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8798198 Calibration systems for wireless electronic devices  
A calibration system may be provided for calibrating wireless communications circuitry in an electronic device during manufacturing. The calibration system may include data acquisition equipment...
8737939 Method and apparatus for detecting presence of an unmodulated RF carrier prior to a communication frame  
A measurement signal, the measurement signal indicative of a bias in a signal received via a communication channel, is generated. A detection signal, the detection signal indicative of presence of...
8509341 Communications device including a filter for notching wideband transmit signals and associated methods  
A communications device includes a modulator and a filter downstream therefrom and operable to generate an output wideband complex signal with a frequency notch therein. The filter includes a...
8269572 Reducing the distortion of applied modulation  
Signal modulation apparatus for applying a modulation signal to a carrier signal, the apparatus comprising: an amplitude modulator for modulating the amplitude of the carrier signal in accordance...
8259779 Method and apparatus with notched transmit frequency bins  
A wireless network (20) with at least a first radio communication unit (24) and a second radio communication unit (26) transmits and receives signals with minimal interference from the surrounding...
8121215 Broadband self adjusting quadrature signal generator and method thereof  
Low noise phase quadrature signals are generated after receiving a clock signal and adjusting the clock signal in response to a feedback signal to generate a phase adjusted clock signal. The clock...
8032095 Method and apparatus for detecting carrier leakage in a wireless or similar system  
A method and circuit for indicating signal faults in wireless transmissions, particularly, a carrier leak, includes an input to receive a wireless signal, a bias detector that detects a bias in a...
7995674 Digital predistortion transmitter  
There is a need for effectively compensating distortion when a predistortion transmitter is subject to not only a memory effect due to nonlinearity of an amplifier, but also a modulator's DC...
7893787 DC offset cancellation circuit for modulator using 1-bit signal conversion  
A DC offset cancellation circuit used for compensating a carrier leak at an output signal of a modulator has a sign extraction unit for extracting sign of an information signal which is applied to...
7864874 OFDM communications system employing crest factor reduction with ISI control  
A system and method for providing a peak power reduced OFDM communications signal are disclosed. The system and method provide peak reduction processing in the time domain followed by inter-symbol...
7864882 Method and apparatus for generating constant envelope modulation using a quadrature transmitter  
A multi-mode communication device (100) uses a quadrature transmitter (102) for transmitting both amplitude and constant envelope angle-modulated signals. For angle modulation, a separate feedback...
7769103 Amplifier system employing analog polynomial predistortion with sub-nyquist digital adaptation  
A predistortion linearized amplifier system that uses analog polynomial based predistortion is disclosed. An analog polynomial function generator receives polynomial parameter updates from a...
7570127 Method and system for spur suppression in modulators  
An IF receiver receives a tapped portion of a modulated communication signal. A processor, local with respect to the IF receiver, receives an interrupt from a main processor instructing it to...
7471739 Advanced adaptive pre-distortion in a radio frequency transmitter  
The present invention is related to methods and apparatus that advantageously permit the more efficient use of an input range of an analog-to-digital converter used by an adaptive predistortion...
7460611 Communication system, transmitting apparatus and transmitting method, receiving apparatus and receiving method, unbalance code mixing method and multiple code decoding method  
A transmitting station side transmits a transmitting signal obtained by a process of segmenting transmission information into a plurality of frames, of encoding each frame, of power amplifying...
7382887 Method and device for reducing high frequency error components of a multi-channel modulator  
A method and device for reducing error components of a multi-channel modulator. The method comprises the steps of inverting substantially half of the channels of a modulator, and reducing error...
7187911 Calibrated PLL for wide band communication semiconductor integrated polar loop transmitter  
The invention provides a communication semiconductor integrated circuit (RF IC) that, when a transmission oscillator is incorporated into a semiconductor chip, secures the oscillation operation...
7127020 Frequency synthesis loop having controlled loop gain  
A method and apparatus for generating a burst FSK signal having precisely shaped transitions between modulation states. The apparatus uses feedforward compensation of phase gain and phase...
7123665 Method and apparatus for measuring phase error of a modulated signal  
A method and apparatus for generating a burst FSK signal having precisely shaped transitions between modulation states. The apparatus uses feedforward compensation of phase gain and phase...
7123666 Gaussian minimum shift key transmitter with feedforward phase compensation  
A method and apparatus for generating a burst FSK signal having precisely shaped transitions between modulation states. The apparatus uses feedforward compensation of phase gain and phase...
7062236 Transmitter circuits  
A polar loop transmitter includes separate phase and envelope paths providing a linearising scheme for an efficient non-linear power amplifier. Loop filters are included in each of the phase and...
6924711 Multimode modulator employing a phase lock loop for wireless communications  
A phase-amplitude modulator for mobile communications employs a phase lock loop as an input to a nonlinear power amplifier providing phase information with amplitude information used to modulate...
6907085 Activation method of communications apparatus with a non-linear distortion compensation device  
First, a digital section constituting a linearizer is activated. Then, a feedback loop for updating a distortion compensation coefficient is opened. Then, the analog section on the antenna side is...
6844788 Polar loop transmitter  
A polar loop transmitter circuit arrangement includes a circuit input, a circuit output, a controllable signal source, a modulator connected between the signal source and the output, a first...
6657510 Corrective phase quadrature modulator system and method  
A system and method for producing a phase corrected M-QAM signal is described. In one embodiment, a phase-correcting M-QAM modulator comprises a feedback loop for dynamically adjusting the phase...
6614854 System and method for adaptive predistortion  
Distortion introduced into a multiamplitude signal format or amplitude and phase signal format by a high power microwave amplifier is compensated by a system which adapts itself to non-linearities...
6567478 Radio apparatus having distortion compensating function  
In a radio apparatus which compensates for non-linear distortion of a transmission power amplifier, a distributor feeds back the output signal of the transmission power amplifier, an error-signal...
6518849 Dynamic delay compensation versus average switching frequency in a modulator loop and methods thereof  
The present invention monitors the average switching frequency at the output of the comparator and adjusts the delay compensation accordingly. That is, the switching frequency monitoring circuit...
6414560 Loop delay compensation for a digital power amplifier  
A modulator loop is described having an associated band pass frequency range and including a switching stage having a first delay associated therewith. The modulator loop also includes a modulator...
6373346 Laser driver pre-emphasis and de-emphasis method and/or architecture with tuning and duty cycle control  
An apparatus comprising a modulator circuit, a first and a second control circuit. The modulator circuit may be configured to generate a modulated differential output signal in response to a...
6362702 Controlled self-oscillation modulator and power conversion system using such a modulator  
A controlled oscillation modulator includes a comparator and a power amplification stage for pulse modulation, and a higher order oscillating loop comprising first feedback means (21) and first...
6285255 Adaptive compensation for carrier signal phase distortion  
Apparatus and method are presented for adaptively compensating for carrier signal phase distortion caused by amplitude modulating an RF carrier signal. A modulator-amplifier network receives an RF...
6169463 Quadrature modulator with set-and-forget carrier leakage compensation  
A quadrature modulator with set-and-forget carrier leakage compensation. The quadrature modulator comprises an in-phase and a quadrature branch. In the in-phase and quadrature branches, real-time...
6141390 Predistortion in a linear transmitter using orthogonal kernels  
A system for linearly transmitting an amplified output signal using predistortion is disclosed. The system uses a straight inverse modeling scheme with orthogonal predictor variables to more...
5909153 Method and apparatus for compensating for delays in modulator loops  
A modulator loop designed to operate in a frequency range of interest is described. The loop includes a loop output terminal and a switching stage, the output of which is coupled to the loop...
5900778 Adaptive parametric signal predistorter for compensation of time varying linear and nonlinear amplifier distortion  
A high power amplifier system includes an on-line adaptive predistorter for generating predistorted complex data signals to a high power amplifier in response to receiving incoming complex data...
5883551 Quadrature modulator malfunction estimator and modulator stage using it  
A quadrature modulator including two mixers to which two carrier signals are applied and to each of which a modulating signal is applied, output signals of the mixers being applied to a combiner...
5798674 Band Limited AM modulator using linear power amplification  
A band limited Amplitude Shift Keyed (ASK) modulator employing linear modulation and an efficient Class C power amplifier. Band-limited operation is provided by filtering a digital baseband input...
5768699 Amplifier with detuned test signal cancellation for improved wide-band frequency response  
A feed forward amplifier circuit which includes a main amplifier, an error correction circuit producing a message error signal, an error amplifier for producing an amplified message error signal...
5748678 Radio communications apparatus  
A radio communications apparatus employs a training routine for optimizing performance and has a modulator (64, 66) to modulate a radio channel with digital information, to provide baseband...
5719527 Method and apparatus for amplifying, modulating and demodulating  
A highly efficient linear amplifier and/or modulator and demodulator comprising first and second feedback loops is provided. Each loop processes a component of the input signal and the component...
5699383 High-power linear amplification using periodically updated amplitude and phase correction values  
In a high-power transmitter, an input complex signal is multiplied in a complex multiplier by control signals. The output complex signal from the multiplier is converted to a high frequency signal...
5663691 Estimator for estimating an operating defect in a quadrature modulator, and a modulation stage using the estimator  
An estimator for estimating an operating defect in a quadrature modulator, including two mixers to which respective carrier signals are applied, and to which respective modulating signals are also...
5661442 Amplitude control system having parallel integrating signal paths  
An amplitude control system uses a pair of parallel integrators to rapidly adjust the amplitude of a test signal between two precisely determined power levels in an RF signal generator. The...
5450043 Quadrature modulator with distortion compensation  
A quadrature modulator multiplies two carriers which are 90° out of phase with each other by a sine component and a cosine component of a baseband signal, respectively, adds the product signals to...
5396196 Quadrature modular with adaptive suppression of carrier leakage  
A carrier leakage suppression circuit is disclosed which adaptively suppresses carrier leakage in a signal processing device which modulates a carrier signal with an in-phase baseband signal and a...
5247542 QPSK power amplifier distortion correction system  
A quadrature phase-shift keying modulator produces a QPSK signal which is amplified by a power amplifier. The amplitude gain of the power amplifier is controlled in response to an amplitude...
5105164 High efficiency UHF linear power amplifier  
An RF amplifier for a phase and envelope varying signal employs a class C operated device for high efficiency. In order to improve the linearity of the class C operated device, a signal...
5095290 Amplitude modulator having negative feedback circuit for reducing distortion  
Modulator circuit (MOD) with a modulator proper and a correction signal generator. The modulator proper comprises the cascade connection of an amplifier (T11, T21, CS11, T12, T22, CS12) and a...
5012208 Quadrature modulator having compensation for local oscillator leak  
The invention relates to a quadrature modulator comprising a circuit for the compensation of a local oscillator leak signal in an output signal of the modulator, which circuit adds different...
Matches 1 - 50 out of 151 1 2 3 4 >