349 results about "Constant envelope" patented technology

Multiple radio channel frequency signals that are modulated with respective information modulation are transmitted from a common antenna at multiple radio frequencies. Multiple modulators are provided, a respective one of which corresponds to a respective one of the radio channel frequencies. Each modulator generates at least one constant amplitude, phase modulated drive signal at the corresponding radio channel frequency from the respective information modulation, such that the at least one constant amplitude, phase modulated drive signal corresponds to the information modulation for the corresponding radio frequency. At least one saturated power amplifier is provided for each of the at least one constant amplitude, phase modulated drive signals. A respective saturated power amplifier is responsive to the corresponding constant amplitude, phase modulated drive signal, to produce a corresponding amplified output signal at an output thereof. A coupling network connects the outputs of the saturated power amplifiers in series, to produce a combined signal that is applied to the common antenna, such that the common antenna radiates the radio channel frequency signals that are modulated with the respective information modulation. In first embodiments, the at least one constant amplitude, phase modulated drive signal is a single constant envelope modulation drive signal, wherein the information modulation is a constant envelope information modulation. In other embodiments, at least two constant amplitude phase modulated drive signals are provided at the corresponding radio channel frequency, such that the at least two constant amplitude, phase modulated drive signals correspond to the information modulation for the corresponding radio frequency.

Binary and Quadrature Feher's Modulation (F-Modulation, or FMOD) Transmitter-Receiver systems and circuits exhibit reduced envelope fluctuation and peak radiation, and increased efficiency. A subclass of these systems has a constant envelope. They advantageously provide lower power operation with improved performance including robust BER performance, and compatibility with both linearly and nonlinearly amplified narrow spectrum, and without disadvantages of conventional BPSK, DBPSK QPSK and pi/4-QPSK. Feher's BPSK (FBPSK) is an improved efficiency transmitter which is compatible with conventional BPSK receivers. FBPSK modems are based on using quadrature structure where Q-channel data is inserted in quadrature with I-channel data for certain applications. The Q-channel data may be “offset” from the I-channel data by an amount selectable between zero and a specified time. Further improvement in the spectrum is attained using correlation between I and Q channels. FBPSK modem is shown to meet the IEEE 802.11 specified spectral direct sequence spread spectrum mask (−30 dB point) for wireless LAN, and leads to an output power gain of 6.5 dB over conventional BPSK modems. The cross-coupled quadrature FMOD structure is also suitable for continuous mode and for burst operated TDMA, FDMA, CDMA, WCDMA and CSMA Frequency Modulation Quadrature AM (QAM), QPSK and offset QPSK, as well as pi/4-shifted QPSK modems/processors. Reduced modulation index Gaussian FSK (GFSK), multilevel FM and cross-coupled Quadrature Amplitude Modulated (QAM) transmitters and combinations of these modulations and corresponding coherent demodulators are disclosed. Controlled rise and fall time descriptions of burst operated systems are included.

Methods and systems for vector combining power amplification are disclosed herein. In one embodiment, a plurality of signals are individually amplified, then summed to form a desired time-varying complex envelope signal. Phase and/or frequency characteristics of one or more of the signals are controlled to provide the desired phase, frequency, and/or amplitude characteristics of the desired time-varying complex envelope signal. In another embodiment, a time-varying complex envelope signal is decomposed into a plurality of constant envelope constituent signals. The constituent signals are amplified equally or substantially equally, and then summed to construct an amplified version of the original time-varying envelope signal. Embodiments also perform frequency up-conversion.

A signal processor has an input terminal and an output terminal for use in a wireless transmitter, for generating a radio frequency signal suitable for transmission, either with or without further power amplification. The signal processor separates an input signal into first and second processing paths, the first processing path generating a pulse train signal which is a digitised envelope signal, and the second processing path comprising phase processing means operable to generate a constant envelope phase signal. An RF switch is operable to switch the phase signal by means of the pulse train signal.

The invention relates to a transmitter which comprises a modulator providing a phase-modulated constant-envelope radio-frequency signal, and to a method of controlling the power level of a signal output by such a transmitter. In order to enable a power control over a large power range, it is proposed that a provided phase-modulated constant-envelope radio-frequency signal is divided into two identical signals for the power control. A first control arrangement then controls the output power for higher power levels by controlling amplifications applied to the two signals. A second control arrangement controls the output power for lower power levels by controlling phase shifts applied to the two signals. The processed signals are then combined and provided as a power controlled output signal.

A Switch Node Assisted Linear architecture, including a linear amplifier in parallel with a switched converter, is configurable in two tracking modes: (a) a SMAL regulator in which the amplifier sets toad voltage with an envelope tracking bandwidth, and the switched converter is configured for current assist, and (b) a Switched Mode Power Supply configuration in which the amplifier is switch-decoupled, and the switcher circuit is switched configured with an output capacitor, operable as an SMPS providing load voltage with an adaptive tracking bandwidth that is less than the envelope tracking bandwidth. Staged switching effects substantially seamless transitions between tracking modes, with the amplifier holding the load voltage at a substantially constant envelope tracking voltage (CVET): (a) for ET-AT transitions, the CVET mode enables pre-charging the output capacitor to a target AT voltage, prior to switch-decoupling the amplifier; and (b) for AT-ET transitions, CVET mode enables discharging the output capacitor.

A multilevel LINC transmitter. The multilevel LINC transmitter comprises a multilevel signal component separator, a phase modulator block, and an RF block. The multilevel signal component separator comprises a multilevel scaler and converts a base band signal to constant envelope signals. The phase modulator block is coupled to the multilevel signal component separator. The RF block comprises a plurality of power amplifiers coupled to the phase modulator block and the multilevel scaler and a power combiner coupled to the power amplifiers.

A method for generating a global positioning signal from a space based craft including the steps of generating a plurality of binary modulating signals using a waveform generator; separately modulating an in-phase component of a desired carrier of the global positioning signal to be generated with at least a first binary, modulating signal selected from the plurality to generate at least one corresponding in-phase modulated signal component; separately modulating a quadrature component of the carrier with at least a second binary modulating signal selected from the plurality to generate at least one corresponding quadrature modulated signal component; and, combining the at least one in-phase modulated signal component and the at least one quadrature modulated signal component to generate the global positioning signal; wherein the global positioning signal has a constant envelope.

A multi-mode radio transmitter for use in mobile radio cellular standards, such as 2G, 2.5G and 3G, and a method of operating the transmitter in which an input signal is modulated independently of controlling the drive of a power amplifier (PA) module (40). The transmitter comprises circuitry (12, 60) for extracting the phase (θ) and amplitude (R) components from envelope information in the input signal. A modulator (110) uses the phase component (θ) to produce a constant-envelope signal comprising a phase modulated real signal at the transmitter frequency. This signal is multiplied in a multiplier (72) with either a fixed bias voltage (V_g1) to produce a constant envelope signal or a low level envelope tracking signal derived from an amplitude component (R) by a first amplitude control circuit (78) to produce a signal modulated exactly by the amplitude component. An output from the multiplier is applied to the PA module (40) having a control input (41). The PA module is controllable in a plurality of manners dependent on the characteristics and the required output power of the signal being transmitted. These manners include applying a predetermined fixed voltage to the control input or a less precise envelope tracking signal which is derived by a second amplitude control circuit (120) from the amplitude component (R).

A method (200) and circuit (100) for substantially maintaining an amplified constant envelope modulation signal at a constant pre-defined amplitude. The circuit (100) comprises a constant envelope modulation providing circuitry (104), a power amplifier (102), a power amplifier driver (106), a coupler (108) and a feedback circuit (110). In operation the sensor (110) has an output (120) that provides a radio frequency output signal proportional to an amplitude of an amplified constant envelope modulated radio frequency signal provided to the amplifier input (118) from the power amplifier driver (106). The feedback circuit (110) provides a gain control voltage a driver gain control input to maintain the constant envelope modulation signal at a constant pre-defined amplitude supplied to the amplifier input (118).

In a modulation system, in order to provide a two-level signal with a desired modulation which is suited to be amplified by a switching mode power amplifier, the modulation system may include a first constant envelope modulator modulating a signal according to a first control signal, a second constant envelope modulator modulating a signal according to a second control signal, and a combining portion combining the output signal of the first and said second constant envelope modulator to a single, two-level pulse-width-modulated signal. The information which is to be represented by the modulation of the single, two-level pulse-width-modulated signal is coded in the first and the second control signals. The invention relates equally to a corresponding method for generating a modulated signal.

The present invention provides an amplifier for a wireless transmitter. In one embodiment, the amplifier includes a signal separator for decomposing an input signal into constant envelope signals and amplifier circuits for amplifying the constant envelope signals. The amplifier also includes a combiner for combining the amplified constant envelope signals to form an output signal that is an amplified representation of the input signal. Linear correction circuits are used to apply gain, phase, and/or delay correction to the constant envelope signals. The corrections are determined based upon a feedback portion of the output signal. Pre-distortion circuits are used to apply a non-linear pre-distortion to the constant envelope signals. The non-linear pre-distortion is determined based upon the feedback portion of the output signal.

An RF transmitter provides both GSM and EDGE capability by implementing collector voltage control over the power transistor(s) in a power amplifier. During EDGE mode, linear base-biasing a power amplifier (PA) allows collector control to provide either saturated mode PA operation (during ramp up/ramp down) or linear mode PA operation (during data burst). Collector control can therefore be used to provide the accurate ramp up and ramp down profiles required for both GSM and EDGE burst output signals, and can also be used to set the level of the constant envelope data burst of a GSM burst output signal, while linear mode PA operation can provide the non-constant envelope EDGE data burst. A variable gain amplifier is used to adjust the input signal to the power amplifier such that the desired transmission level is achieved.

A power amplifier (1) for receiving and amplifying an input signal (10) and outputting an output signal (11) is disclosed. The power amplifier comprises: N power amplifying units (12) (N is an integer larger than 1) connected in parallel so as to output amplified signals in response to the input signal (10); an output combining unit (14) for combining the output signals from the N power amplifying units (12) and outputting a combined signal as the output signal (11) of the power amplifier; and an amplitude controlling unit (15) for selectively turning ON each of the N power amplifying units (12) based on an amplitude of the input signal (10). In the power amplifier, the amplitude controlling unit (15) may comprise N amplitude adjusters (113) connected in parallel for adjusting the amplitude of the input signal (110) of the power amplifier; and a controller (115) for selectively turning ON each of the N power amplifying units (112) and controlling the amplitude adjusters (113) so that an amplitude of the output signal (111) becomes a substantially continuous function with respect to the amplitude of the input signal (110). The power amplifier may further comprise a local oscillator (222) outputting an constant envelope signal, receiving a modulation signal (210) as the input signal of the power amplifier and outputting an amplified modulated signal (211) as the output signal of the power amplifier; wherein the N power amplifying units comprise N saturation amplifying units connected in parallel so as to amplify the constant envelope signal from the local oscillator; and the amplitude controlling unit comprises an amplifying controller (215) for selectively turning ON each of the N saturation amplifying units (212) based on an amplitude of the modulation signal (210).

Methods and systems for vector combining power amplification are disclosed herein. In one embodiment, a plurality of signals are individually amplified, then summed to form a desired time-varying complex envelope signal. Phase and/or frequency characteristics of one or more of the signals are controlled to provide the desired phase, frequency, and/or amplitude characteristics of the desired time-varying complex envelope signal. In another embodiment, a time-varying complex envelope signal is decomposed into a plurality of constant envelope constituent signals. The constituent signals are amplified equally or substantially equally, and then summed to construct an amplified version of the original time-varying envelope signal. Embodiments also perform frequency up-conversion.

Methods and systems for vector combining power amplification are disclosed herein. In one embodiment, a plurality of signals are individually amplified, then summed to form a desired time-varying complex envelope signal. Phase and/or frequency characteristics of one or more of the signals are controlled to provide the desired phase, frequency, and/or amplitude characteristics of the desired time-varying complex envelope signal. In another embodiment, a time-varying complex envelope signal is decomposed into a plurality of constant envelope constituent signals. The constituent signals are amplified equally or substantially equally, and then summed to construct an amplified version of the original time-varying envelope signal. Embodiments also perform frequency up-conversion.

Methods and systems for vector combining power amplification are disclosed herein. In one embodiment, a plurality of signals are individually amplified, then summed to form a desired time-varying complex envelope signal. Phase and/or frequency characteristics of one or more of the signals are controlled to provide the desired phase, frequency, and/or amplitude characteristics of the desired time-varying complex envelope signal. In another embodiment, a time-varying complex envelope signal is decomposed into a plurality of constant envelope constituent signals. The constituent signals are amplified equally or substantially equally, and then summed to construct an amplified version of the original time-varying envelope signal. Embodiments also perform frequency up-conversion.