32results about "Variable-capacitor element amplifiers" patented technology

A method for calibration of a magnetic resonance imaging system having a bore, a body coil mounted in the bore, a patient mat, a number of local coils mounted in the patient mat, an upconversion stage having a number of upconverters, and a processing stage, includes the steps of generating a calibration signal in the body coil; receiving the calibration signal at the local coils, upconverting the signal from the local coils in the upconversion stage, transmitting the upconverted signal to the processing stage, synchronously downconverting the signal in the processing stage using the calibration signal generated in the body coil, and processing the downconverted signal to generate an overall path complex gain.

A two port parametric amplifier has a first port that receives an input signal to be amplified and upconverted and a second port that receives a local oscillator signal. The amplified upconverted input signal is emitted as an output at upper and lower sideband frequencies. The amplifier further has a pair of varactor diodes connected between the first port and the second port. The diodes are connected in parallel from the first port and in series from the second port.

Embodiments of the present invention provide a device with an integrated low-noise parametric amplifier using a CCD-based structure with minimal noise gain. In one embodiment, a device which may be used for monitoring and/or diagnosing a human or an animal body comprises a CCD-based device including a first gate forming a first capacitor and a second gate forming a second capacitor, the first capacitor having a surface area larger than a surface area of the second capacitor; and a controller configured to input a signal to the CCD-based device; convert the input signal into a charge packet having a voltage associated therewith; transfer the charge packet from the first capacitor to the second capacitor of the CCD-based device, the voltage associated with the charge packet being multiplied by a ratio of the surface area of the first capacitor divided by the surface area of the second capacitor; and produce an amplified output signal from the multiplied voltage.

The invention discloses a Josephson traveling wave amplifier and a preparation method thereof. The Josephson traveling wave amplifier comprises two metal layers and an intermediate dielectric layer; the first metal layer is an aluminum film, and a lower panel, an inductor and a ground plane of the capacitor are prepared through ultraviolet lithography; a second metal layer is used for preparing anupper panel of the Josephson junction and the capacitor through double-angle evaporation; the intermediate dielectric layer completely covers the first metal layer by using an aluminum oxide film grown by monoatomic layer deposition; wherein the Josephson structures form a transmission line, and two ends of the transmission line respectively form an input port and an output port of the Josephsontraveling wave amplifier; the Josephson junctions are connected with the ground through plate capacitors, and coplanar waveguide lines are adopted for connection at the bent positions of the transmission lines. By adopting the Josephson traveling wave amplifier provided by the invention, the material loss can be reduced, the preparation process is simplified, and the yield of device preparation isimproved.

The invention discloses a quantum parameter amplifier, the quantum parameter amplifier comprises a capacitor module for forming an oscillation amplification circuit, a reflection type microwave resonant cavity and an inductance-adjustable superconducting quantum interference device which are connected in sequence; one end, far away from the reflection type microwave resonant cavity, of the superconducting quantum interference device is grounded; the resonant frequency of the reflection type microwave resonant cavity is equal to the frequency of a signal to be amplified by adjusting the inductance of the inductance-adjustable superconducting quantum interference device; a signal to be amplified is coupled into the oscillation amplification circuit from the capacitor module; the oscillationamplification circuit is used for amplifying the signal to be amplified under the action of the pumping signal, and a plurality of idle frequency signals are generated; a second microwave resonant cavity is included and is connected to the end, away from the capacitor module, of the reflection type microwave resonant cavity, the resonant frequency of the second microwave resonant cavity is equal to the frequency of one idle frequency signal, and the frequency of the pumping signal, in the optimal working mode, of the quantum parameter amplifier does not need to be selected as the frequency multiplication of the to-be-amplified signal.

According to an example aspect of the present invention, there is provided a traveling wave parametric amplifier comprising a waveguide transmission line comprising therein at least ten Josephson elements, wherein each of the at least ten Josephson element comprises a loop, with exactly one Josephson junction of first size on one half of the loop and at least two Josephson junctions of a second size on a second half of the loop, the second size being larger than the first size, a flux bias line configured to generate a magnetic flux threading each of the at least one loop, and a set of resistors coupled with the flux bias line.

An RF receiver circuit configuration and design is limited by conditions and frequencies to simultaneously provide steady state low-noise signal amplification, frequency down-conversion, and image signal rejection. The RF receiver circuit may be implemented as one of a CMOS single chip device or as part of an integrated system of CMOS components.

A PWM cycloconverter easily capable of improving an input current waveform and regenerating energy of a snubber into a power source is provided. A PWM cycloconverter includes a PWM converter connected to a DC voltage system. An output unit of the PWM converter is connected to a place before an input filter of the PWM cycloconverter to keep down resonance of the input filter.