Abstract: The method includes an adjustment phase in which a filtering device is operated as an oscillator, the frequency of oscillation of the filtering device is determined, and the characteristics of the filtering device are corrected with respect to the determined oscillation frequency and to a pre-established relation between the frequency of oscillation and the theoretical cutoff frequency, in such a way as to confer upon the filtering device a cutoff frequency equal to the theoretical cutoff frequency to within a tolerance. After the adjustment phase, a working phase takes place in which the filtering device carries out its filtering function.

Abstract: The amplifier of the present invention causes variations in the rail voltage that are controlled by the frequency of the audio signal being amplified as the audio signal changes. This is done to tune the operation of the amplifier taking into consideration the frequency response of the human ear. By doing so, the resulting amplifier is more efficient at lower frequencies where more signal distortion is required before it can be heard by the human ear, and a higher quality signal output is provided at higher frequencies where the human ear can more readily detect distortion. Thus by designing the amplifier from the listener's point of view results in an amplifier with much improved performance from both technical and listener points of view.

Abstract: At least one amplifier is selected from a first bank of non-linear amplifiers. At least one amplifier is selected from a second bank of non-linear amplifiers. The number of amplifiers selected from the first and second banks remains constant. Using the selected amplifiers, first and second components of a digital symbol are amplified using the first and second banks, respectively. The outputs produced by first and second banks are combined to produce an analog representation of the digital symbol.

Abstract: A transimpedance amplifier (18) receives an audio signal from a power audio amplifier (14) and provides a variable power level to a loudspeaker (16). A first variable gain amplifier (28) receives the audio signal and provides a variable gain to a power amplifier (40). The output signal of the power amplifier drives the loudspeaker. A sense amplifier (52) subtracts a voltage representative of current flowing through the loudspeaker from a voltage applied to the loudspeaker and provides a difference signal. A second variable gain amplifier (70) receives the difference signal and provides a variable gain to a load amplifier (80). The gains of the first and second variable gain amplifiers are inversely proportional. A resistive element (84) having a real impedance is coupled between an output of the load amplifier and the input of the transimpedance amplifier to maintain the complex impedance of the loudspeaker at the output of the power audio amplifier.

Abstract: Disclosed is a transimpedance amplifier comprising a multistage amplifier and a feedback circuit coupled between a single ended input terminal and one of a plurality of differential output terminals of the multistage amplifier. The feedback circuit may control an input voltage at the single input terminal to substantially maintain a set or predetermined transconductance between the single ended input terminal and the differential output terminals.

Abstract: A method and apparatus is provided for use in power amplifiers for reducing the peak voltage that transistors are subjected to. A power amplifier is provided with first and second switching devices and an inductor connected between the switching devices. The switching devices are driven such that the switching devices are turned on and off during the same time intervals.

Abstract: The present invention discloses a distributed power amplifier topology and device that efficiently and economically enhances the power output of an RF signal to be amplified. The power amplifier comprises a plurality of push-pull amplifiers interconnected in a novel circular geometry that preferably function as a first winding of an active transformer having signal inputs of adjacent amplification devices driven with an input signal of equal magnitude and opposite phase. The topology also discloses the use of a secondary winding that matches the geometry of primary winding and variations thereof that serve to efficiently combine the power of the individual power amplifiers. The novel architecture enables the design of low-cost, fully-integrated, high-power amplifiers in the RF, microwave, and millimeter-wave frequencies.

Abstract: An automatic gain control device without being influenced by leakage current of a capacitor. The automatic gain control device includes a first control loop, a second control loop, and a multiplexer. The first control loop receives an input voltage and generates a first AGC voltage accordingly. The second control loop receives the first AGC voltage, registers the first AGC voltage as digital data, and outputs a second AGC voltage by a DAC. The multiplexer chooses the first AGC voltage or the second AGC voltage as an AGC voltage according to a hold signal. Because the second control loop registers the first AGC voltage in a digital format and output the second AGC voltage from the DAC, the AGC voltage can be held constant for a long time without being influenced by leakage current.

Abstract: A low quiescent power class AB current mirror circuit includes a first input transistor for receiving an input current and a second output transistor for providing an output current; the first and second transistors having bases connected together; and a first current supply for sinking current from the bases in response to a decrease in input current to lower the quiescent point of the transistors.

Abstract: An improved bipolar transistor power amplifier circuit including a bias input node, an RF input node, an RF output node, and a plurality of HBTs. Each HBT includes a base, an emitter, a collector, a base resistor connected to the base and selected to offset a portion of the voltage drop across the base and emitter of each transistor, an emitter resistor connected to the emitter, and a base capacitor having two electrodes one of which is coupled to the base. The HBTs are grouped together in two or more groups and each group includes a base resistor selected to offset another portion of the voltage drop across the base and emitter of the transistors.

Abstract: The present invention, generally speaking, provides for high-efficiency power control of a high-efficiency (e.g., bard-limiting or switch-mode) power amplifier in such a manner as to achieve a desired control or modulation. Unlike the prior art, feedback is not required. That is, the amplifier may be controlled without continuous or frequent feedback adjustment. In one embodiment, the spread between a maximum frequency of the desired modulation and the operating frequency of a switch-mode DC-DC converter is reduced by following the switch-mode converter with an active linear regulator. The linear regulator is designed so as to control the operating voltage of the power amplifier with sufficient bandwidth to faithfully reproduce the desired amplitude modulation waveform. The linear regulator is further designed to reject variations on its input voltage even while the output voltage is changed in response to an applied control signal.

Abstract: A power amplifier module is provided with a function of protecting an amplifying device against destruction caused by a standing wave by reflection from an antenna end in load variation. Increase in base current from idling current of a final stage amplifying portion GaAs-HBT in load variation is detected and canceled and collector current is restrained to thereby prevent an increase in output and prevent destruction of GaAs-RET. By also using a function of successively lowering idling current when power source voltage is elevated and a clipping function of diodes connected in parallel with output stage GaAs-RET, voltage as well as current more than necessary are avoided from being applied on the output stage GaAs-RET.

Abstract: In a phase-locked loop, multiple input clock references can each connect to a different interface card. Each interface card can include a phase comparator portion of a phase-locked loop. The phase comparators can produce a phase error signal for a phase-locked loop. One or more of the phase error signals can be transmitted across a bus, such as a time division multiplexed bus, to a system card. The system card can include a controlled oscillator portion of the phase-locked loop. The output of the system card can then sent back to one or more of the interface cards to complete the phase-locked loop.

Abstract: A method for automatically calibrating a phase locked loop (PLL) system includes estimating a frequency value of an input signal applied to the system. Based on the estimated frequency value, a driving signal is generated for a plurality of internal switches in the PLL system. A PLL system may also implement this automatic calibration method.

Abstract: Timing signal generation and distribution are combined in operation of a signal path exhibiting endless electromagnetic continuity affording signal phase inversion and having associated regenerative active means. Two-or more-phases of substantially square-wave bipolar signals arise directly in travelling wave transmission-line embodiments compatible with semiconductor fabrication including CMOS. Coordination by attainable frequency synchronism with phase coherence for several such oscillating signal paths has intra-IC inter-IC and printed circuit board impact.

Abstract: A multi-band local oscillator for generating an output oscillator signal of a desired frequency is implemented with a single voltage controlled oscillator providing an input oscillator signal and a switch divider block. The output signal is passed through a selected one of a set of filters for band switching and through a frequency divider and subsequently mixed with the input oscillator signal of the voltage controlled oscillator.

Abstract: An improved oscillator system has a control logic block which has an input from an external device to which clock is being provided. The input controls a counter which counts cycles from the oscillator. If some predetermined number of cycles has passed in the absence of a predetermined input condition, then the oscillator halts, thus reducing power consumption by the oscillator system. Later, upon the predetermined input condition, the oscillator resumes oscillation. The system has improved noise immunity and permits a continuous-oscillation mode without the need of an extra pin or memory bit. The control logic block may also employ a counter which counts the number of times the predetermined input condition has occurred, and only after some predetermined number of occurrences does the oscillator-halting activity take place.

Abstract: An oscillator transmission switching circuit switches between asynchronous oscillator signals with low latency. Preferably, a fast switching circuit triggers a transition from a first oscillator to a second oscillator by entering a bridge input immediately following an edge of the first oscillator, holding in the bridge input until the same edge of the second oscillator is detected, and switching to the second oscillator. Preferably, the bridge input is selectable to accommodate conditions in which the first oscillator signal is stuck at either a logic 0 or a logic 1. A change of oscillators may be triggered by a fault detection circuit or by an external signal.

Abstract: An oscillator circuit is specified, having an LC resonator, to which two or more current paths are connected, which are connected in parallel with one another and can be connected and disconnected individually by switches. The attenuation compensation amplifiers are in this case coupled to the resonant circuit in order to compensate for its attenuation. The oscillator circuit allows the gradient of the compensation for the attenuation of the resonant circuit to be adjusted, without moving the operating point of the amplifiers. This makes it possible to compensate for manufacturing-dependent component tolerances and any amplitude discrepancy caused by them, in a simple way. The oscillator circuit is suitable, for example, for use in voltage-controlled oscillators in order to form phase-locked loops when using mass production technologies.

Abstract: A low cross talk compensation circuit comprising a first signal pair having a first conductor and a second conductor parallel to the first conductor, and a second signal pair having a third conductor and a fourth conductor parallel to the third conductor, wherein each conductor is attached to a corresponding input signal. A first compensation line attached to the first input signal and a second compensation line attached to the third input signal are intertwined forming a first compensation line assembly with capacitive and inductive coupling parallel to and flanked by the second and third conductors. A third compensation line attached to the fourth input signal and a fourth compensation line attached to the second input signal are intertwined forming a second compensation line assembly with capacitive and inductive coupling parallel to and adjacent to the second conductor.

Abstract: A selectable waveguide transitions between two positions to at least two independent signals by their polarization or frequency. This waveguide consists of dissimilar wave sections coupled to an antenna feed and is mechanically actuated for signal selection switching to route signals to output ports and respective probes that are polarization sensitive. The waveguide sections offer high polarization purity so that signal components remain separated to avoid mutual interference and low insertion loss to maintain system efficiency. Selectable waveguide can be extended for multiple polarization and frequency operation. Frequency selective surfaces and tapers establish pass bands and attenuation levels for frequency selection. The selectable waveguide is suitable for both frequency and polarization selectively in antenna system.

Abstract: A three-port nonreciprocal circuit device has a structure in which one end of a first center electrode is electrically connected to an input external terminal via an input port, and the other end thereof is electrically connected to a ground external terminal. One end of a second center electrode is electrically connected to an output external terminal via an output port. The second center electrode and a matching capacitor constitute an LC parallel resonator circuit. A series inductor is electrically connected between the LC parallel resonator circuit and the ground external terminal. One end of a circuit center electrode is electrically connected to a third port. A matching capacitor and a terminating resistor constitute a parallel RC circuit, which is electrically connected between the third port and ground.

Abstract: A multilayer substrate ensuring transmission loss as low as when one double-sided substrate is used, while reducing noise, and an LNB converter are provided. The multilayer substrate includes a four-layer substrate having pattern layers sandwiching dielectric layers therebetween. The surface pattern layer provided with a signal line of the microstrip line has a projecting portion. The pattern layer provided with a ground pattern corresponding to the signal line has a portion at least overlapping a root portion of the projecting portion as seen from the top and constituting a surface layer on the other side opposite to the root portion, with no other pattern layer interposed between the relevant portions.

Abstract: An apparatus for matching the impedance of an RF generator to the impedance of an RF load, for use in manufacturing semiconductor devices by using a plasma. The apparatus includes a variable inductor coupled to a variable capacitor and an invariable capacitor, the variable inductor having two inductors coupled electrically with each other in series and disposed adjacent to each other. At least one of the two inductors is disposed movably to make the magnetic flux of the one inductor interfere with the magnetic flux of the other inductor, thereby to control the inductance of the variable inductor. In the case of a plasma enhanced semiconductor wafer processing system, the apparatus can reduce the time necessary to achieve an RF match between the RF generator and the RF load, thereby increasing the life of the apparatus.

Abstract: An impedance matching circuit for providing a lossless target signal transmission and rejecting image signals of heterodyne and super-heterodyne transceiver. The impedance matching circuit includes a grounded metal membrane, a first microstrip line connected with an input circuit, a second microstrip line connected with an output circuit, and a third microstrip line connected with either the first microstrip line or the second microstrip line. The first microstrip line is not connected with the second microstrip line, and the length of the third microstrip line is equal to a quarter wavelength of an image signal. When the target signal and the image signal transmit to the impedance matching circuit, the image signal will bypass to a grounded metal membrane, and the target signal will transmit to the output circuit without signal decay through electromagnetic coupling of the first microstrip line and the second microstrip line.

Abstract: A transmission line includes a signal conductor and at least one varactor diode capacitively coupled to the signal conductor. The transmission line's signal path delay is a function of its shunt capacitance, and the varactor's capacitance forms a part of the transmission line's shunt capacitance. The transmission line's signal path delay is adjusted by adjusting a control voltage across the varactor diode thereby to adjust the varactor diode's capacitance.

Abstract: A laminated low-profile dual filter module for telecommunications devices and method provides both Groupe Spécial Mobile (GSM) and Digital Cellular System (DCS) transmit filters in a small package. The filter module comprises multiple layers of ceramic substrate with metal circuit patterns sandwiched between. Two separate filters are implemented within the layers, with a first filter comprising a first set of layers and the second filter adjoining within a second set of layers. Resonators for each filter are positioned at the opposite sides of the module, in order to avoid coupling between the resonators and ground layers are interspersed for isolation. Capacitors are implemented by a first plate defined by an area on one metal layer with the adjacent layers providing ground planes that form the second plate.

Abstract: An electromagnetic filter has a pair of solder-in filters assembled together outside of a filter housing, inserted into, and soldered to the filter housing. The solder-in filters have a metal casing and a capacitor encapsulated within the metal casing and attached to the metal casing. A glass hermetic seal on one end of the solder-in filters reduces the risk of moisture entering the filter during the testing process and adversely affecting the electrical properties of the filter.

Abstract: An electronic part such as a dielectric duplexer or filter is provided which comprises a dielectric ceramic block having a pair of opposite first and second side surfaces and an end surface meeting the first and second side surfaces nearly at right angles, an extension-electrode forming notch formed in the end surface so as to have an open end at the first side surface, a dummy electrode-forming notch formed in the end surface so as to have an open end at the second surface, the extension electrode-forming notch and the dummy electrode-forming notch corresponding in shape and position when observed in the direction in which the first and second side surfaces are opposed, an extension electrode formed in the extension electrode-forming notch, and a dummy electrode formed in the dummy electrode-forming notch. A method of forming an electrode of such an electronic part is also provided.

Abstract: A film bulk acoustic resonator may be formed with a piezoelectric film having improved quality. The piezoelectric film may be deposited directly onto a single crystal silicon substrate. That substrate may be removed and selectively replaced with a lower electrode to form the film bulk acoustic resonator.

Abstract: A SAW filter includes a plurality of IDTs arranged on substrate along a SAW propagation direction, and balanced signal terminals connected to an IDT. The SAW filter is a floating balanced type. The plurality of IDTs are arranged so as to provide a horizontally asymmetrical structure with respect to an imaginary axis that is positioned at the approximate center of the center IDT in the SAW propagation direction and which is substantially perpendicular to the SAW propagation direction. Thus, a SAW filter having filtering characteristics and a balance-to-unbalance conversion function is achieved with high balance between the balanced signal terminals.

Abstract: A high frequency filter kit in which resonating first and second electrical circuits are enclosed between proximal and distal ends of a filter case. Partitioning the inside of the enclosed resonant circuits may be performed by a user to form at least a first cavity and a second cavity. The first resonating circuit is then disposed inside the first cavity of the filter case extending from the proximal end towards the distal end, and the second resonating circuit is disposed inside the second cavity also extending from the proximal end towards the distal end. Electrical signals are coupled into the resonating circuits by an encased signal coupler which is removably mounted by a coupling housing for supporting the signal coupler at the proximal end of the filter case for positioning in the vicinity of the resonating circuits.

Abstract: A YIG film formed on a GGG substrate is separated by a stepwise groove for preparing YIG films having different intervals between end surfaces, and two YIG films resonating magnetostatic waves between the end surfaces having different intervals are coupled with each other thereby forming a resonator.

Abstract: Support structure for high frequency coaxial transmission line. A conductive bead ring is split in two halves longitudinally, containing a relief for excess glass flow and provision for locking the halves together. A glass dielectric surrounds the center conductor, which is tapered from a first larger diameter to a second smaller diameter in the region of the glass dielectric. A fixture for forming the glass to metal seal uses dams to control the positioning of the glass with respect to the taper in the center conductor.

Abstract: A broadband coaxial transmission line is formed by joining smaller coaxial transmission lines having particularly formulated lengths. Insulating supports in the transmission line are situated in a prescribed manner to reduce reflections along the transmission line. The insulating supports are also formed with particularly positioned symmetric voids to minimize weight, provide adequate structural support, and minimize reflections.

Abstract: A microwave monolithic integrated circuit (MMIC) assembly and related method are disclosed. A dielectric substrate has a surface on which radio frequency circuits and microstrip lines are formed. At least one MMIC chip opening is dimensioned for receiving therethrough a MMIC chip. A metallic carrier is mismatched as to coefficient of thermal expansion to the dielectric substrate and includes a component surface adhesively secured to the dielectric substrate on the surface opposing the radio frequency circuits and microstrip lines. At least one raised pedestal is on the component surface that is positioned at the MMIC chip opening. A MMIC chip is secured on the pedestal and extends through the MMIC chip opening for connection to the radio frequency circuits and microstrip lines. Stress relief portions are formed in the metallic carrier that segment the carrier into subcarriers and provide stress relief during expansion and contraction created by temperature changes.

Abstract: An “inside out” process is used to make RF antennas and components or higher frequency components and/or optics. An electroformed single or multi layer of metal, such as copper, is applied to a reusable or disposable mandrel. Additional metal or composite components and/or pieces may be attached to the electroform by means of further electroforming, and/or applying adhesive and/or soldering. Any composite material (for example, fiberglass or carbon fiber reinforced plastic) is then applied selectively or uniformly around the electroform and/or additional components for structural reinforcement, and/or enhancement of thermal stability and/or thermal conductivity. The mandrel is then removed by physical or chemical means. Adhesion over temperature and humidity extremes, surface finish, uniform metalization thickness, and surface electrical conductivity are all vastly improved over equivalent electroplated composites.

Abstract: A wave-guide having at least two connection points. In order to adapt a physical distance between these points to a variable distance between connection points of external equipment, at least one connector (20) is provided having a first connecting member (31) for connection to a connection point (28) of the wave-guide and a second connecting member (33) for connection to a connection point of the external equipment. The connecting members of the connector are laterally displaced such that rotation of the second connecting member (33) about the first one (31) results in a variation of the distance between the second connecting member and another connection point of the wave-guide.

Abstract: An electrical switching element comprising a housing having an elongated base. An electrical coil is wrapped around a yoke and arranged in the housing such that a center axis of the electrical coil is positioned parallel to the elongated base of the housing. An armature having a first switching contact is mounted in a sprung manner and in operative connection with the armature. A first low-profile contact is connected to the first switching contact, and a second low-profile contact is connected to the second switching contact.

Abstract: A circuit breaker mechanism comprises a coil which surrounds a tube in which a magnetic core can move against the urging of a spring. An armature is located adjacent the coil and moves transversely relative to the axis of the coil, with a head portion of the armature being attracted towards a pole piece of the mechanism, while a foot portion of the armature is attracted to the magnetic core. The armature is pivoted to a magnetic frame at a point between the head and foot portions, so that the magnetic force between the head portion and the pole piece is counteracted to some extent by the magnetic force between the foot portion and the magnetic core. This in turn depends on the position of the magnetic core in the tube, and the setting of an adjuster mechanism which spaces the foot portion closer to or further away from the core in use. The adjuster mechanism allows the instantaneous tripping characteristic of the mechanism to be adjusted in use.

Abstract: A superconducting electromagnet apparatus comprises a main coil assembly (1) and a main current supply (5) energising and de-energising the main coil assembly (1), and for persisting the current flow in the main coil assembly (1) when a desired constant current level has been reached, in order to generate a central magnetic field of high homogeneity in a working volume. The apparatus further comprises a B0 shim coil assembly (2) comprising superconducting shim coils connected within a closed loop and arranged to magnetically couple with the main coil assembly (1) and an auxiliary current supply (6) for supplying current to the closed loop, and for persisting the current flow in the closed loop when a desired constant current level has been reached, in order to provide fine adjustment of the central magnetic field within the working volume without significantly degrading the homogeneity of the central magnetic field.

Abstract: The present invention relates to techniques for enlarging an opening, which accommodates a subject, in a superconducting magnet apparatus for use in MRI system, so as to prevent the subject from feeling claustrophobic, and for realizing low magnetic field leakage therefrom, and for reducing the weight thereof, and for realizing a large high magnetic field strength uniform magnetic field region. Static magnetic field generating sources of the superconducting magnet apparatus are constituted by two sets of superconducting coils, the respective sets of which are placed in such a manner as to face each other across a uniform magnetic field generating region. Each of the sets of superconducting coils consists of a main coil for feeding electric current in a specific direction, a bucking coil for feeding electric current in a direction opposite to the direction of the electric current flow passing through the main coil, and a coil for correcting magnetic homogeneity.

Abstract: An electromagnet includes a coil, a movable iron core adapted to move on the center axis of the coil, and a stationary iron core provided so as to cover the upper and lower surfaces and the outer peripheral surface of the coil. A permanent magnet is arranged in a gap surrounded by the movable iron core and the stationary core.

Abstract: An actuator has a first yoke plate, a second yoke plate, magnets, coils, a haptic feel providing member, and a coil fixing member. The first yoke plate and the second yoke plate each assume a plate-like shape having a generally square outline, and are provided approximately parallel with each other. The magnets are fixed to that surface of the first yoke plate which is opposed to the second yoke plate. The coils are provided movably between the magnets and the second yoke and are fixed to the coil fixing member so as to form a unitary body together. Electromagnetic forces that are generated in magnetic fields of the magnets act on the coils, whereby the haptic feel providing member that is supported by the coil fixing member is moved.

Abstract: A magnet system having a magnet coil surrounded by a magnet pot is provided, the magnet coil being electrically connected to contact prongs, an interspace being formed between the outside of the magnet coil and the inside of the magnet pot, in which interspace a free-flowing compound is cast. The magnet coil is surrounded by a thin-walled coil insulating frame on which tubular contact guide elements are integrally molded. The thin-walled coil insulating frame is made of a thermally stable plastic material mixed with mineral fillers.

Abstract: Effect of vibration of a refrigerator on a superconducting coil is reduced to reduce disturbance in an image. A coolant tank for supplying a coolant to coil containers is provided separately from the coil containers, and the refrigerator is placed in the coolant tank, and a coolant circulation passage connects between the coolant tank and the coil containers.

Abstract: Improved Litz track rungs for urban Maglev Inductrack use are provided using an anneal, stainless steel square tube cut to length.

Abstract: A dual transformer design, each transformer having at least a primary winding and a secondary winding disposed on a core means, wherein the core means is circumferentially disposed about an inner housing means, and the whole structure located within an outer housing. The primary winding of one transformer of said pair of transformers is electrically coupled to the primary winding of the other in a manner such as to cause induced eddy currents from one transformer to be of a magnitude and direction so as to substantially cancel the induced eddy currents from the other transformer.

Abstract: A silicon steel core for transformers or choke coils includes at least one silicon steel sheet core which has at least two sets of silicon steel sheets that have respectively a magnetic flux section of a different length such that when two sets of the silicon steel sheet cores are coupled, the magnetic flux sections form at least two gaps of different intervals. Thereby the silicone steel sheet sets of a smaller gap can provide adequate electric induction for the transformers or choke coils while the silicone steel sheet sets of a greater gap can reduce the saturated condition when the transformers or choke coils are in the high load condition.

Abstract: An adjusting device is for a thermal trip element of a switchgear. It includes a bimetallic element that is stationarily fixed on a bimetallic support. The free end of the bimetallic element is spaced apart form a trip lever and increasingly impinges the same in the direction of release was a result of the thermal deformation, the distance being adjustable by bending the bimetallic support. The adjusting device is especially suitable for circuit breakers or the like.