Abstract: A fixing screw structure for adjusting a fixing procedure used for fixing a panel to a casing, including a screw, an elastomer and a fixing frame. The screw includes a threaded portion and a tapered portion, and passes through the panel, and the threaded portion is screwed on the casing. The elastomer is annular and disposed around the screw, and has a taper hole corresponding to the tapered portion. The fixing frame is a hollow tube, and is fixed on the panel and positioned around the elastomer. When the screw is screwed, the tapered portion abuts the inner wall of the taper hole and the elastomer is expanded outwardly to fitly abut the inner wall of the fixing frame. The instant disclosure transforms the longitudinal screwing force into a transverse expanding force to fix the panel, thereby eliminating the cumulative tolerance of the casing and the panel.

Abstract: A RFID transponder includes a resonant circuit for providing a clock signal at a predetermined clock frequency, a self-calibration stage for calibrating the resonant circuit's current clock frequency towards the predetermined clock frequency. The self-calibration stage is adapted to compare a first clock frequency of the resonant circuit determined during an interrogation period, during which the resonant circuit is excited by an external RF signal, with a second clock frequency determined during a frequency maintenance period, during which the resonant circuit is excited internally through an oscillation maintenance circuit of the RFID transponder and to calibrate the resonant circuit towards the predetermined clock frequency based on the comparison result.

Abstract: The present invention provides an apparatus for enhancing Q factor of an inductor. The apparatus includes a negative resistance generator coupled to the inductor for providing a negative resistance, and a bias circuit coupled to the negative resistance generator for biasing the negative resistance generator.

Abstract: A noise filter array includes filter elements including an LC parallel resonant circuit and an LC series resonant circuit each of which includes a coil and a capacitor provided in proximity in an array and integrally provided with one another. The LC series resonant circuits include ground capacitors having signal-side electrodes. Inductance adjustment conductors are connected to signal-side electrodes of the capacitors defining the respective filter elements, and a ground electrode of the capacitors is commonly arranged so as to oppose the signal-side electrodes.

Abstract: A Radio Frequency (RF) circuit includes an active portion and a tuned portion. The active portion receives an RF signal and that operates upon the RF signal. The tuned portion couples to the active portion and includes a first inductor, a second inductor, and an NMOS transistor. The NMOS transistor has a gate, a drain, a source, and a body. The drain and source operably couple/decouple the second inductor to/from the first inductor. The drain and source are biased at respective operating voltages (greater than ground and less than a first voltage supply) by the active portion and the tuning portion. The body couples to a first voltage supply, via a control circuit or switch in some cases. Applying a second voltage supply (that is greater than the first voltage supply) to the gate turns ON the NMOS transistor.

Abstract: A tuning circuit for a circuit board having an inductor coupling a first and a second trace, the tuning circuit including a first tuning coil having a loop partially extending over the inductor and a second tuning coil having a loop also partially extending over the inductor. The loop of the second tuning coil also partially extends over the loop of the first tuning coil. The circuit is tuned by adjusting the spacing between the loops of the first and second tuning coils and/or adjusting the spacing between the loops and the circuit board.

Abstract: A tuning circuit for a circuit board having an inductor coupling a first and a second trace, the tuning circuit including a first tuning coil having a loop partially extending over the inductor and a second tuning coil having a loop also partially extending over the inductor. The loop of the second tuning coil also partially extends over the loop of the first tuning coil. The circuit is tuned by adjusting the spacing between the loops of the first and second tuning coils and/or adjusting the spacing between the loops and the circuit board.

Abstract: A reactance of a reactance element in a multi-layer circuit board apparatus is trimmed by cutting a portion of the circuit pattern of the reactance element with a laser beam. The reactance element is sandwiched between grounded layers. A coil circuit pattern having at least a hole therein may be provided as the reactance element. A side portion between the edge of the coil circuit pattern and the hole is cut with the laser beam to trim the inductive reactance. Cutting is effected while the circuit is operated and the operating condition such as an oscillation frequency is observed. A plurality of holes may be provided in the coil circuit pattern. The trimming amount of the inductive reactance is determined by the number of the hole subjected to cutting. The holes may have different sizes. The trimming amount is obtained by which one of the hole is subjected to cutting. The distance between the cut circuit pattern is equal to or larger than the thickness of the circuit pattern.

Abstract: A micromechanical variable/tunable inductor is disclosed. The present inductor comprises at least two elements capable of supporting spatial electromagnetic coupling and means for varying a geometrical relationship thereof. Varying the geometrical relationship between such elements varies the inductance of the inductor. In some embodiments, the geometrical relationship that is varied is the spacing between the two elements. The spacing is varied by creating a differential movement between such elements. In further embodiments, the present invention comprises resonant circuits incorporating such variable inductors, and oscillators including such resonant circuits.

Abstract: The invention relates to a lumped-constant resonator construction, and a method for adjusting a lumped-constant resonator construction. The lumped-constant resonator construction comprises at least one, preferably ceramic substrate (4), at least one capacitance means (5), and at least one inductance means (6). The capacitance means and the inductance means (6) are clearly locatable separately but operatively connected. The inductance means (6) comprises a conductive coating (11). In the lumped-constant resonator construction according to the invention, the inductance means (6) which comprises the conductive coating (11) and which is locatable separately from the capacitance means (5) is provided on a preferably bar-like ceramic body (7) mounted on the substrate (4).

Abstract: An improved tuner for a varactor-tuned local oscillator in a radio receiver includes a winding of a pair of magnetically coupled inductors, preferably constructed in the form of a transformer. Preferably, the first and second windings are magnetically coupled with reduced inter-winding capacitance by axially separating the windings on a common core. The second winding is selectively coupled by a switch to a capacitive load in order to change the inductance of the first winding. The tuning range of the resonant circuit formed by the varactor diode set and the first winding is changed when the capacitive load is coupled. The magnetic coupling between the transformer windings provides DC isolation between the oscillator and the switching circuit. Preferably, a tuning actuator has overlapping ranges of movement for selection of a signal within both the AM and FM frequency bands as the intermediate frequencies for the local oscillator are generated.

Abstract: The inductance value of air-core coils are adjusted using automated methods and inexpensive, noncomplicated apparatus. Adjusting tools are provided which displace coil turns in a linear motion with respect to the coil centerline. Specifically, the coil turns can be displaced by sliding perpendicularly to the coil centerline or by rotating a group of coils in order to modify the coil inductance. The adjusting tools used and the method of coil-turn displacement allow the automated method to reincrease the inductance of a coil in the event that displacement causes an over-decrease of inductance.

Abstract: A unitary tuning structure of a UHF tuner includes an inductance loop, an inductance adjustment element attached to a top portion of the inductance loop so as to be foldable with respect to the inductance loop about an axis parallel to the printed circuit board to which the inductance loop is attached and a capacitance adjustment tab attached to a side portion of the inductance loop so as to be foldable with respect to the inductance loop about an axis perpendicular to the printed circuit board. In another form of the unitary tuning structure, a second inductance loop can be attached within the first loop.

Abstract: A frequency domain sensing system is disclosed for sensing the position of a high energy beam of charged particles traveling within a housing which comprises a plurality of sensors positioned in the wall of the housing radially around the axis of the beam. Each of the sensors further comprises a first electrode of predetermined shape received in a bore in the housing to define a fixed capacitance and an inductance structure attached to the electrode to provide an inductance for the sensing means which will provide an LC circuit which will resonate at a predetermined frequency known to exist in the beam of charged particles. The sensors are further provided with tuning apparatus associated with the inductance structure to vary the amount of the inductance to thereby tune the sensors to the predetermined frequency prior to transmission of the signal to signal detection circuitry.

Abstract: A system and method for adjusting the frequency of operation of a radio frequency circuit including an inductive loop having an adjustable exposed inductor portion is provided. The frequency of operation of the circuit is first detected with means for detecting a parameter relating to and representing the frequency of operation. The adjustable inductor portion is associated with a selectively movable actuator device coupled to the frequency detecting means and a source of signals representing a predetermined frequency of operation for the circuit. A control circuit means, preferably a computer, is coupled to the detecting means and to the source of signals to provide an output control signal when the detected frequency of operation bears a predetermined relationship to the predetermined frequency of operation.

Abstract: Tuning elements are provided for use in varying the inductance of the oscillatory circuits of the transmitter and receiver units of garage door actuators operating at ultra-high frequencies. Each oscillatory circuit is a closed loop circuit fabricated on a printed circuit board. The closed loop circuit comprises a pair of printed circuit conductive paths having a fixed capacitor connected across one of the ends thereof and a discrete generally U-shaped wire connected across the other of the ends thereof. The conductive paths and the U-shaped wire comprise the inductor of the oscillatory circuit. By bending the discrete U-shaped wire at its connections with respect to the plane of the printed circuit board, the inductance of the oscillatory circuit in each unit can be adjusted as needed so that they both operate at the same resonant frequency.

Abstract: The tuning system for a high frequency receiver, particularly an AM receiver for vehicles, comprises a tunable input resonance circuit having a variable inductance formed by the signal winding of a controllable inductor. The control winding of the inductor is supplied with a control current. The control winding is simultaneously used as the frequency determinative element of an auxiliary oscillator. A frequency control loop is used to adjust the oscillating frequency of the auxiliary oscillator by adjustment of the control current. The tuning system allows a selective coupling between the tuned antenna input circuit and the rf front end of the receiver.

Abstract: Disclosed is an apparatus for adjusting an inductor that is mounted on a circuit board. The inductor is of the type comprising two extensible sections connected at one respective end to the circuit board and connected at the other respective end by a connecting portion integral to the inductor. The electrical value of the inductor is adjusted by mechanically engaging the connecting portion between first and second push rods and moving the connecting portion so as to simultaneously extend or compress the two extensible sections. The first push rod extends through an opening in the circuit board to apply mechanical force against the connecting portion and the second push rod extends from above the circuit board so as to clamp the connecting portion between the first and second push rods.

Abstract: A tuner for a television receiver comprises a circuit board formed by a slab of dielectric material having conductors located on one side and discrete components mounted on the other so that it may be readily assembled and soldered. Some of the conductors are arranged to form capacitors and distributed parameter inductors. In the UHF portion of the tuner a strip-like conductor and a wider ground conductor are spaced apart in parallel relationship. The length of the gap between the strip-like conductor and the ground conductor is selected to provide inductive reactance in the UHF band. A slot is cut, punched or otherwise formed through the dielectric material in the gap between the strip-like conductor and the ground conductor to increase the Q (the figure of merit inversely related to loss) of the inductor at the upper end of the UHF range. In addition, the slot significantly improves thermal stability of the inductor.

Abstract: The method of and apparatus for changing the inductance of a high power air core coil through the process of selectively shorting out predetermined numbers of turns. The apparatus comprises a conductive belt which is positioned interior the coil whereby the problems of corona discharge from the winding contents are substantially reduced. Since the shorting conductor is a thin film of conductive material attached to a tape, the mass is very low and vibration forces applied to the unit have much less effect in producing interruptions of contact.