortion (IMD3) of the main amplifier by a highly nonlinear predistortion branch. Maximum third order product cancellation is ensured by a transformer feedback method. The technique improves linearity in a wide range of input power without significant gain and Noise Figure (NF) degradation. Simulation results on a 1-V LNA indicate a 10.3 dB improvement in the Input Third-Order Intercept Point (IIP3) with a reduction of only 1 dB and 0.44 dB in amplifier gain and NF respectively.

A power amplifier of the present invention includes a distributor (76) for distributing an input signal; an anti-phase third-order intermodulation distortion generation circuit (63) for, upon receiving the input signal that was distributed by the distributor, generating third-order intermodulation distortion for which the phase difference is anti-phase with respect to each of two main signals of different frequencies and supplying the two main signals and the third-order intermodulation distortion; a first amplifier (61) for amplifying the signal received from the anti-phase third-order intermodulation distortion generation circuit and supplying the result; a second amplifier (62) for amplifying the input signal that was distributed by the distributor and supplying the result; and a synthesizer (64) for combining the output signal of the first amplifier and the output signal of the second amplifier.

A distortion compensating circuit for a power amplifier attains raised compensating accuracy with shorter convergence time by accurately and quickly generating a distortion compensation signal for pre-distortion. An error signal representing the difference between the input and output signals of the power amplifier is generated. From the error signal and the input signal, the coefficients of the third-order intermodulation distortion, fifth-order intermodulation distortion and seventh-order intermodulation distortion are calculated. According to these coefficients, a distortion compensating signal which is characteristically opposite in phase and gain to the intermodulation distortions is generated.

A distortion compensating circuit for a power amplifier attains raised compensating accuracy with shorter convergence time by accurately and quickly generating a distortion compensation signal for pre-distortion. An error signal representing the difference between the input and output signals of the power amplifier is generated. From the error signal and the input signal, the coefficients of the third-order intermodulation distortion, fifth-order intermodulation distortion and seventh-order intermodulation distortion are calculated. According to these coefficients, a distortion compensating signal which is characteristically opposite in phase and gain to the intermodulation distortions is generated.

A low noise amplifier includes a main amplifier configured to amplify a first input signal to generate a first output signal and an auxiliary amplifier configured to amplify a second input signal to generate a second output signal. The auxiliary amplifier is coupled to the main amplifier for superposing the second output signal and the first output signal. The low noise amplifier also includes an adjusting unit configured to adjust a time constant for reducing a third order intermodulation distortion of the superposed signal in response to a control signal. The adjusting unit is configured to generate the second input signal based on the time constant and the first input signal.

A multistage amplifying device for amplifying a desired signal comprise first to N-th amplifiers connected in cascade,wherein the k-th (k is 1 to N) amplifier includes a k-th amplification section; and a k-th feedback section which has a reactance component, changes a phase of a signal output from the k-th amplification section. When a phase difference between the desired signal output from the N-th amplifier and a third-order inter-modulation distortion(IM3) output from the (N−1)-th amplifier is referred to as a first phase, and a phase difference between the desired signal output from the N-th amplifier, and a combined IM3 obtained by combining a IM3 occurring in the N-th amplification section and a IM3 fed back from the N-th feedback section is referred to as a second phase, a difference between the first phase and the second phase is 120° or more and 180° or less.

Provided is a signal amplification apparatus with advanced linearization, the signal amplification apparatus including: a driving unit having a structure of a cascode amplifier including a first active element and a second active element and outputting an amplification signal in which an input signal is amplified, to an output terminal; a third active element receiving a signal diverged between the first active element and the second active element while gate and drain terminals of the third active element are shorted; a fourth active element of which gate and drain terminals are connected to a source terminal of the third active element; and a fifth active element of which gate terminal is connected to the drain terminal of the fourth active element, outputting a non-linear signal having an opposite phase to the amplification signal to the output terminal so as to cancel a third-order inter-modulation distortion component included in the input signal. An amplification signal in which an input signal is amplified is combined with a non-linear signal having an opposite phase to the amplification signal and a low gain and is output so that a third-order inter-modulation distortion component included in the input signal can be cancelled and a signal with advanced linearity can be output.

The invention relates to an automatic testing method of mixer third-order intermodulation distortion inside a radio frequency tuner chip, in particular to an automatic testing method of mixer third-order intermodulation distortion inside a DVB-C digital television tuner chip. The automatic testing method adopts the radio frequency apparatus made by Agilent Company as the testing platform. The mainequipment of the testing method comprises an Agilent spectrum analyzer E4402B, an Agilent vector signal generator E4438C, an Agilent digital power supply E3649A, an Agilent GPIB link module 82357A anda computer. By means of the IEEE488 communication protocol, the programmable apparatus standard command (SCPI) and chip I<2>C control protocol, test software controls the operating state of the chipa nd sets and reads relevant parameter of a testing apparatus through the read-write operation of a register arranged inside a tuner chip, thereby realizing automatic radio frequency testing. In addition, the test software consists of an IEEE488 drive module, a parallel port drive module, an I<2>C module and a mixer test module.