Abstract: Circuits, devices and methods are disclosed, including a phase shifter configured to provide a bypass state, a single first-handed quarter-wave state, a double first-handed quarter-wave state, or a single second-handed quarter-wave state utilizing two or less inductors. In some implementations, a phase shifter is disclosed to provide a first node and a second node, a first switchable path having a first inductance and a second inductance arranged in series between the first and second nodes, a capacitive grounding path implemented on each side of each of the first and second inductances, at least one of the capacitive grounding paths configured as a switchable capacitive grounding path, and a reconfiguring circuit assembly configured to allow the phase shifter to provide a plurality of quadrant phase shifts utilizing the first and second inductances and the at least one switchable capacitive grounding path.

Abstract: Disclosed are circuits and method for reducing or eliminating reference spurs in frequency synthesizers. In some implementations, a phase-locked loop (PLL) such as a Frac-N PLL of a frequency synthesizer can include a phase frequency detector (PFD) configured to receive a reference signal and a feedback signal. The PFD can be configured to generate a first signal representative of a phase difference between the reference signal and the feedback signal. The PLL can further include a compensation circuit configured to generate a compensation signal based on the first signal. The PLL can further includes a voltage-controlled oscillator (VCO) configured to generate an output signal based on the compensation signal. The compensation signal can include at least one feature for substantially eliminating one or more reference spurs associated with the PLL.

Abstract: Circuits, devices and methods are disclosed, including radio-frequency circuitry comprising a polar modulator configured to invert a sampled transmitted signal into an inverted sampled transmitted signal, a signal combiner configured to combine the inverted sampled transmitted signal with a received signal and a control logic circuit coupled to the polar modulator, the control logic circuit configured to adjust one or more tuning parameters of the polar modulator for inverting the sampled transmitted signal.

Abstract: A variable capacitor is disclosed, having a variable capacitance between a first node and a second node. The variable capacitor comprises a switch having a first terminal and a second terminal, the impedance between the first terminal and the second terminal being controllable via a control node. The variable capacitor further includes a first capacitor coupled between the first terminal and the first node, and a second capacitor coupled between the second terminal and the second node.

Abstract: A radio-frequency (RF) module includes a first transistor having a base, a collector, and an emitter, a radio-frequency output transmit path coupled to the collector of the first transistor at a first end and to a radio-frequency output port at a second end, and an output matching network disposed in the radio-frequency output transmit path, the output matching network including a shunt arm coupled to ground, the shunt arm including a switch that is controllable to modify an impedance of the output matching network.

Abstract: A radio-frequency (RF) module includes a driver transistor having a base, collector and emitter, an RF input port coupled to the base of the driver transistor, a cascode transistor having a base, collector and emitter, the emitter of the cascode transistor being coupled to the collector of the driver transistor, an RF output port coupled to the collector of the cascode transistor, and a coupling path connecting the base of the cascode transistor to the emitter of the cascode transistor, the coupling path including a capacitor.

Abstract: A radio-frequency module comprises a low-noise amplifier including a common source transistor having a gate node that receives a radio-frequency input signal and a drain node that transmits a combined radio-frequency output signal, and a correction signal input path configured to receive a correction signal and provide the correction signal to a source node of the common source transistor to generate, at least in part, the combined radio-frequency output signal.

Abstract: Circuits, devices and methods are disclosed, including a phase shifter configured to provide a bypass state, a single first-handed quarter-wave state, a double first-handed quarter-wave state, or a single second-handed quarter-wave state utilizing two or less inductors. In some implementations, a phase shifter is disclosed to provide a first node and a second node, a first switchable path having a first inductance and a second inductance arranged in series between the first and second nodes, a capacitive grounding path implemented on each side of each of the first and second inductances, at least one of the capacitive grounding paths configured as a switchable capacitive grounding path, and a reconfiguring circuit assembly configured to allow the phase shifter to provide a plurality of quadrant phase shifts utilizing the first and second inductances and the at least one switchable capacitive grounding path.

Abstract: Circuits, devices and methods are disclosed, including a phase shifter comprising a first node and a second node, and a first transmission line element having an inductance and a variable capacitance on each side of the inductance, the variable capacitance configured to provide a plurality of capacitance values to yield corresponding phase shift values based on an increment having a magnitude that is less than 90 degrees. In some implementations, the phase shifter further comprises a second transmission line element in series with the first transmission line element, the second transmission line element having an inductance and a variable capacitance on each side of the inductance configured to extend an overall phase shift range provided by the phase shifter.

Abstract: Disclosed are systems and method for controlling frequency synthesizers. A control system can be implemented in a phase-locked loop (PLL), such as a Frac-N PLL of a frequency synthesizer, to reduce or eliminate reference spurs. In some embodiments, such a control system can include a phase detector configured to receive a reference signal and a feedback signal. The phase detector can be configured to generate a first signal representative of a phase difference between the reference signal and the feedback signal. The control system can further include a charge pump configured to generate a compensation signal based on the first signal. The control system can further includes an oscillator configured to generate an output signal based on the compensation signal. The compensation signal can be configured to reduce or substantially eliminate one or more reference spurs associated with the frequency synthesizer.

Abstract: Disclosed are circuits and method for reducing or eliminating reference spurs in frequency synthesizers. In some implementations, a phase-locked loop (PLL) such as a Frac-N PLL of a frequency synthesizer can include a phase frequency detector (PFD) configured to receive a reference signal and a feedback signal. The PFD can be configured to generate a first signal representative of a phase difference between the reference signal and the feedback signal. The PLL can further include a compensation circuit configured to generate a compensation signal based on the first signal. The PLL can further includes a voltage-controlled oscillator (VCO) configured to generate an output signal based on the compensation signal. The compensation signal can include at least one feature for substantially eliminating one or more reference spurs associated with the PLL.

Abstract: Disclosed are circuits and method for reducing or eliminating reference spurs in frequency synthesizers. In some implementations, a phase-locked loop (PLL) such as a Frac-N PLL of a frequency synthesizer can include a phase frequency detector (PFD) configured to receive a reference signal and a feedback signal. The PFD can be configured to generate a first signal representative of a phase difference between the reference signal and the feedback signal. The PLL can further include a compensation circuit configured to generate a compensation signal based on the first signal. The PLL can further includes a voltage-controlled oscillator (VCO) configured to generate an output signal based on the compensation signal. The compensation signal can include at least one feature for substantially eliminating one or more reference spurs associated with the PLL.

Abstract: Disclosed are systems and method for controlling frequency synthesizers. A control system can be implemented in a phase-locked loop (PLL), such as a Frac-N PLL of a frequency synthesizer, to reduce or eliminate reference spurs. In some embodiments, such a control system can include a phase detector configured to receive a reference signal and a feedback signal. The phase detector can be configured to generate a first signal representative of a phase difference between the reference signal and the feedback signal. The control system can further include a charge pump configured to generate a compensation signal based on the first signal. The control system can further includes an oscillator configured to generate an output signal based on the compensation signal. The compensation signal can be configured to reduce or substantially eliminate one or more reference spurs associated with the frequency synthesizer.

Abstract: Disclosed are circuits and method for reducing or eliminating reference spurs in frequency synthesizers. In some implementations, a phase-locked loop (PLL) such as a Frac-N PLL of a frequency synthesizer can include a phase frequency detector (PFD) configured to receive a reference signal and a feedback signal. The PFD can be configured to generate a first signal representative of a phase difference between the reference signal and the feedback signal. The PLL can further include a compensation circuit configured to generate a compensation signal based on the first signal. The PLL can further includes a voltage-controlled oscillator (VCO) configured to generate an output signal based on the compensation signal. The compensation signal can include at least one feature for substantially eliminating one or more reference spurs associated with the PLL.

Abstract: Disclosed are circuits and method for reducing or eliminating reference spurs in frequency synthesizers. In some implementations, a phase-locked loop (PLL) such as a Frac-N PLL of a frequency synthesizer can include a phase frequency detector (PFD) configured to receive a reference signal and a feedback signal. The PFD can be configured to generate a first signal representative of a phase difference between the reference signal and the feedback signal. The PLL can further include a compensation circuit configured to generate a compensation signal based on the first signal. The PLL can further includes a voltage-controlled oscillator (VCO) configured to generate an output signal based on the compensation signal. The compensation signal can include at least one feature for substantially eliminating one or more reference spurs associated with the PLL.

Abstract: Disclosed are systems and method for controlling frequency synthesizers. A control system can be implemented in a phase-locked loop (PLL), such as a Frac-N PLL of a frequency synthesizer, to reduce or eliminate reference spurs. In some embodiments, such a control system can include a phase detector configured to receive a reference signal and a feedback signal. The phase detector can be configured to generate a first signal representative of a phase difference between the reference signal and the feedback signal. The control system can further include a charge pump configured to generate a compensation signal based on the first signal. The control system can further includes an oscillator configured to generate an output signal based on the compensation signal. The compensation signal can be configured to reduce or substantially eliminate one or more reference spurs associated with the frequency synthesizer.

Abstract: Disclosed are systems and method for controlling frequency synthesizers. A control system can be implemented in a phase-locked loop (PLL), such as a Frac-N PLL of a frequency synthesizer, to reduce or eliminate reference spurs. In some embodiments, such a control system can include a phase detector configured to receive a reference signal and a feedback signal. The phase detector can be configured to generate a first signal representative of a phase difference between the reference signal and the feedback signal. The control system can further include a charge pump configured to generate a compensation signal based on the first signal. The control system can further includes an oscillator configured to generate an output signal based on the compensation signal. The compensation signal can be configured to reduce or substantially eliminate one or more reference spurs associated with the frequency synthesizer.

Abstract: Disclosed are circuits and method for reducing or eliminating reference spurs in frequency synthesizers. In some implementations, a phase-locked loop (PLL) such as a Frac-N PLL of a frequency synthesizer can include a phase frequency detector (PFD) configured to receive a reference signal and a feedback signal. The PFD can be configured to generate a first signal representative of a phase difference between the reference signal and the feedback signal. The PLL can further include a compensation circuit configured to generate a compensation signal based on the first signal. The PLL can further includes a voltage-controlled oscillator (VCO) configured to generate an output signal based on the compensation signal. The compensation signal can include at least one feature for substantially eliminating one or more reference spurs associated with the PLL.

Abstract: An integrated circuit superheterodyne radio receiver includes a notch filter coupled with an amplifier for amplifying radio frequency (RF) signals to improve image signal rejection. The notch filter includes a first oscillator circuit with a tank circuit having a resonant frequency corresponding to the unwanted image frequency signal. A control circuit includes a second oscillator circuit, a master bias circuit and a slave bias circuit. The second oscillator circuit is substantially similar to the first oscillator circuit. The master bias circuit is responsive to an amplitude of oscillatory signals in the second oscillator circuit for limiting a flow operating current such that the second oscillator circuit is restrained to operate in a marginally oscillatory state. A slave bias circuit is responsive to the master bias circuit for similarly limiting a flow of current, for operating the first oscillator circuit.

Abstract: With the rising popularity in wireless personal communication systems (PCS), there is a need for low-power, low-cost radio receivers. Low cost can be achieved by integrating the required functions as much as possible, thus minimizing the number of off-chip components. The present invention discloses a novel topology for integrating an image reject filter with a traditional low-noise amplifier (LNA) for use in the front-end of a superheterodyne receiver. Previous topologies employing additional filter stages after the LNA have suffered from poor performance and excessive current consumption. Advantageously, the topology of the present invention requires minimal additional circuitry to perform the filtering function, uses only minimal additional current and does not suffer from the same performance limitations as previous topologies.