Panasonic Corporation

Matsushita Electric Industrial Co., Ltd.

Matsushita Electric Industrial

Tropian, Inc.

Wayne S Lee

Toru Matsuura

Gary Lang Do

Akihiko Matsuoka

Tomoya Urushihara

Kenichi Mori

Tony L Wong

Earl W McCune

Kan G Hoy

Toshifumi Nakatani

Akira Kato

Thomas E Biedka

Herb Evans

A transmitter includes: a decoder for transforming an IQ signal into a linear sum of two vectors which have non-negative coefficients, respectively, which form an angle of (&#x3c0;/4), and which are included in eight vectors representing directions indicated by eight angles of (&#x2212;&#x3c0;/2), 0, (&#x3c0;/2), &#x3c0;, (&#x2212;3&#x3c0;/4), (&#x2212;&#x3c0;/4), (&#x3c0;/4), and (3&#x3c0;/4), respectively, and for outputting information upon magnitudes and angles of the two vectors; a phase generator for generating eight phase signals corresponding to phases of (&#x2212;&#x3c0;/2), 0, (&#x3c0;/2), &#x3c0;, (&#x2212;3&#x3c0;/4), (&#x2212;&#x3c0;/4), (&#x3c0;/4), and (3&#x3c0;/4), respectively, and outputting the eight phase signals; and a selector for selecting two phase signals having phases equivalent to angles of the two vectors, from among the eight phase signals, and amplifying the two phase signals having been selected, based on the information upon the magnitudes and the angles, and outputting, as a plurality of amplification signals, the two phase signals having been amplified.

High efficiency transmitter

A transmission circuit that performs modulation based on a phase difference signal and an amplitude signal includes an asymmetrical phase rotation device. The asymmetrical phase rotation device performs an operation of subtracting 2&#x3c0; from a value of the phase difference signal when the value of the phase difference signal is greater than a predetermined positive threshold value, or an operation of adding 2&#x3c0; to the value of the phase difference signal when the value of the phase difference signal is less than a predetermined negative threshold value. Accordingly, the transmission circuit has distortion reduction characteristics improved uniformly over a range of frequencies higher or lower than a carrier wave band.

Transmission circuit and transmission method

A communications transmitter configured to reduce the average-to-minimum magnitude ratio (AMR) of a communications signal includes a symbol mapper, a pulse-shaping filter, an AMR reduction circuit, and a modulator. The symbol mapper operates to generate a sequence of symbols from a binary-source data stream containing a message to be transmitted, and the pulse-shaping filter generates a baseband signal based on the sequence of symbols. The AMR reduction circuit is configured to compare a magnitude of a local minimum of samples of the baseband signal to various magnitude threshold levels, and to modify the baseband signal in one of two manners depending on the relationship of the magnitude of the local minimum and the various threshold levels. Finally, the modulator operates to modulate a carrier signal based on the modulation information contained in the modified baseband signal.

Methods and apparatus for reducing the average-to-minimum magnitude ratio of communications signals in communications transmitters

A communications transmitter configured to reduce the average-to-minimum magnitude ratio (AMR) of a communications signal includes a symbol mapper, a pulse-shaping filter, an AMR reduction circuit, and a modulator. The symbol mapper operates to generate a sequence of symbols from a binary-source data stream containing a message to be transmitted, and the pulse-shaping filter generates a baseband signal based on the sequence of symbols. The AMR reduction circuit is configured to compare magnitudes of samples of the baseband signal to a time-varying low-magnitude threshold, and modify the baseband signal to produce a modified baseband signal having a reduced AMR if a sample of the baseband signal is determined to have a magnitude less than the time-varying low-magnitude threshold. Finally, the modulator operates to modulate a carrier signal based on the modulation information contained in the modified baseband signal.

Methods and apparatus for reducing the average-to-minimum power ratio (AMPR) of communications signals in communications transmitters. An AMPR-reducing method includes detecting a sample of a baseband signal having a magnitude less than a predetermined low-magnitude threshold. The magnitude and/or angle of the baseband signal is modified in the temporal vicinity of the detected low-magnitude sample, to form a modified baseband signal having a reduced AMPR. The baseband signal is modified by scaling an insertion pulse by a complex pulse insertion vector and combining the resulting scaled complex insertion pulse with the baseband signal in the temporal vicinity of the detected low-magnitude sample. The pulse insertion angle may be set to any angle within a pulse insertion vector range determined by a vector defining the detected low-magnitude sample and a vector that is orthogonal to the trajectory of the baseband signal.

Methods and apparatus for reducing the average-to-minimum power ratio of communications signals in communications transmitters

A nonlinear filter includes: a determination unit that determines, based on I and Q signals inputted into the determination unit, whether or not to perform pulse insertion; a rotation detector that detects a rotation direction of the I and Q signals on an IQ plane with respect to the origin of the IQ plane; a pulse generator that generates, when the determination unit determines to perform the pulse insertion, a pulse of which at least one of the direction and the magnitude is determined in accordance with at least the detected rotation direction; and an adder that inserts the pulse into the I and Q signals and outputs resultant I and Q signals.

Nonlinear filter and transmission circuit

A polar modulation transmitter includes an amplitude modulation (AM) path with an amplitude modulation to amplitude modulation (AM/AM') correction circuit and a phase modulation (PM) path with a delay element and an amplitude modulation to phase modulation (AM&#x2032;/PM) correction circuit. The AM/AM&#x2032; correction circuit receives and predistorts a digital amplitude component signal depending on amplitudes of samples in the digital amplitude component signal, thereby generating a predistorted digital amplitude component signal. The delay element receives and delays a digital phase component signal, to generate a delayed digital phase component signal having a delay corresponding to the latency introduced by the AM/AM&#x2032; correction circuit. The AM&#x2032;/PM correction circuit predistorts the delayed digital phase component signal depending on amplitudes of samples in the predistorted amplitude component signal, thereby generating a predistorted digital phase component signal.

Time alignment methods and apparatus for polar modulation transmitters

Methods and apparatus for controlling events, timing and operational characteristics of wireless communications devices. An exemplary wireless communications apparatus comprises a baseband processor, radio frequency (RF) generating circuitry, a programmable event controller, and a memory device. The RF generating circuitry and programmable event controller are integrated in the same integrated circuit. The memory device, which may also be embedded in the same integrated circuit as the event controller and RF generating circuitry, is configured to store a sequence of instructions the event controller executes in response to a baseband command. The memory device is also configured to store control parameter data, which the event controller retrieves and uses to enable, disable, select and deselect various devices on the integrated circuit and to set, adjust or modify the operational characteristics of the RF generating circuitry (e.g., band selection and tuning) and other circuitry (e.g., power control circuitry) of the communications apparatus.

Methods and apparatus for controlling the operation of wireless communications systems

Methods and apparatus for predistorting signals in a polar modulation transmitter. An exemplary method includes predistorting an envelope component signal in an amplitude path of a polar modulation transmitter according to a set of AM/AM predistortion coefficients, and predistorting a phase component signal in a phase path of the polar modulation transmitter according to a set of AM/PM predistortion coefficients. The AM/AM and AM/PM predistortion coefficients are stored in a memory in the form of a look up table (LUT). The envelope component signal is scaled and/or offset, before predistortion is applied, by an amount dependent upon which average power level of a plurality of average power levels the power amplifier of the polar modulation transmitter is configured to operate. Scaling and/or offsetting the envelope component signal prior to applying predistortion affords the ability to share the AM/AM and AM/PM predistortion coefficients of the predistortion LUT over the plurality of average power levels.

Predistortion methods and apparatus for polar modulation transmitters

Methods and apparatus for reducing the bandwidth of modulation signals in a phase path of a polar modulation transmitter. An exemplary method includes generating a phase difference modulation signal for a phase path of a polar modulation transmitter, and filtering the phase difference modulation signal using a linear-phase filter. Filtering the phase difference modulation signal may be performed by first detecting samples in the phase difference modulation signal that have phase difference values in excess of a phase difference threshold and then filtering samples in the vicinity of the threshold-violating samples to remove the threshold-violating events. Alternatively, all samples may be filtered, i.e., without regard as to whether any given sample exceeds a phase difference threshold, to remove large phase difference changes in the phase difference modulation signal, or a combination of linear-phase and nonlinear filters may be used to remove the large phase difference changes.

Methods and apparatus for reducing modulation signal bandwidth in polar modulation transmitters

The transmission apparatus and transmission power controlling method are able to keep high speed feedback control and control transmission power accurately. Polar modulation transmitter () is provided with LPF () that performs waveform shaping of output power of PA () and ADC () that obtains output power data for each mode by sampling filtered signals in compressed mode and filtered signals in uncompressed mode at the same phase as the filtered signals in compressed mode. In this way, the phases of sampling signals before and after the mode change are the same, so that it is possible to obtain sampling signals of the same condition before and after the mode change, from filtered signal waveforms. According to feedback control based on these sampling signals, even if drift components remain in the filtered signals, the influence can be ignored, so that it is possible to keep high speed feedback control, and estimate and control transmission power accurately.

Transmission apparatus and transmission power control method

A transmission apparatus has two modes of power amplifier operation, in which modeis inherently accurate, modeis inherently less accurate, and measurement of a power amplifier output from modeis used to correct a power amplifier output in mode. Modemay be a compressed mode and modemay be a non-compressed mode. The apparatus may include a power controller that provides overlapping scaling factor sets for modesandand controls transmission power using the scaling factor sets. Upon a mode transition, the controller uses the overlapping scaling factors and changes the scaling factor set for the mode of a destination of the transition based on actual measurement representative of transmission power, for example, by carrying out power alignment loop operations. A cellular mobile device may include such transmission apparatus. A polar modulation transmitter is also disclosed.

Transmission power controller

Methods and apparatus for reconstructing discrete-time amplitude modulation signals in polar modulation transmitters. An exemplary polar modulation transmitter includes a symbol generator, a rectangular-to-polar converter, a peak phase detector, and an amplitude modulation reconstruction circuit. The symbol generator generates rectangular-coordinate modulation symbols from which the rectangular-to-polar converter generates an amplitude modulation signal containing discrete-time amplitude samples and an angle modulation signal containing discrete-time angle samples. The peak phase detector circuit detects phase reversals or near phase reversals represented in samples of the angle modulation signal. The amplitude modulation reconstruction circuit responds by reconstructing samples in the amplitude modulation signal that correspond to detected phase reversals or a near phase reversals represented in samples of the angle modulation signal.

Methods and apparatus for reconstructing amplitude modulation signals in polar modulation transmitters

A frequency modulator capable of performing frequency modulation without increasing quantization noise; and a method for adjusting the gain thereof are provided. An input signal is gain-adjusted by a gain adjustment section and outputted to a frequency modulation section. The frequency modulation section is gain-controlled based on a first signal. For setting a digital gain coefficient and an analog gain coefficient of the gain adjustment section, a test signal is inputted. In this state, in a generation section, first control information for setting the digital gain coefficient and second control information for setting the analog gain coefficient are generated based on information regarding a state of the frequency modulation section.

Frequency modulator and method for adjusting gain thereof

Even when there is limit placed upon transmission power control time, the transmission power control method enables accurate control transmission power. The transmission power control method includes: a first measuring step of measuring, in a symbol interval before a symbol interval where mode of the power amplifier changes, output power of the power amplifier before mode changes; a first setting step of setting target power of the power amplifier after mode changes based on a measurement result obtained in the first measuring step and a transmission power control signal; a second measuring step of measuring, in the symbol interval where mode of the power amplifier changes, output power of the power amplifier after mode changes, the output power being controlled using the target power set in the first setting step; and a second step of setting corrected target power based on a measurement result obtained in the second measuring step.

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San Mateo, CA, United States of America

Wayne S Lee