Abstract: 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.

Abstract: 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).

Abstract: 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.

Abstract: 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.

Abstract: 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.

Abstract: A voltage controlled oscillator of the present invention comprises a reference voltage generation section 114 for generating a plurality of reference voltage based on a power supply voltage. A first to a third reference voltages Vref1, Vref2, and Vref3 are inputted to a first to a third variable capacitance circuits A, B, and C, respectively, at each one of terminals of each of the first to the third variable capacitance circuits A, B, and C. The first to the third reference voltages Vref1, Vref2, and Vref3 each has a fixed value, and a difference between the first reference voltage Vref1 and the second reference voltage Vref2 and a difference between the second reference voltage Vref2 and the third reference voltage Vref3 represent values different from each other.

Abstract: A voltage-controlled oscillator having an inductor circuit, n pieces (n is two or more) of variable capacitance circuit having variable capacitance elements, negative resistance circuits, and reference voltage generation means of generating a reference voltage from a power supply voltage, and wherein a predetermined reference voltage is inputted to some terminals of the variable capacitance elements of the n pieces of variable capacitance circuit, a control voltage is inputted to the other terminals thereof, and of the variable capacitance elements of the n pieces of variable capacitance circuits, the predetermined reference voltage inputted to some terminals of the variable capacitance elements of at least two pieces of the variable capacitance circuit is different.

Abstract: The present invention provides a differential voltage control oscillator including: a parallel resonance circuit in which an inductor circuit, a variable capacitance circuit, and a radio-frequency switching circuit are connected in parallel together; and a negative resistance circuit connected in parallel with the parallel resonance circuit.

Abstract: A voltage controlled oscillator comprises a parallel resonance circuit including an inductor circuit, a variable capacitance circuit, and a high-frequency switch circuit, a negative resistance circuit and a frequency control section, and a frequency tuning sensitivity control section. The frequency control section shifts a band of an oscillation frequency by controlling ON/OFF of a switching element included in the high-frequency switch circuit. The frequency tuning sensitivity control section adjusts a change rate of a total capacitance of the variable capacitance circuit with respect to a control voltage, depending on a band to be used. The frequency tuning sensitivity control section is connected to a virtual ground point of a differential signal.

Abstract: In a signal generating circuit SG1, a 90 -degree divider 3 generates, from a local oscillation signal SLO supplied through an input terminal 1, an intermediate reference phase signal ISREF and an intermediate quadrature signal ISQR orthogonal in phase to the intermediate reference phase signal ISREF for output to mixers 6 and 7, respectively. A shifter 4 shifts the phase of the local oscillation signal supplied through an input terminal 2 by a predetermined amount to generate a shift signal SSFT for output through a divider 5 to the mixers 6 and 7. The mixer 6 mixes the input intermediate reference phase signal ISREF and the input shift signal SSFT to generate a reference phase signal SREF. The mixer 7 mixes intermediate quadrature signal ISQR and the input shift signal SSFT to generate a quadrature signal SQR. With this, it is possible to provide a signal generator capable of generating highly-accurate, high-frequency reference phase signals and quadrature signals.

Abstract: A voltage controlled oscillator comprises a parallel resonance circuit including an inductor circuit, a variable capacitance circuit, and a high-frequency switch circuit, a negative resistance circuit and a frequency control section, and a frequency tuning sensitivity control section. The frequency control section shifts a band of an oscillation frequency by controlling ON/OFF of a switching element included in the high-frequency switch circuit. The frequency tuning sensitivity control section adjusts a change rate of a total capacitance of the variable capacitance circuit with respect to a control voltage, depending on a band to be used. The frequency tuning sensitivity control section is connected to a virtual ground point of a differential signal.

Abstract: The present invention provides a differential voltage control oscillator including: a parallel resonance circuit in which an inductor circuit, a variable capacitance circuit, and a radio-frequency switching circuit are connected in parallel together; and a negative resistance circuit connected in parallel with the parallel resonance circuit.

Abstract: A voltage-controlled oscillator having an inductor circuit, n pieces (n is two or more) of variable capacitance circuit having variable capacitance elements, negative resistance circuits, and reference voltage generation means of generating a reference voltage from a power supply voltage, and wherein a predetermined reference voltage is inputted to some terminals of the variable capacitance elements of the n pieces of variable capacitance circuit, a control voltage is inputted to the other terminals thereof, and of the variable capacitance elements of the n pieces of variable capacitance circuits, the predetermined reference voltage inputted to some terminals of the variable capacitance elements of at least two pieces of the variable capacitance circuit is different.

Abstract: The present invention provides an oscillator or PLL circuit which can balance the characteristics of a circuit without being affected by noise from a signal line or a supply line. There is provides an oscillator comprising a resonance circuit has a first series connected circuit having coils and a power terminal, a second series connected circuit having capacitors and a varactor having directional characteristics, and a third series connected circuit having capacitors and a varactor having directional characteristics. The first, second, and third series connected circuits are connected in parallel. The varactors are connected so as to have opposite directionalities with respect to a connection side of the second and third series connected circuit. The capacities of the varactors are varied by external control. The varied capacities determine an oscillation frequency.

Abstract: The present invention provides a voltage controlled oscillator for changing an oscillating frequency in accordance an input control voltage, including a parallel resonant circuit, a negative resistance circuit connected in parallel to the parallel resonant circuit, a first capacitor connected in parallel to the negative resistance circuit, a first current source connected between one terminal of the first capacitor and the negative resistance circuit, and a second current source connected between the other terminal of the first capacitor and the negative resistance circuit. The capacitance value of the first capacitor is set to a value that suppresses a signal with a frequency twice the oscillating frequency at both the terminals of the first capacitor. Each of the first and the second current sources is constituted by a bipolar transistor.

Abstract: To provide a printed circuit board, a buildup substrate and a method of manufacturing the printed circuit board capable of curbing a transmission loss thereof at a desired frequency.

Abstract: The present invention provides an oscillator or PLL circuit which can balance the characteristics of a circuit without being affected by noise from a signal line or a supply line. The present invention provides an oscillator comprising a resonance circuit has a first series connected circuit having coils and a power terminal, a second series connected circuit having capacitors and a varactor having directional characteristics, and a third series connected circuit having capacitors and a varactor having directional characteristics. The first, second, and third series connected circuits are connected in parallel. The varactors are connected so as to have opposite directionalities with respect to a connection side of the second and third series connected circuit. The capacities of the varactors are varied by external control. The varied capacities determine an oscillation frequency.

Abstract: In a signal generating circuit SG1, a 90-degree divider 3 generates, from a local oscillation signal SLO supplied through an input terminal 1, an intermediate reference phase signal ISREF and an intermediate quadrature signal ISQR orthogonal in phase to the intermediate reference phase signal ISREF for output to mixers 6 and 7, respectively. A shifter 4 shifts the phase of the local oscillation signal supplied through an input terminal 2 by a predetermined amount to generate a shift signal SSFT for output through a divider 5 to the mixers 6 and 7. The mixer 6 mixes the input intermediate reference phase signal ISREF and the input shift signal SSFT to generate a reference phase signal SREF. The mixer 7 mixes intermediate quadrature signal ISQR and the input shift signal SSFT to generate a quadrature signal SQR. With this, it is possible to provide a signal generator capable of generating highly-accurate, high-frequency reference phase signals and quadrature signals.

Abstract: A method for generating a local oscillation signal comprising two separate frequency converters, of which one frequency converter includes an output unit for generating an internal output signal to be used for its frequency conversion, and the other frequency converter employs the same internal output signal from the output unit as the local oscillation signal.