Abstract: Methods and apparatuses for use in tuning reactance are described. Open loop and closed loop control for tuning of reactances are also described. Tunable inductors and/or tunable capacitors may be used in filters, resonant circuits, matching networks, and phase shifters. Ability to control inductance and/or capacitance in a circuit leads to flexibility in operation of the circuit, since the circuit may be tuned to operate under a range of different operating frequencies.

Abstract: A communication system transmits signals having frequencies that lie within a transmission band and receives signals having frequencies that lie within a reception band. The system includes a duplexer and an antenna. The duplexer includes a transmission branch and a reception branch. The transmission branch includes a transmission filter, a transmission phase shifting network and a transmission matching network. The reception branch includes a reception filter, a reception phase shifting network and a reception matching network. The transmission matching network and the reception matching network have predominately constant phase shifts over frequencies within the reception band and within the transmission band, respectively. The antenna is coupled to the transmission matching network and to the reception matching network, and shows a predominantly reactance-only impedance variation over frequencies in the transmission band and over frequencies in the reception band.

Abstract: A circuit (C1-C4) is employed in a TWACS transponder (T) installed in an electric meter (M). The transponder generates inbound signals (IB) transmitted from the location of the electric meter to a central location (R). Firmware (F) within the transponder controls the flow of current for each pulse through the circuit by triggering a semi-conductor device such as a SCR (X1) or TRIAC (X2). The resulting current flow through the inductor for a subsequent pulse, regardless of the pulse's polarity, will be in the opposite direction to that of the previous pulse. The result is to maintain a constant level of magnetization of the inductor core which does not have to be overcome by energy in the subsequent pulse resulting in amplitude of all the pulses imposed on an AC waveform being substantially the same.

Abstract: A tunable inductor includes a main wiring and at least one tuning module. The main wiring is arranged to encircle an inductor area of the tunable inductor. In addition, the tuning module is arranged to couple associated nodes of the main wiring. For example, each tuning module of the at least one tuning module includes a first switch positioned within the inductor area, and further includes at least one auxiliary wiring. When the first switch is turned on, the tuning module couples two nodes of the main wiring, where the at least one auxiliary wiring is arranged to couple the two nodes when the first switch is turned on. In particular, a patterned ground plane is arranged to decrease the energy loss of the tunable inductor, and more particularly, to prevent the tunable inductor from suffering energy loss. The patterned ground plane includes some conductive sections forming a W-like shape.

Abstract: A double tuned circuit includes: a primary tuning circuit connected to an input terminal; and a secondary tuning circuit connected to an output terminal. The primary tuning circuit has a primary capacitor connected between the input terminal and a ground and a primary inductor connected between the input terminal and the ground and formed of a first coupling line having a spiral shape. The secondary tuning circuit has a secondary capacitor connected between the output terminal and the ground and a secondary inductor connected between the output terminal and the ground and formed of a second coupling line having the same spiral shape as the first coupling line, arranged alternately with the first coupling line, and having an M-coupling with the first coupling line.

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 a switch. When the switch is closed, the second inductor couples to the first inductor and the tuned portion has first tuning characteristics. When the switch is open, the second inductor is decoupled from the first inductor and the tuned portion has second tuning characteristics. The tuned portion may include lumped or parasitic capacitance. The tuned portion alternately includes an inductor having a first terminal, a second terminal, an intermediate tap, and a switch that couples between the second terminal and the intermediate tap. When the switch is closed the tuned portion has first tuning characteristics and when the switch is open, the tuned portion has second tuning characteristics.

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 device and a method for contactless transmission of data or power include an impedance which is connected into an LC resonant circuit only in a phasewise manner, in order to match a resonant frequency of the resonant circuit to an excitation frequency. This is realized by measuring a difference between the resonant frequency and the excitation frequency and connecting the impedance into the resonant circuit as a function thereof in a manner controlled by a charging current. In this case the charging current is phase-gating-controlled, and consequently only an effective component of the impedance is connected into the resonant circuit.

Abstract: The magnetic field of an inductor is decreased by the presence of one or more single loop windings positioned in proximity to the inductor. The single loop windings have open circuits that are selectively closed to magnetically couple the single loop windings to the inductor. A switched inductor/varactor tuning circuit is formed by connecting a varactor to the inductor.

Abstract: The oscillator having a tunable resonant circuit has a switch for expanding the tuning range, which is connected in series with two coils jointly determining the oscillation frequency of the resonant circuit. A further coil, which is coupled to the resonant circuit in the region of the switch, is used to supply a switching voltage for the switch. In this arrangement, the other end of this third coil is coupled to a reference potential, with a capacitor, which acts as a short circuit for radio-frequency purposes, decoupling the switching voltage from the reference potential. Since the switching voltage is in this case coupled to an oscillator circuit node which is earthed for radio-frequency purposes, it is of no significance in this case which resistor is used to couple the switching voltage. This means that the resonant circuit is not resistively damped by the connection of the switching voltage.

Abstract: A high-Q precision integrated reversibly trimmable singleband oscillator and tunable multiband oscillator are presented that overcome the problems laser trimming and solid state switches. This is accomplished using micro-electromechanical system (MEMS) technology to integrate an amplifier and its tunable LC network on a common substrate. The LC network can be configured to provide a very narrow bandwidth frequency response which peaks at one or more very specific predetermined frequencies without de-Qing the oscillator.

Abstract: A variable RF inductor network having a plurality of coaxial cables with their respective outer conductors in electrical contact with each other, thereby forming a common outer conductor. This common outer conductor is connected to an RF ground and an RF source. An RF choke is formed between the RF ground and RF source by winding the coaxial cables around a first of a series of inductor cores. The coaxial cables are then wound serially about the remaining succession of inductor cores to form serial, separate inductors. At each separate inductor core, one of the cables is terminated and the inner conductor of the terminated cable is connected to a PIN diode switch for switching the particular inductor out of the network by shorting the common outer conductor across the core. The inner conductors are connected to a biasing means for individually controlling each PIN diode switch to selectively switch particular inductors in and out of the network.

Abstract: The present invention includes a Voltage Controlled Oscillator (VCO) having a resonant circuit capable of being quickly switched between two resonant frequencies in order to generate two different LO frequencies. In a preferred embodiment, the present invention includes a VCO having a dual-frequency resonant circuit attached to the VCO's resonant circuit input leads. The dual-frequency resonant circuit is constructed in a differential architecture in order to create a number "virtual ground" points within the circuit that nearly eliminate any ground currents, and thus minimize the time required to switch the resonant circuit between the two LO frequencies. The switching between two resonant frequencies is achieved by creating a short circuit across certain components within the circuit to eliminate them from the resonant circuit.

Abstract: An integrated, tunable inductance network features a number of fixed inductors fabricated on a common substrate along with a switching network made up of a number of micro-electromechanical (MEM) switches. The switches selectably interconnect the inductors to form an inductance network having a particular inductance value, which can be set with a high degree of precision when the inductors are configured appropriately. The preferred MEM switches introduce a very small amount of resistance, and the inductance network can thus have a high Q. The MEM switches and inductors can be integrated using common processing steps, reducing parasitic capacitance problems associated with wire bonds and prior art switches, increasing reliability, and reducing the space, weight and power requirements of prior art designs.

Abstract: A tuning circuit is formed of inductors connected in series, voltage-controlled variable capacitance means connected in parallel to the inductors, switch means connected in parallel to one of the inductors and capacitance means connected in parallel to another of the inductors, and the resonance frequency of a resonant circuit of the inductor and the capacitance means is set higher than the resonance frequency of the tuning circuit. When the switch means is turned off to change the frequency of the -tuning circuit to the lower frequency band, the frequency variable ratio of the tuning circuit becomes large and when the switch means is turned on to change the frequency to the higher frequency band, such frequency variable ratio becomes small, and the frequency variable width of the lower frequency band can be set almost equal to the frequency variable width of the higher frequency band by adequately selecting the capacitance of the capacitance means.

Abstract: A solid state automatic tuner is used in a plasma processing system for measuring and adjusting a voltage standing wave ratio of the system. The tuner has a switched variable inductor circuit controlled by an automatic control system coupled to an impedance matching circuit. The impedance matching circuit provides an intermediate impedance and matches an output impedance of an RF generator to the varying impedance of a plasma chamber. A variable inductor of the switched variable inductor is constructed as a transformer and allows different values of inductance to be switched in and out of a secondary winding of the transformer. FET switches control pin diodes permitting the different values of inductance to be switched in and out in steps. A VSWR comparator of the control system continuously compares a desired VSWR set point for the system to the current VSWR of the system. A sequence scanner controls the FET switches.

Abstract: A multilayer printed circuit board (100) includes a plurality of layers (101, 102, 104, 106, 108 and 110). Located within intermediate layer (106) is an inductor (200) which is shielded by top layer ground plane (202) and bottom layer ground plane (204). In another embodiment of the present invention, the inductor (200) can have its inductance adjusted by way of a inductance adjustment runner (316, 318) or by an electronic inductance adjustment device (408).

Abstract: Switchable inductors for strong currents are used especially in antenna tuning circuits. The value of the inductance between the terminals of the primary winding of an air-core static transformer is different depending on whether the secondary winding of the transformer is placed in an open circuit or in a short circuit by switching means formed by power semiconductor elements. Application in particular to antenna coupling circuits for VLF stations working by frequency hop transmission with highly selective antennas.

Abstract: A switchable resonator device having a selectable center frequency over a wide radio frequency range comprising a radio frequency signal input and output means, a resonator structure connected between the signal input and output means for respectively receiving and delivering radio frequency input and output signals, the resonator structure using a strip line conductor having a first conductor element with first and second extending portions each providing respective inductance properties, a first switchable means for controllably connecting the first portion of the first conductor element at selected locations along its extension with the second element for varying its inductive properties, a second switchable means for controllably providing a selected capacitance between the second portion of the first conductor element and the second conductor element, and control means providing a control signal to the first and second switchable means for selecting and changing the center frequency of the resonator devi

Abstract: A circuit arrangement which includes a switched inductor comprises a spiral inductor and a MESFET coupled in parallel for switching the spiral inductor in and out of a circuit. The MESFET has at least two gates, at least one of which and at least one section of at least one turn of the spiral inductor, are all mounted adjacent to one another on an active mesa. The switched inductor thus enables parasitic capacitances to be reduced and saves space on the mesa.

Abstract: In a tuner circuit in which a plurality of band signals are received by a single common high frequency amplifier stage, a band switching circuit switches a resonant circuit to .lambda./2 type when the amplifier stage receives the highest band signals and to .lambda./4 type when the amplifier stage receives band signals other than the highest band signals.

Abstract: A circuit arrangement of input stages for a television tuner for the UHF, VHF and hyperband frequency bands in a continuous frequency range having primary bandpass filters for the UHF and VHF bands arranged in parallel, and connected to a signal input aerial (7). The input of the VHF primary bandpass filter is coupled to at least one grounded first inductance (27), series-arranged second and third inductances (29 and 31) between the output and the first inductance (27) and a grounded variable capacitor (33) arranged at the output and a first switch (35) which shunts the second inductance (29) and switches between the BI and the BIII ranges of the VHF band.

Abstract: A double-tuned circuit is provided of the type comprising a primary tuning circuit including first and second resonance coils connected in series and a first switching diode interposed between the connection point of the first and second resonance coils and the ground, and a secondary tuning circuit including third and fourth resonance coils connected in series and inductive-coupled with the first and second resonance coils, respectively, and a second switching diode interposed between the connection point of the third and fourth resonance coils and the ground, wherein band switching is preformed by turning on/off both the first and second switching diodes, which is characterized in that a bias voltage for turning on the first and second switching diodes is supplied to one of the switching diodes and through a conductive wire inductive-coupled with a sintered magnetic material to the other of the switching diodes, whereby an enlargement of the bandwidth and degradation of the flatness of the passband characte

Abstract: A tuner in which a band switching signal corresponding to a channel selected from a plurality of UHF and VHF bands is generated to enable the formation of a suitable resonant circuit for receiving television signals of the selected channel. It includes a varactor diode, a plurality of resonant coils and distribution constant lines which are each grounded at one end. Each of the coils and the line is provided for forming a resonant circuit for tuning one of the bands. A plurality of switching diodes are provided for connecting the other ends of the coils and the line selectively to the other end of the varactor diode. The tuner further includes a device for turning on and off the switching diodes selectively in response to the band switching signal.

Abstract: A band switching circuit of a tuner comprises a tuning circuit, a switching diode connected to the tuning circuit, a pair of band switching terminals coupled across the switching diode. A novel transistor is inserted between one of the band switching terminals and one end of the switching diode with one PN junction of the novel transistor opposing in polarity to the PN junction of the switching diode.

Abstract: A variable inductor usable in a fast tuning RF network comprises a plurality of inductor switching circuits connected in series. Each inductor switching circuit includes an input terminal connected to a discrete inductor and to a PIN diode, and includes an output terminal connected to switches which are in turn connected to the parallel connected discrete inductor and PIN diode. The PIN diode operates in either the forward bias mode for switching out the respective discrete inductor, or in the reverse bias mode for switching in the respective discrete inductor. The PIN diode is forward or reverse biased by MOSFET switches one of which has a parasitic capacitor used to provide a charged rectified reverse bias voltage to the PIN diode to insure reverse bias operation during large voltage changes in the conducted RF signals. The MOSFET switches are controlled by logic signals so that rapid switching by computer or other processor control is possible.

Abstract: A band switching circuit for a tuner for receiving VHF and UHF channels comprises a tuning circuit including a switching diode having an anode and a cathode for band switching, a plurality of resistors connected to the anode and cathode of the switching diode to thereby form a series-connected circuit, and a second diode connected in the series-connected circuit in a direction opposite to that of the switching diode. The switching diode can be forward-biased or reverse-biased for receiving the VHF channels, and can be disconnected from a DC power supply for receiving the UHF channels.

Abstract: The invention relates to a two-circuit resonant bandpass filter for television tuners for switching a first frequency band to a second frequency band. The bandpass filter has a common primary circuit to which two secondary circuits are coupled, a first of the secondary circuits being connected via an electronic switch to the primary circuit which, together with the reactances of the first secondary circuit, short circuits, in the closed condition, the second secondary circuit.

Abstract: A high speed antenna coupler and method for rapidly switching binary weighted values of inductance and capacitance into and out of the circuit between an antenna and a utilization circuit without unacceptably degrading the coupler or slowing the switching action. PIN diodes are utilized as switches and the control wires for the PIN diodes are disposed interiorly of the copper tubing which forms the inductance elements. The control wire for a particular inductor is withdrawn from the interior of that inductor adjacent the mid-point thereof so that the control wire will be at the same RF potential as the inductor being controlled. Two diodes are utilized for each inductor, one connected to each end thereof, so that only half of the normal reverse bias is required for switching purposes. Where a transformer is utilized to couple the antenna to the utilization circuit, the control wires may be disposed interiorly of the copper tubing which forms the winding of the transformer.

Abstract: Herein disclosed is an RF amplifier which is equipped with a high-frequency amplifying element such as a dual gate MOS FET having its first gate fed with a bias voltage and its second gate fed with an AGC voltage, in which a switching diode is fed with a switching voltage thereby to switch the bands, in which the voltage at a voltage dividing point where the switching voltage is divided is used as the bias voltage, and in which the voltage at the dividing point is so raised upon the reception of a high band as to make the effect of the AGC uniform upon the receptions of the low and high bands.

Abstract: A rotary preset tuner comprising a plurality of adjustable memory slugs, a single tuning member capable of being rotated in any direction, a sliding member connected to variable condenser elements and arranged so as to enable reciprocating movement thereof along guide members, and a sliding member reciprocation means for reciprocating the sliding member by rotating the tuning member. Tuning is provided by rotating the tuning member and reciprocating the sliding member to select a desired one of the plurality of adjustable memory slugs, the sliding member being resiliently abutted against the selected memory slug.

Abstract: A bandpass filter is described for filtering a television signal. The filter has a passband which may be selectively centered for filtering signals in one of two channels of the television receiver. The television channel at which the filter passband is centered is selectable by applying a voltage to a control terminal. The filter frequency response for each channel selected may be independently controlled and a linear phase response is realized for the selected channel minimizing distortion.

Abstract: In a VHF-UHF tuner, the signal from the VHF antenna is fed to a resonant circuit comprising a plurality of coils which are selectably shorted out by a channel selection switch to select the various channels. The output of the resonant circuit and the UHF IF signal are fed to a band switch integral with the channel selection switch. The channel selection switch is adapted to short out the coils of the resonant circuit when in the UHF position to attenuate the VHF channel 2 signal component and prevent interference thereof with the UHF IF signal and the production of a beat frequency signal.

Abstract: A digital tuning device for accurate selectable tuning of a resonant circuit. The inductive and capacitive elements of the resonant circuit are connected by a transformer device whose turns ratio is variable in accurate digital increments. Since the reflected reactance is related to the square of the turns ratio and since the resonant frequency varies as the inverse square root of the reactance, the resonant frequency of the circuit is directly related to the turns ratio.

Abstract: In one aspect, the circuit has a first impedance element which preferably is in the form of a tapped inductor with a plurality of taps thereon, and a second impedance element which preferably is in the form of a capacitor. One terminal of the capacitor is connected to a terminal of the inductor, the other terminal of the capacitor is movably connected to a selected one of the taps. The circuit is tuned to a resonant frequency determined by the value of the capacitor and the value of inductance associated with the selected tap. The taps are located on the inductor to cause each resonant frequency to be a substantially fixed percentage greater than the next lower one of the resonant frequencies. In one embodiment, a connector plug is provided, having a first portion with a terminal connected to the capacitor; a second portion with terminals connected to the taps on the inductor; and a third portion matable with the second and third portions.