Patent application number | Description | Published |
20080204157 | VOLTAGE CONTROLLED OSCILLATOR, AND PLL CIRCUIT AND RADIO COMMUNICATION APPARATUS USING THE SAME - A voltage controlled oscillator of the present invention comprises a reference voltage generation section | 08-28-2008 |
20090176464 | Multiple-mode modulator to process baseband signals - A multiple-mode modulator is configured similarly to a direct conversion quadrature modulator with an infusion of an amplitude modulation signal path from a large signal polar modulator to improve the power amplifier efficiency. The multiple-mode modulator also includes a radio frequency signal path. The multiple-mode modulator is configured to receive a baseband signal, convert the baseband signal to a radio frequency (RF) signal, and to process the RF signal according to either a polar mode or a quadrature mode, depending on a time-varying input voltage of the RF signal. When the power amplifier operates in the linear region, the RF signal is processed according to the quadrature mode. When the power amplifier operates in the compressed region, the RF signal is processed according to the polar mode. The multiple-mode modulator can be configured according to a small signal polar architecture or a large signal polar architecture, having either an open-loop or closed-loop configuration. | 07-09-2009 |
20090191826 | High-Efficiency Envelope Tracking Systems and Methods for Radio Frequency Power Amplifiers - Envelope tracking (ET) methods and systems for controlling the delivery of power to radio frequency power amplifiers (RFPAs). An exemplary ET system includes an RFPA and a wide bandwidth capable and power efficient envelope modulator that includes a first power supplying apparatus and a second power supplying apparatus. The first power supplying apparatus includes a switch-mode converter and a regulator. The first mode converter is operable to dynamically step down a fixed power supply voltage according to amplitude variations in an envelope signal received by the regulator, and use the resulting dynamic power supply signal to power the regulator. The second power supplying apparatus is connected in parallel with the first power supplying apparatus. Depending on a power of an output signal to be generated at an output of the power amplifier, power is supplied to the power amplifier from either or both of the first and second power supplying apparatuses. | 07-30-2009 |
20090289720 | High-Efficiency Envelope Tracking Systems and Methods for Radio Frequency Power Amplifiers - High-efficiency envelope tracking (ET) methods and apparatus for dynamically controlling power supplied to radio frequency power amplifiers (RFPAs). An exemplary ET circuit includes a switch-mode converter coupled in parallel with a split-path linear regulator. The switch-mode converter is configured to generally track an input envelope signal Venv and supply the current needs of a load (e.g., an RFPA). The split-path linear regulator compensates for inaccurate envelope tracking by sourcing or sinking current to the load via a main current path. A current sense path connected in parallel with the main current path includes a current sense resistor used by a hysteresis comparator to control the switching of the switch-mode converter. The split-path linear regulator is configured so that current flowing in the current sense path is a lower, scaled version of the current flowing in the main current path. | 11-26-2009 |
20100015932 | SIGNAL DECOMPOSITION METHODS AND APPARATUS FOR MULTI-MODE TRANSMITTERS - A multi-mode communications transmitter includes a signal decomposer that converts rectangular-coordinate in-channel and quadrature channel signals into polar-coordinate amplitude and angle component signals and form therefrom first and second modulation signals. The signal decomposition process performed by the signal decomposer combines envelope-reduction and restoration (ERR) with filtering to reduce the bandwidths of the first and second modulation signals compared to the bandwidths of the unmodified amplitude and angle component signals. The reduction in signal bandwidths eases the design requirements of the electrical components needed to process and generate the signals applied to the power supply and radio frequency (RF) input ports of the multi-mode communications transmitter's power amplifier (PA). It also makes the multi-mode communications transmitter more forgiving to gain and delay mismatches between the signals applied to the power supply and RF input ports of the PA, compared to conventional polar modulation transmitters. | 01-21-2010 |
20100056068 | MULTI-MODE TRANSMITTER HAVING ADAPTIVE OPERATING MODE CONTROL - Methods and apparatus for transmitting communications signals that are both power efficient and effective at avoiding or reducing transmitter-generated receive band noise. An exemplary transceiver apparatus includes a multi-mode transmitter that is configurable to operate in a plurality of operating modes (e.g., a polar mode, a quadrature mode and a hybrid mode), a receiver, and an operating mode controller. The operating mode controller is configured to control which operating mode the transmitter is to operate, depending on one or more of a transmit (Tx) power, receive (Rx) power, the Tx power relative to the Rx power, a level of frequency separation between a Tx frequency band and a Rx frequency band (Tx/Rx band separation), and modulation type employed by the transmitter. | 03-04-2010 |
20100069025 | HIGH-EFFICIENCY TRANSMITTER WITH LOAD IMPEDANCE CONTROL - A transmitter generates first and second constant-envelope radio frequency (RF) component signals having first and second phase angles. The first and second phases are controlled by a phase controller. First and second nonlinear power amplifiers (PAs) are modulated by an amplitude-modulated power supply signal as the first and second constant-envelope RF component signals are amplified. The phase controller controls the first and second phases of the first and second constant-envelope RF component signals, in response to a power control signal, and, in so doing, controls an effective load impedance seen at the outputs of the first and second nonlinear PAs. By controlling the effective load impedance in response to a power control signal, rather than in response to rapid amplitude variations in an input signal envelope, the output power of the transmitter is efficiently controlled over a wide dynamic range even at low output powers. | 03-18-2010 |
20100117744 | PHASE ERROR CORRECTION IN ROTARY TRAVELING WAVE OSCILLATORS - An RTWO apparatus includes an N-phase RTWO (N is an integer greater than or equal to two) and a phase correction circuit. The N-phase RTWO includes a closed-loop transmission line formed as a Moebius strip. The closed-loop transmission line includes N transmission line segments, to which N voltage controlled capacitors are coupled. The N transmission line segments provide N output phases. The phase correction circuit operates to detect phase errors between output phases, and, depending on the detected phase errors, generates N control voltages for controlling the capacitances of the N voltage controlled capacitors. Controlling the capacitances of the N voltage controlled capacitors in this coordinated manner reduces the phase errors among the N output phases, thereby providing a phase accurate multi-phase RTWO output. | 05-13-2010 |
20100123523 | STANDING WAVE OSCILLATORS - A standing wave oscillator (SWO) is formed from a microstrip transmission line or a stripline transmission line having a closed-loop single signal trace. Using the microstrip transmission line or stripline transmission line, the SWO can be formed with bends and in complex shapes, which are not so easily realized or possible using coplanar stripline (CPS) transmission lines. Simulation results demonstrate that the microstrip and stripline transmission line based SWOs provide superior operational characteristics (e.g., higher quality factors (Qs)) compared to a CPS transmission line based SWO of similar size and geometry. | 05-20-2010 |
20100301953 | PHASE LOCK LOOP WITH A MULTIPHASE OSCILLATOR - A phase lock loop utilizes a multiphase oscillator having a plurality of digital inputs. A plurality of DQ flip-flops, offset in time from each other generate a plurality of control signals to remove control phase information from the oscillator in digital form. A DQ flip-flop connected between any two digital inputs on the oscillator determines direction of the traveling wave. The direction and phase information address a look-up table to determine the current fractional phase of the oscillator. A divide by N circuit is used to reduce the oscillator frequency. A total phase indicator signal for the oscillator is determined using the current fractional phase. The total phase is compared to a reference phase to produce a control signal for making adjustments to the oscillator. In a feed-forward path, frequency dividers divide a high frequency signal from the oscillator to a lower desired frequency, thereby increasing phase resolution. | 12-02-2010 |
20100303135 | METHOD AND APPARATUS FOR DIRECT RF TO DIGITAL CONVERTER - The invention relates to a method and apparatus for decomposing a high frequency incoming signal into several low frequency signals without the loss of any information. The low frequency signals can define a plurality of digital data streams. The decomposing steps are implemented without processing the signal through a mixer or a local oscillator and without degrading the SNR. In a preferred embodiment, a decomposing circuit includes a single-to-differential converter for decomposing the incoming high frequency signal into a first and a second signal having opposite polarity. Each of the first and the second incoming signals is then processed through multistage cascading logic units which reduce the frequency of the respective signals to provide a plurality of low-frequency data streams. The resulting slow-speed data streams are combined to form a low-speed data stream containing all the information provided by the original high-frequency signal. | 12-02-2010 |
20110018640 | TRANSMITTER UTILIZING A DUTY CYCLE ENVELOPE REDUCTION AND RESTORATION MODULATOR - A broad power band transmitter utilizing a duty cycle modulator achieves 80dB of power range for 3G signals. The present invention greatly improves the efficiency of transmitters used in mobile phones, for example, by using the duty cycle modulator during medium and low power levels of the transmitting power amplifier. The power amplifier operates in three different modes based upon the amplifier power level selected. The power amplifier operates in an EER mode during high power levels, in a DCM ERR mode during medium power levels, and in a DCM mode during low power levels. | 01-27-2011 |
20110176636 | HIGH-EFFICIENCY ALL-DIGITAL TRANSMITTER - A low cost high-efficiency all-digital transmitter using all-digital power amplifiers (“DPA”) and various mapping techniques to generate an output signal, which substantially reproduces a baseband signal at a carrier frequency. A baseband signal generator generates a baseband signal which is quantized by a signal processor using a quantization map. A DPA control mapper outputs control signals to phase selectors using the quantized signal and a quantization table. Each phase selector receives one of the control signals and outputs a waveform at a carrier frequency with a phase corresponding to the control signals, or an inactive signal. Each DPA in a DPA array has an assigned weight, receives one of the waveforms from the phase selectors, and outputs a power signal according to the weight of the DPA and the phase of the received waveform. The combined power signal substantially reproduces the baseband signal at the carrier frequency. | 07-21-2011 |