354 results about "Fixed capacitor" patented technology

An improved switching regulator for implantable medical devices includes a control circuit with a capacitor divider to conserve energy, and selectable duty cycles to efficiently match the duty cycle to the charge level in a holding capacitor. The switching regulator charges the holding capacitor to commanded voltage levels, and the holding capacitor provides current for tissue stimulation. The commanded voltage level is reached by “pumping-up” the holding capacitor with the output of the switching regulator. For control purposes, the high voltage (i.e., the voltage across the holding capacitor) is divided between a fixed capacitor and a variable capacitor, and the voltage between the fixed capacitor and the variable capacitor (i.e., the divided voltage) is compared to a reference voltage. The result of the comparison is used to turn-off the switching regulator once the commanded voltage level is reached. The switching duty cycle is set to one of two values. At start-up, or when the output voltage drops below a determined threshold, a low duty cycle is used. Once the output voltage reaches the threshold, a higher duty cycle is used.

A gain compensator compensates for the gain variation of a varactor-tuned voltage tuned oscillator (VCO) in a phase lock loop (PLL). The VCO includes a parallel LC circuit having multiple fixed capacitors that can be switched-in or switched-out of the LC circuit according to a capacitor control signal to perform band-select tuning of the VCO. The gain compensator compensates for the variable VCO gain by generating a charge pump reference current that is based on the same capacitor control signal that controls the fixed capacitors in the LC circuit. The gain compensator generates the charge pump reference current by replicating a reference scale current using unit current sources. The number of times the reference scale current is replicated is based on the fixed capacitance that is switched-in to the LC circuit and therefore the frequency band of the PLL. The reference scale current is generated based on a PLL control that specifics certain PLL characteristics such as reference frequency, loop bandwidth, and loop damping. Therefore, the reference pump current can be efficiently optimized for changing PLL operating conditions, in addition to compensating for variable VCO gain.

A tunable capacitor. The tunable capacitor has a first fixed capacitor electrode and a second fixed capacitor electrode opposite to one another. The tunable capacitor also has a movable element formed of a conductive material. The movable element is moveable between the first fixed capacitor electrode and the second fixed capacitor electrode to adjust the capacitance between the first fixed capacitor electrode and the second fixed capacitor electrode.

An antenna for a wireless device may be kept dynamically tuned to a desired center frequency to compensate for detuning which may be caused by environmental influences. A sensor provides a feedback signal to a controller to select an appropriate capacitance value from a variable capacitor to tune the antenna for the wireless device. The variable capacitor may comprise a plurality of fixed capacitors and MEMS switches arranged in parallel or may comprise a variable MEMS capacitor having a fixed lower plate and a flexible upper plate.

A quantum processor is operable as a universal adiabatic quantum computing system. The quantum processor includes physical qubits, with at least a first and second communicative coupling available between pairs of qubits via an in-situ tunable superconducting capacitive coupler and an in-situ tunable superconducting inductive coupler, respectively. Tunable couplers provide diagonal and off-diagonal coupling. Compound Josephson junctions (CJJs) of the tunable couplers are responsive to a flux bias to tune a sign and magnitude of a sum of a capacitance of a fixed capacitor and a tunable capacitance which is mediated across a pair of coupling capacitors. The qubits may be hybrid qubits, operable in a flux regime or a charge regime. Qubits may include a pair of CJJs that interrupt a loop of material and which are separated by an island of superconducting material which is voltage biased with respect to a qubit body.

The invention discloses a self-correcting phaselocked loop frequency synthesizer capable of realizing frequency band selection, composed of a phaselocked loop and a self-correction loop; wherein the phaselocked loop is formed by connecting a phase detection discriminator, a charge pump, a loop filter, a voltage-controlled oscillator and a frequency divider in sequence, the self-correcting loop is formed by connecting a phase detection discriminator, a trigger, a controller, a voltage-controlled oscillator and a frequency divider in sequence, and the phaselocked loop and the self-correcting loop share the same phase detection discriminator, the same voltage-controlled oscillator and the same frequency divider. The invention realizes center frequency correction by regulating one group of fixed capacitor of voltage-controlled oscillator, so that widen frequency tuning range can be obtained under lower gain of voltage-controlled oscillator, thus error caused by making process of integrated inductance and variable varactor can be compensated, phase noise of phaselocked loop frequency synthesizer is reduced, and implementation of single chip phaselocked loop frequency synthesizer by adopting CMOS technology can be realized.

A method for enhancing the linearity of a differential capacitive sensor as a function of beam displacement. An ac-modulated feedback connection from a sensor output terminal to a movable beam electrode is provided through a fix-up capacitor. The output terminal signal is inverted in the feedback connection so that the fix-up capacitor reduces the capacitance from the fixed electrodes to the beam electrode. When the fix-up capacitor value is chosen approximately equal to the fixed capacitance of the differential capacitor, the feedback circuit compensates for the effect of this fixed capacitance. The linearity of the output as a function of the displacement of the beam is improved. Thus, the signal-to-noise ratio of devices such as accelerometers may be increased by allowing sensors to employ a large displacement range. The invention may be used in differential accelerometers and in other types of differential capacitive sensors.

A frequency synthesizer, a calibrator thereof, and an operating controller thereof are described. The synthesizer comprises a main charge pump that drives a voltage controlled oscillator (VCO) through a loop filter. The calibrator includes a second, replica charge pump that can also drive the VCO, but is set up to output only its maximum or minimum analog output control voltage. Since the construction and characteristics of the replica charge pump duplicate the main charge pump, the main charge pump's minimum and maximum analog control outputs can be cloned out to the VCO on demand. A VCO calibration procedure therefore includes switching the VCO to each of its ranges set by a bank of fixed capacitors, and using the replica charge pump to drive the VCO to its minimum and maximum frequency for each range setting. The min-max frequency data is stored in a lookup table, and operational requests to switch to a new channel frequency can be supported with a priori information about which fixed-capacitor range selection will be best. The operating point controller includes a sensor to sense the operating point and a controller that provides a switching input to a switchable bank of capacitors to change the operating point. The change can be determined according to calibration data.

A capacitor module is provided with a plurality of capacitor cells each having a capacitor and a capacitor case provided with a first closed-bottomed screw hole with an opening on a bottom surface for housing the capacitor, a metallic cell-fixing body having a through-hole in communication with the first screw hole to which the capacitor cells are fixed by inserting a cell screw in the through-hole and the first screw hole, an insulator made of a thermally conductive insulating material and provided between the capacitor cells and the cell-fixing body for insulating the capacitor cells from the cell fixing body, and a metallic heat-dissipating body having a second closed-bottomed screw hole in which a cell-fixing body screw is inserted and having a flow passage for causing a cooling medium to flow on a rear surface side of a surface on which the second screw hole is provided.

The invention provides a two-phase flow parameter measurement method based on a dual-head capacitance probe and a device thereof, belonging to the field of multi-phase flow testing technology. The device comprises the dual-head capacitance probe, a probe driving mechanism, two capacitance measurement circuits, a fixed capacitor, a slab electrode and a computer system; wherein, the dual-head capacitance probe system consists of two independent single-point capacitance probes and can carry out one-dimensional motion on the section of a pipeline. The method comprises the steps as follows: each single-point capacitance probe is used for recognizing fluid property; when the fluid passing through the head of the probe is conducted, the circuit is connected and the capacitance measurement device outputs high level, otherwise the circuit is cut off and the capacitance measurement device outputs low level. The level signal can obtain local phase holdup; the measurement result of the method is not affected by the conductivity of the fluid and the spacing of the probes. The local phase holdup and the flowing speed can be obtained by processing the two single-point capacitance probe signals by the threshold method and the correlation method; the flowing pattern information can be obtained by combining with two-phase flow knowledge, thus achieving the recognition of flow pattern on line.

An automatic tuning system for a magnetic field generating tuned circuit includes a processor configured to maintain the resonant frequency of a tuned circuit equal to a reference frequency. The tuned circuit is driven by a power amplifier whose output provides an amplified signal at the reference frequency. The tuned circuit includes a magnetic field generating inductor and a bank of individually switchable capacitors controlled by the processor capable of adding and removing the respective capacitances to and from the tuned circuit. The inductor includes a Faraday shield to shield the tuned circuit from the influence of electric fields. In an embodiment of the invention, the variable capacitor is in the form of a diode variable capacitor (varicap) in parallel circuit relationship with the tuned circuit capacitor and the inductor. In an alternate embodiment the inductor and a fixed capacitor are in series circuit relationship with the varicap in parallel circuit relationship with the fixed capacitor and the tuning sequence relies on a phase locked loop using the phase of a reference frequency signal and the phase of the inductor voltage as control parameters.

The invention provides a voltage controlled oscillator (VCO) capable of adjusting the linearity of a gain and a two-point modulator based on the VCO. The two-point modulator is based on a phase-locked loop (PLL) circuit, wherein a control voltage of the VCO consists of two parts, namely a loop feedback control signal and a modulation control signal. For the modulation control signal, by connecting two or more groups of varactors in parallel and applying different direct current bias voltages, the mismatching of modulation gains is reduced because the varactors have the characteristic of adjusting the linearity of a frequency-voltage gain of the VCO; and each group of varactors is connected with a fixed capacitor in parallel, so the mismatching of a manufacturing process of the varactors can be reduced. By adoption of the circuit structure, the modulation error of the two-point modulator can be reduced.

The invention discloses a transmission line, a leaky-wave antenna multiplexing device and a beam scanning method thereof. The device comprises a dielectric substrate, a metal strip and a metal floorboard positioned on the front and back surfaces of the dielectric substrate, and periodically alternatively arranged capacitors and variable capacitance diodes for connecting the metal floorboard and the metal strip via the through holes. The metal strip comprises gradient microstrip line structures at two ends and an artificial surface plasmon structure positioned therebetween. When the capacitance value of the variable capacitance diode is identical with that of the fixed capacitor, the surface impedance of the device is identical, and thus the function of the transmission line is achieved; when the capacitance value of the variable capacitance diode is not identical with that of the fixed capacitor, the surface impedance of the device is periodically modulated, and thus the radiation function of the leaky-wave antenna is achieved. Voltage is used as a regulation means, and fixed frequency beam scanning can be achieved along with the change of the voltage; the device is simple to manufacture, convenient to operate and prone to integrate; only a photoetching step is needed, so that cost is saved, and machining errors caused by a multi-layer structure are avoided.

An accelerometer open loop control system comprising a variable capacitance accelerometer having a proof mass movable between fixed capacitor plates, drive signals applied to the capacitor plates, a charge amplifier amplifying an accelerometer output signal representing applied acceleration, and an autoranging facility for monitoring the output signal, and for adjusting the drive signals in dependence on the output signal in order to restrict the amplitude of the accelerometer output signal, thus maintaining sensitivity of the accelerometer while permitting response to a wide range of g values. Corrections are applied by means of look up tables to compensate for inaccuracies arising from movement of the proof mass and temperature variations.

The charge-pump output high-pressure controlling device comprises a reference voltage producing circuit which consists of a reference voltage-current source and a mode producing circuit, external regulation signals are input into the reference voltage-current source which outputs two reference voltage signals to be accessed to the input end of the mode producing circuit. External enable signal is accessed into the input end of the mode producing circuit which outputs then the output signal of the reference voltage producing circuit. Advantage: reference voltage with specific rise-time and retention time which can be changed by regulating the reference current for charging a fixed capacitor or the capacitance value; The change of rise-time and retention time of reference voltage is small in all range of working temperature when ADJ set value is not changed, so that the high-voltage output by charge pump has same mode and the peak value of it is stable.

The invention provides a same-phase traction power supply system suitable for a high-speed electrified railway, and belongs to the technical field of traction power supply and electric power transmission and distribution. The same-phase traction power supply system includes traction transformers and a same-phase compensator which are mutually independent, and the traction transformers and a compensation transformer and a matching transformer in the same-phase compensator are of single-phase structures. The primary windings of the traction transformers and the primary winding of the compensator transformer form V, and a connection method of V is as follows: one end of the primary winding of the matching transformer is connected with one end of the secondary winding of the compensation transformer, and other end of the primary winding is connected to the positive electrode of a traction busbar; the other end of the secondary winding of the compensation transformer is connected to the ground or the negative electrode of the traction busbar, alternating current ports of one side of ''back-to-back'' converters are connected to the secondary winding of the compensation transformer, and the other side is connected to the secondary winding of the matching transformer; and the same-phase compensator adopting hybrid compensation configuration also includes a fixed capacitor branch circuit and a fixed reactor branch circuit. The same-phase traction power supply system suitable for the high-speed electrified railway can achieve an effect that the capacity of both active and passive compensation devices is the lowest configuration, and a relatively high capacity utilization rate of the transformers is maintained at the same time.

The present invention is an electronic height gauge utilizing new technology and includes a first column (Column 1) and a second column (Column 2), a display unit with a cover, a measuring scriber, a fixed capacitance sensor and a linear moving capacitance sensor. The fixed capacitance sensor is located on a flat surface on Column 1, flat surface having a length equivalent to the length of Column 1. The linear moving capacitance sensor is located inside the display unit cover positioned to face the fixed capacitance sensor. The fixed capacitive sensor and linear moving capacitive sensors are facing toward each other only, and do not make direct physical contact with the fixed capacitor sensor when the height gauge is operating in upward and downward movements. The fixed and moving capacitive sensors are instead making only electrical contact with each other when the height gauge is making upward and downward movements. This linear direct data non-contact sensor transfer system results in high accuracy of measurements, which also ensures the repeatability of accurate measurements. Also, since the fixed capacitance sensor and the linear moving capacitance sensor have no physical contact with each other, there is no wear and tear damage on either component part, thereby leading to a longer life of use with stability in accurate measurements and repeatability. Because the measuring system is comparatively simple, and easy to assemble and service and maintain compared to the existing rotary capacitive sensor electronic height gauges that exist on the market, the overall cost of production and maintenance is minimized. On the second column (Column 2), a simple rack and gear system is added. These gears of column 2 are connected to a hand wheel located on the rear of the display unit. The handwheel is used for making upward and downward vertical movements. This rack and gear system of column 2 of the present invention is only used to aid the same in making upward and downward movements, and does not affect the measuring accuracy of the height gauge, as it did in the height gauges that have existed on the market.

A MEMS capacitive device (90) includes a fixed capacitor plate (104) formed on a surface (102) of a substrate (100). A movable capacitor plate (114) is suspended above the fixed capacitor plate (104) by compliant members (116) anchored to the surface (102). A movable element (120) is positioned in spaced apart relationship from the movable capacitor plate (104) and has an actuator (130) formed thereon. Actuation of the actuator (130) causes abutment of a portion of the movable element (120) against a contact surface (136) of the movable plate (114). The abutment moves the movable plate (114) toward the fixed plate (104) to alter a capacitance (112) between the plates (104, 114). Another substrate (118) may be coupled to the substrate (100) such that a surface (126) of the substrate (118) faces the surface (102) of the substrate (100). The movable element (120) may be formed on the surface (126).

Improved dispersion compensating circuits for optical transmission systems are disclosed. According to the improved method, there is provided a compensation circuit comprising a varactor diode network. The network is preferably inserted between a source of laser modulating signal and the laser. A low-pass filter or all pass filter constructs the network. The network preferably includes an inductor or inductors and a combined circuit, which includes varactors. The network preferably provides an amplitude dependent delay of the modulating signal applied to the laser or to the optical receiver as post dispersion correction circuitry. In a first embodiment, a fixed capacitor is in series with a varactor and connected to a DC bias through inductor. Additional embodiments, using multiple varactors in different circuit configurations, with particular advantages for various applications identified.

The invention relates to a static reactive power compensator adjusting method used in power transmission system. It comprises three combined regulation control tactics: it controls the reactor (TCR) antennal organs which is controlled by the bus wire thyristor to do perceptual reactive-load power constant adjustment; it controls the power filter device group (FC) and the fixed condenser band to do condenser reactive-load power interval adjustment; it controls the load transformer tapping switch (LTC) to do bus wire adjustment.

Various embodiments of tunable capacitors are disclosed. One embodiment is in the form of a tunable capacitor (368) having a pair of stationary capacitor electrodes (392) that are fixed to and disposed the same distance above a substrate (388) in the vertical dimension. A tuning element (416) is suspended above the substrate (388) by an elevation system (460) that accommodates movement of the tuning element (416) in the vertical dimension. Changing the capacitance of the tunable capacitor (368) is accomplished by moving the tuning element (416) in the vertical dimension.

There is provided a variable device circuit according to the present invention, including: a substrate; at least one movable switch device formed on a first principal surface of the substrate; at least one fixed capacitor device formed on the first principal surface of the substrate; at least one variable capacitor device formed on the first principal surface of the substrate; at least one variable inductor device formed on the first principal surface of the substrate; and wiring lines for electrically connecting the devices to one another, the wiring lines being formed on the first principal surface of the substrate; wherein electrical connections among the devices can be selected by operation of the movable switch device, whereby achieving stable, low-loss circuit characteristics with lower manufacturing cost.

A voltage controlled oscillator, includes a tank circuit including an inductor having a value L, interconnected with first and second variable capacitors, having values CVAR1 and CVAR2, and a fixed capacitor CFIXED, to cause oscillation of the oscillator at a controlled frequencyfosc=2π(L{CVAR2+CFIXEDCVAR1CFIXED+CVAR1})-1 / 2CVAR1 controls coarse frequency tuning of the oscillator, and CVAR2 may control fine tuning of the oscillator. The variable capacitors may be formed using accumulation-mode MOS varactors

The present disclosure provides a method of performing a plasma processing on a substrate by using a plasma processing apparatus including a processing container; an outer upper electrode provided to face a lower electrode; an inner upper electrode disposed inside the outer upper electrode; a first high-frequency power supply; a first power feeding unit; a second power feeding unit; and a variable condenser. The first and second power feeding units, a fixed condenser formed between the outer upper electrode and the inner upper electrode, and a closed circuit including the variable condenser become a resonance state when the variable condenser has a capacitance value in a predetermined resonance region. The method includes selectively using a capacitance value in a first region lower than the resonance region of the variable condenser and a capacitance value in a second region higher than the resonance region to perform the plasma processing.

The invention discloses a triangular connection type comprehensive compensation system integrated with a cascaded active filter and a reactive compensator. The system comprises triangular connection type N-grade cascaded converters and a three-phase filter inductor connected with each N-grade cascaded converter; triangular connection type thyristor reactors and star-shaped connection type thyristors are used for switching the reactive compensator composed of fixed capacitors; and the triangular connection type N-grade cascaded converters and the reactive compensator are connected in parallel between a connection node and a ground node of an input power grid voltage and a load. According to the system provided by the invention, reactive power and harmonic current in a medium-voltage power grid are subjected to dynamic compensation and the efficiency of the power grid is improved; when the system is used for compensating, the system has no negative influences on the power grid, and has advantages of stable system, simple structure, strong stability and flexibility in compensation.

To provide a voltage controlled variable capacitor which can change a capacitance value thereof in a wide controlled voltage range and control the capacitance value easily with a high precision without complicating the circuit configuration thereof, and to provide a voltage controlled variable capacitor which can change a capacitance value thereof with a good linearity. The voltage controlled varactor is configured in a manner that varactors VCk, each formed by a series connection of a fixed capacitor Ck (k=1, 2, - - - , n) and a MOS transistor Mk of N channel type, are connected in parallel. The MOS transistors M1 to Mn are configured in a manner that gate widths W are same but gate lengths L1 to Ln are elongated sequentially (that is, L1<L2< - - - <Ln) so that the threshold voltages thereof are differentiated from one another.