Abstract: A passive filter device for a capacitor in series with a substantially inductive transmission line of an electric transmission system is disclosed. The passive filter device comprises a double-loop RCL filter in parallel with the series capacitor. At power frequency, the filter device allows the power frequency current to pass through the series capacitor with minimum power losses. At sub-synchronous resonance frequencies, the passive filter device provides bypassing of the series capacitor with maximum selectivity of the RCL filter.

Abstract: Disclosed is a new single-phase passive harmonic filter for one or more nonlinear loads. The filter improves the total system performance by drastically reducing the line side current harmonics generated by nonlinear loads. The filter includes single-phase integrated inductances with an appropriately placed tap across which is connected a tuning capacitor. The combination of the inductance up to the tap position and the tuning capacitor form a series tuned filter configuration while the remainder of the integrated inductance is used for harmonic attenuation. A shunt capacitor is employed for shunting higher order harmonic components. A single-phase passive voltage regulator provides the needed voltage bucking to prevent over voltage at the load terminals of the filter. The filter provides an alternate path for the harmonic currents generated by nonlinear loads.

Abstract: In a trap circuit of the bridged-T type, having a delta RC circuit (RR, C1, C2) and a parallel resonant circuit (L, Cp), the capacitance Cp is constituted by variable capacitance diodes (D1, D2) connected via a resistor (8) to a control voltage (Vtone), and the resistor (RR) of the bridged-T circuit is constituted by a PIN diode whose current is controlled by the same control voltage (Vtone) via a resistor (9).

Abstract: A three port diplex filter circuit with common, low, and high terminals having a frequency response up to 1 GHz comprises a Chebychev-like low pass filter connected between the common and low terminals and a Chebychev-like high pass filter connected between the common and high terminals, wherein each filter section further comprises a series resonant circuit connected between the low and high terminals, respectively, and ground. At lower crossover values, inductors are wound on powdered iron toroidal forms to counteract characteristic self resonance.

Abstract: A high-frequency composite component used for a multi-band system, includes first and second circuits connected in parallel, the first and second circuits having infinite input impedances respectively at first and second frequencies, corresponding to first and second bands. Each of the first and second circuits includes a phase shifter, and a trap circuit connected as a load of the phase shifter. The phase shifter of each of the first and second circuits includes a strip line having a length of .lambda./4, wherein .lambda. is a wavelength corresponding to one of the first and second frequencies. The trap circuit of each of the first and second circuits includes a series resonance circuit, and the trap circuit resonates at one of the first and second frequencies.

Abstract: A diplexer for use in communication of telephony and high-speed data transmission, including television, comprises two filters, each of which is constructed with plural stages in the form of a ladder network, one of the filters being a high-pass filter and the other of the filters being a low-pass filter. The filter components, inductors and capacitors, are located on one or opposed sides of a dielectric substrate. The filter components are arranged to minimize interference between signals traveling in the low-pass filter and the high-pass filter. In the case of a parallel branch of the ladder network in each of the filters, wherein the parallel branch comprises a resonant circuit of inductor and capacitor, the branches of the respective filters are located at opposite parts of the array of the filter components.

Abstract: In an LC-type dielectric filter, an inductor is formed on the uppermost or outermost insulation or dielectric layer and electrically connected at the opposite ends thereof to an upper electrode and a lower electrode which cooperate with a thin film dielectric layer to constitute a capacitor, by means of conductive vias. A method of adjusting a frequency of an LC-type filter is also provided. By the method, an optimum inductance for an inductor is calculated based on a measured capacitance and a desired frequency of the filter, and a pattern of the inductor which is capable of attaining the optimum inductance is selected from a group of predetermined patterns which differ in inductance. The inductor is formed on the outermost dielectric layer in such a manner as to have the selected pattern.

Abstract: There is provided an LC filter in which the leakage of an electromagnetic field to the outside is suppressed. The LC filter 20 includes a laminated element 22. The laminated element 22 includes a multiplicity of dielectric layers 24a-24h. One end of a pattern electrode 34a serving as an inductor of an LC resonator is connected to a capacitor electrode 30a serving as a part of a capacitor of an LC resonator through a via hole formed in the dielectric layers 24d and 24e. The other end of the pattern electrode 34a is connected to one end of a pattern electrode 36a through a via hole formed in the dielectric layer 24f. The other end of the pattern electrode 36a is connected to a ground electrode 32a through a via hole formed in the dielectric layers 24e and 24f. Similarly, one end of a pattern electrode 34b serving as an inductor of another LC resonator is connected to a capacitor electrode 30b serving as a part of a capacitor of an LC resonator through a via hole formed in the dielectric layers 24d and 24e.

Abstract: A band-pass filter device includes a band-pass filter having a characteristic for sufficiently passing signals belonging to a passing frequency band to be passed, a first trap circuit having a Q factor sufficiently higher than that of the BPF and attenuating signals belonging to a frequency band ranging frequencies higher than the passing frequency band, a second trap circuit for attenuating signals belonging to a frequency band ranging frequencies lower than the passing frequency band, a third trap circuit having a Q factor lower than that of the first trap circuit and attenuating an unnecessary component generated in the first trap circuit from the signal, a fourth trap circuit having a Q factor lower than that of the second trap circuit and attenuating an unnecessary component generated in the second trap circuit from the signal.

Abstract: The invention provides a tuned filter of reduced overall length in which two coils (air core inductors) are placed side by side, in mounting locations that are transverse with respect to the longitudinal direction of the filter, instead of in-line or diagonal to each other. The transverse mounting of the coils, depending on the number of poles in the filter, results in a reduction in the overall length of the filter to at least 25% to greater than 50% than can be realized in comparison to conventional in-line filter designs. In addition, the transverse mounting configuration results in an improvement in the electrical performance for both the in band and high frequency responses of the tuned notch filter.

Abstract: The invention relates to a resonator coupling and a radio frequency filter, which comprise a transmission line resonator (106), preferably a helix resonator, having an upper and lower end, a transmission line (108, SL3) for coupling to the resonator, and a tap point (121), at which the transmission line (108, SL3) and the transmission line resonator (106) are in direct contact with each other, whereby the transmission line (106) is divided at the tap point (121) into a lower and upper part, the lower part comprising a first part (SL1) and the upper part comprising a second part (SL2). A coupling element (SL4) is placed at the tap point (121) in parallel with the transmission line resonator (106), coupled (M1) electromagnetically to the transmission line resonator (106), thus improving the stop/pass ratio of the filter.

Abstract: The invention relates to a resonator structure and radio frequency filter in which the resonating frequency of a transmission line resonator can be switched in a stepwise manner between at least three values. The switching is implemented as follows: a regulating element including a switch that has at least three states is arranged in connection with the resonator. The three states of the switch correspond to different values of the specific impedance and, hence, the resonating frequency of the transmission line resonator. The regulating element is in accordance with a known arrangement: it may be e.g. a coupling element formed of a strip line on the surface of a low-loss substrate or ceramic, or a side circuit including a capacitive and inductive element, coupled to the resonator.

Abstract: A radio frequency filter comprising several resonator circuits, such as duplex filter, is provides with a given passband. Signal frequencies generating spurious response, mirror frequencies, etc. can be effectively attenuated so that the filter comprises one more resonator circuit connected as a bandstop circuit. That comprises a transmission line resonator (Res), a series connection of an inductive element (MLIN2) and a capacitance diode (D), one end of the series connection being couples to a coupling point in the transmission line resonator, dividing it into two parts (TLIN1, TLIN2), and the other end being couples to the output connector (1) of the radio frequency filter. In addition, means are provided for carrying the direct voltage (V+) to the cathode of the capacitance diode, whereby the series resonance frequency changes according to the control voltage.

Abstract: A filter circuit having an amplifier stage, an upstream filter and a downstream bandpass filter. The filter includes, inter alia, a rejection circuit tuned to an intermediate frequency and a series circuit, tuned to an image frequency and formed by a capacitor and a .lambda./4 coaxial stub. The inductance formed by the coaxial stub is shared by the series circuit and the rejection circuit.

Abstract: A line current filter for less than 10% total harmonic distortion includes an isolation transformer having two mutually coupled coils connected to an AC power source and a voltage rectifier. A shunt circuit is connected in parallel to one of the mutually coupled coils. The shunt circuit is comprised of a series connected resistor and capacitor. The shunt circuit may also include a second resistor connected in parallel to the capacitor. A second capacitor is connected across the two mutually coupled coils between the isolation transformer and the DC rectifier.

Abstract: Filter equipment is adapted for connection to an ac power network (N) for damping of current harmonics originating from an installation (TR, SR1, SR2), connected to the network, for power transmission by means of high-voltage direct current. The equipment has a three-phase filter set (F) with three filter branches which are each normally connected to a separate phase of the network via first switching members (BO). A spare filter branch (FR) is arranged as a stand-by for the three filter branches of the filter set (F) and is adapted for connection to an optional phase of the network by means of second switching members (BR).

Abstract: A switching arrangement is provided for coupling a transmitting unit to a transmission line. According to the present invention, a transformer is provided, whose secondary winding is a portion of the transmission line and whose primary winding is connected with the transmitting unit and integrated into a parallel resonance circuit, whose resonant frequency is tuned, each time, to the carrier frequency of the transmitted signal. In addition, a tuning unit may be provided for the automatic tuning of the parallel resonance circuit.

Abstract: An advantageous embodiment of the invention is the filter of the receiver branch of the duplex filter in a multi-channel radio transmitter/receiver having reception and transmission bands composed of plural radio-frequency channels. In the first state of the filter, when the radio transmitter/receiver is only receiving radio signals, the width of the pass band of the filter corresponds to said reception band. In the second state, in which the radio transmitter/receiver additionally transmits radio signals, the pass band of the filter is switched by current control to cover only part of the reception band. By constructing the filter in the manner proposed it is possible to use current control in the first resonator in the filter of the receiver branch. Because of its power consumption current control is otherwise unsuitable for use in e.g. the duplex filter of a portable radio-telephone.

Abstract: A resonator 10 includes a first dielectric substrate 12. An earth electrode 14 is formed almost entirely on one main surface of the first dielectric substrate 12. A first pattern electrode 16 and a first drawing electrode 18 are formed on the other main surface of the first dielectric substrate 12. The first pattern electrode 16 and the first drawing electrode 18 are covered with an insulation layer 20. A second pattern electrode 22 and a second drawing electrode 24 are formed on the insulation layer 20. The second pattern electrode 22 and the second drawing electrode 24 are covered with a protecting layer 26. The earth electrode 14 is covered with a protecting layer 28. The earth electrode 14, the first pattern electrode 16 and the second pattern electrode 22 are connected with each other through a terminal electrode 30a. Terminal electrodes 30b and 30c are connected to the earth electrode 14. A drawing terminal electrode 32 is connected to the first drawing electrode 18 and the second drawing electrode 24.

Abstract: A transmission line resonator is disclosed which has a resonance frequency that is electrically controllable by control voltage. A reactive circuit is coupled in parallel between two coupling points on the transmission line resonator. The reactive value of the reactive circuit is changed by the control voltage. The reactive circuit can be inductive or capacitive. The control voltage can switch the reactive circuit in parallel with a part of the transmission line resonator between the coupling points, or can control the capacitance value of a capacitance diode disposed in parallel with a part of the transmission line resonator between the coupling points.

Abstract: A small (about 8 inches long) low pass, high power (4000 watts) electric filter may include a tubular outer conductor separated from an dielectric sleeve by an outer dielectric that may be an air-filled gap. The dielectric sleeve surrounds a series of alternating capacitive elements and inductive elements. Each of the capacitive elements includes an inner conductor, such as a copper slug, that contacts the dielectric sleeve. Each of the inductive elements has a helical wire coil surrounded by a dielectric silicone compound that contacts the dielectric sleeve and the inner conductor. The silicone compound in the inductive elements facilitates heat transfer from the inductive elements and increases capacitive capacity. The air gap between the outer conductor and the dielectric sleeve adds another capacitor. The outer conductor and the dielectric sleeve may touch to improve heat transfer from the filter.

Abstract: A ballast filter in which the ballast can operate at a total harmonic distortion of power line current of less than 10%. Power dissipated by the filter when at a THD of less than 10% is relatively low. The input impedance of the ballast is chosen to be no greater than twice the equivalent filter impedance of a front end filter and no less than the equivalent filter impedance/1.5. The filter includes a transformer having a core which at times operates within the non-linear region of its B-H curve under nominally rated ballast load conditions.

Abstract: A circuit for an intermediate frequency filter combines a variable bandwidth series resonant filter circuit and a parallel resonant filter circuit. A variable output impedance drives the filter and a variable input impedance amplifier buffers the output of the filter. The output impedance of the driver is made to track the input impedance of the output buffer. Changes in the gain of the filter with respect to bandwidth are relatively small. The noise figure of the filter remains low. The circuit is not operated in the non-linear region of the crystal because relatively low drive currents are needed at narrow bandwidths so that the crystal is not overdriven. The LC filter tunes out the stray capacitance from the load of the crystal filter.

Abstract: A wideband bandpass filter has a tank circuit connected between an input and output tapping circuit. The tank circuit contains a variable capacitor and an inductor in parallel. The tank circuit determines a center frequency for the bandpass filter. The input tapping circuit has an input variable impedance, and the output tapping circuit has an output variable impedance. The input and output variable impedances determine the continuously variable bandwidth of the filter.

Abstract: A circuit for reducing the effects of unpredictable changes in power supply and variations in loading on sensitive equipment, e.g. CT scanning system, to reduce inaccurate readings and protect equipment. The circuit utilizes a network of variable reactances controlled either by manual switches or by a microprocessor receiving inputs from a plurality of monitoring locations within the network.

Abstract: A resonator comprises two dielectric substrates. A ground electrode and a U-shaped pattern electrode are formed respectively on the two surfaces of the first dielectric substrate. A take-out electrode is drawn out at a certain distance from one end of the pattern electrode, and is connected to the take-out terminal electrode. A guard electrode is formed opposite to the other end of the pattern electrode. A shield electrode is formed on a second dielectric substrate. The pattern electrode, the ground electrode and the shield electrode are connected by a terminal electrode. In addition, the guard electrode, the ground electrode and the shield electrode are connected by a terminal electrode. A chip-type filter can be obtained by forming a plurality of pattern electrodes on an dielectric substrate, and coupling them electromagnetically.

Abstract: An earth electrode and a spiral pattern electrode are formed on both surfaces of a dielectric plate. One end of the pattern electrode is connected to the earth electrode. The width of the pattern electrode is made narrow in proportion to going from one end toward the other end. An area ratio S2/S1 is 0.15 or more when defining an area of the pattern electrode as S1, and an area of center portion where the pattern electrode is not formed as S2. A take-out electrode is drawn out from the pattern electrode with a distance from the one end of the pattern electrode. A chip type filter is manufactured by forming plural pattern electrodes on the dielectric plate, and coupling the pattern electrodes electromagnetically.

Abstract: A switching device is presented for the transmission of telecommunication signals between a telephone network exchange and at least one subscriber connected thereto, where the exchange is able to transmit metering pulses, in addition to the voice signal. The signals are transmitted as digital signals between the exchange and the subscriber via a two-wire line, Which is connected with the exchange through a hybrid switching unit. To prevent the metering pulses from interfering with the voice signals, a parallel resonant circuit consisting of an inductance and a capacitor is connected to the two-wire system of the hybrid switching unit, and the receiving branch of the hybrid switching unit has an active and a passive filter connected in series. The passive filter is adjusted for the metering pulse frequency, and a filter that is tuned to the passive filter is used as the active filter, which compensates for a decrease in the NF (low frequency) level caused by the passive filter, with a corresponding increase.

Abstract: Coil electrodes having a U-shape and shield electrodes having a plane shape are formed on plural dielectric layers. The coil electrodes are connected via through holes which are formed through the dielectric layers, and a spiral electrode is formed. An earth terminal and an input/output terminal are drawn out from the coil electrode to the end portion of the dielectric layer. The shield electrodes are formed on both of the coil electrodes. The dielectric layers are laminated, and the shield electrode and the earth terminal are connected by an external electrode. An external electrode connected to the input/output terminal is formed. A band-pass filter is made by forming plural spiral electrodes and magnetically coupling the spiral electrodes.

Abstract: Two coil electrode patterns are formed on one surface of a plate containing a dielectric material. These coil electrode patterns are formed in a loop shape, and disposed in a magnetically connected state with each other. Input/output terminal patterns and earth terminal patterns are drawn out from the coil electrode patterns toward edges on different sides of the plate. The input/output terminal pattern and the earth terminal pattern of one coil electrode pattern are disposed at a selected distance from each other so as to provide a predetermined impedance. An earth electrode pattern is formed opposite the coil electrode patterns with the plate between them. Earth terminal patterns are connected to the earth electrode pattern. The earth terminal patterns of the earth electrode pattern are connected to the earth terminal patterns of the coil electrode patterns. A trimming electrode may be formed for adjusting the passing band frequency of the band-pass filter optionally.

Abstract: A tunable filter (100) is provided including a first resonator (110) and a second resonator (120). The bandwidth of the tunable filter is maintained constant by providing purely inductive coupling (114) between the first and the second resonators (110 and 120). The first and the second resonators (110 and 120) include tuning elements (108-109 and 118-119) which are second coupled to each other by means of a capacitor (130) to improve image rejection performance of the tunable filter (100).

Abstract: Two coil electrode patterns are formed on one surface of a plate consisting of a dielectric material. These coil electrode patterns are formed in a loop shape, and are disposed so as to be magnetically coupled with each other. Input/output terminal patterns and earth terminal patterns are drawn out from the coil electrode patterns toward an edge portion of the plate. The input/output terminal pattern and the earth terminal pattern of one coil electrode pattern are disposed at a selected at a distance so as to provide a predetermined impedance. An earth electrode pattern is formed opposite portion of the coil electrode patterns with the plate between them. Earth terminal patterns are formed to the earth electrode pattern. The earth terminal patterns of the earth electrode pattern are connected to the earth terminal patterns of the coil electrode patterns. A trimming electrode may be formed for adjusting the passing band frequency of the band-pass filter optionally.

Abstract: A coil electrode pattern is disposed on one surface of a plate consisting of a dielectric material. The coil electrode pattern is formed in a loop shape. An input/output terminal pattern and an earth terminal pattern are drawn out from the coil electrode pattern toward an end portion of the plate. The input/output terminal pattern and the earth terminal pattern are disposed at a distance from each other so as to provide a predetermined impedance. An earth electrode pattern is formed opposite the dielectric coil electrode pattern with the plate between them. An earth terminal pattern is formed to the earth electrode pattern. The earth terminal pattern of the earth electrode pattern is connected to the earth terminal pattern of the coil electrode pattern. A trimming electrode may be formed for adjusting the resonance frequency of the resonator optionally.

Abstract: An active-type band pass filter achieves a compact structure and a minimum noise figure by setting a coupling Q factor (Q.sub.e1) on an input side of an amplifier, a coupling Q factor (Q.sub.e2) on an output side of the amplifier, and a gain G of the amplifier so that they satisfy the condition that Q.sub.e1 <Q.sub.e2 and 1/Q.sub.e1 =G/Q.sub.e2. By increasing the term with the negative symbol in the equation ##EQU1## the total no-load Q factor (Q.sub.o) is set in the negative region.

Abstract: The high frequency tunable filter includes first and second oscillating circuits tuned by voltage-controlled varicap diodes and coupled together via coupling varicap diodes. The voltage-controlled varicap diodes for the tuning of the oscillating circuits and the coupling varicap diodes are controlled by an identical control voltage to obtain the tuning of the filter to its working frequency and to obtain the critical coupling of the two oscillating circuits. The filter finds particular application in the area of portable radio transceivers.

Abstract: Three coil electrode patterns are formed on one surface of a plate containing of a dielectric material. These coil electrode patterns are formed in loop shape, and are disposed in a magnetically connecting state with respect to each other. An input/output terminal pattern and an earth terminal pattern are drawn out from each of the two coil electrode patterns which are disposed toward the end portions of the plate. The input/output terminal pattern and the earth terminal pattern are disposed at a distance for each other so as to provide a predetermined impedance. An earth electrode pattern is drawn out from the center coil electrode pattern. An earth electrode pattern is formed opposite the coil electrode patterns with the plate between them. Earth terminal patterns are formed to the earth electrode pattern. The earth terminal patterns of the earth electrode pattern are connected to the earth terminal patterns of the coil electrode patterns.

Abstract: The electrical dampening circuit for dampening resonance of a power signal in a power distribution network, comprises a capacitor C, an inductance L connected in parallel to capacitor C, and a resistance R connected in series with capacitor C and inductance L, values of capacitor C and inductance L being calculated so that (2.pi.f).sup.2 LC=1, where f is frequency of the power signal. The value of R is calculated so that 3.sqroot.L/C <R<(2/3) .sqroot.L/C whereby dampening of resonance is obtained.

Abstract: An automatic tracking notch filter system tracks a large-magnitude narrow band signal through frequency effectively eliminating it. A frequency variable notch filter is responsive to a control input at which is applied a small amplitude AC dither signal. The resulting fluctuation in frequency of the notch filter causes corresponding fluctuations in the magnitude of the notch filter output. The output signal is rectified and band pass filtered around the dither frequency before being demodulated with the dither signal to provide a DC error signal indicating the magnitude and direction in frequency of the filter misalignment. The error signal is integrated and input to the control input of the notch filter with the dither signal such that the notch filter tracks the narrow band signal in response to the feedback signal provided at its control input.

Abstract: A circuit for correcting perturbations in a power system signal operating at a system line frequency includes a capacitor for drawing a capacitive current and a first inductor for drawing an inductive current substantially equal in amplitude and substantially one hundred eighty degrees out of phase with the capacitive current. The first inductor is connected in parallel with the capacitor to form a storage module for storing energy therein wherein the storage module is tuned to resonate at the system line frequency and wherein the storage module is connected in parallel across the load. A second inductor connected in series between a power source and the load isolates the power source from the load.

Abstract: An antenna sharing device having a transmission filter connectable between a branch node of an antenna and a transmitter and a reception filter connectable between the branch node and a receiver. At least one of the transmission filter and the reception filter includes: a first parallel resonance circuit having a capacitor and a coil connected in parallel; a second parallel resonance circuit magnetically coupled to the first parallel resonance circuit; and a capacitor serially connected to the first parallel resonance circuit. One of the first and second parallel resonance circuits has a first resonance frequency, the other of the first and second parallel resonance circuits has one of the first resonance frequency and a second resonance frequency, and a combination of the first and second parallel resonance circuits and the capacitor forms an equivalent circuit providing a small insertion impedance at a third resonance frequency.

Abstract: An electrical filter having first and second filter sections with respective sets of electrical filter components. These sets of electrical filter components include primary tuning coils which are arranged parallel to a reference axis. An electrical isolation shield is disposed on a reference plane between the first and second filter sections for electrically isolating the sections from one another, the reference plane being orthogonal to the reference axis. The unique configuration of the filter sections allows for the filter sections to be independently tuned while being physically and electrically isolated from one another. The filter sections are then coupled to one another both physically and electrically subsequent to the tuning operation.

Abstract: A scheme for counteracting subsynchronous resonance in an AC power system that comprises a passive device in combination with a line inductive shunt reactor (L10). The device is connected from the neutral end (N) of the reactor (L10) to ground and comprises a plurality of circuit branches: one of those branches comprises a condenser (C10), another one includes an inductor (L12) in series with at least one tank circuit (C14, L14). The combination of these elements results in circuit paths from the AC line to ground of selected admittance values for at least one selected frequency as well as in a solid grounding of the shunt reactor neutral at synchronous frequency.

Abstract: A filter network adapted to be placed in parallel with a power supply which provides a high impedance to the 60 Hz utility frequency but acts like a short circuit to all higher frequencies. The network comprises a plurality of parallel circuits, each of which comprise a capacitor, an inductor and a resistor in series with a second resistor coupled in parallel with the inductor. Signal levels above 60 Hz in a prototype circuit using seven such parallel circuits with a parallel capacitor coupled thereto shows that above 60 Hz the signal from the power supply is attenuated by 25-30 dB at 1 KHz and that the impedance is substantially resistive beyond 1 KHz.

Abstract: A first filter the group delay of which in the pass band contains a ripple is connected to a second filter so as to cancel the ripple. The second filter has a pass band at least within the pass band of the first filter. The gain of the second filter is reduced gradually from the frequency of the minimum attenuation into the lower and higher frequency regions and the group delay thereof is reduced gradually from the frequency of the minimum attenuation into the lower and higher frequency regions.

Abstract: A thin-film superconducting LC network comprising a dielectric substrate having first and second oppositely disposed surfaces, a first thin-film superconducting conductor on one of the surfaces defining an inductor, second and third thin-film superconducting conductors on said first and second surfaces, respectively, said second and third conductors opposing each other and having at least a portion of the dielectric substrate therebetween to form a capacitor, and thin-film superconducting conductor for interconnecting the inductor and capacitor to form a desired LC network. In one embodiment, the substrate between the second and third conductors have a thickness less than the thickness of the substrate between the first conductor and it oppositely disposed surface. In another embodiment, the inductor is defined by a plurality of closely spaced adjacent turns and a channel is disposed within the substrate between the adjacent turns.

Abstract: A filter network adapted to be placed in parallel with a power supply which provides a high impedance to the 60 Hz utility frequency but acts like a short circuit to all higher frequencies. The network comprises a plurality of parallel circuits, each of which comprise a capacitor, an inductor and a resistor in series with a second resistor coupled in parallel with the inductor. Signal levels above 60 Hz in a prototype circuit using seven such parallel circuits with a parallel capacitor coupled thereto shows that above 60 Hz the signal from the power supply is attenuated by 25-30 dB at 1 KHz and that the impedance is substantially resistive beyond 1 KHz. To maximize the power factor of the circuit comprising the network and consequently the dynamic range of audio equipment coupled thereto, the magnitude of the total capacitance of the network is chosen to be as close as possible to the magnitude of the input inductance of the audio equipment.

Abstract: A circuit for correcting power factor and for reducing ac line current harmonic components in conjunction with bridge-connected capacitive-filtered loads and for providing a source of ac startup current for associated circuitry, for example a switch mode power supply which may form part of the load. The circuit comprises a rectifier bridge, a dual-tuned circuit having a tuned filter in series between an ac line input and the bridge, and a shunt capacitor across the input to the bridge. The tuned filter comprises a parallel connected inductor and capacitor, the shunt capacitor being tuned with the inductor to form a trap filter to reduce third-order and higher harmonic components in the ac line current. The circuit also includes a current source operatively connected to the shunt capacitor for providing a source of ac current immediately upon application of ac power to the ac line input.

Abstract: An air core inductor having mounted thereon a band of material of selected characteristics providing only an electromagnetically coupled resistance that reflects back into the windings of the inductor for filtering applications.

Abstract: A low pass filter circuit for a radiotelephone which filters harmonic, spectral components of a modulated signal generated by the radiotelephone. The filter circuit is comprised of inductors and capacitors wherein each inductor and each capacitor of the filter is comprised of a distributed-element portion and a discrete-element portion. The distributed element portions of each inductor and each capacitor of the filter attenuate higher-frequency, spectral components of a signal applied thereto. The discrete element components of each inductor and each capacitor of the filter attenuate lower-frequency, spectral components of the signal applied thereto.

Abstract: An FM subcarrier receiver of the type useful for detection of a relatively high frequency subcarrier signal transmitted on an FM carrier which includes baseband and relatively high frequency signals is disclosed. It comprises radio frequency circuitry for providing a radio frequency signal having frequency modulated baseband and subcarrier components. High pass filter circuitry receives the output of the radio frequency circuitry. A tuned circuit receives the output of the high pass filter. It comprises a first inductor and a first capacitor tuned substantially to the frequency of the subcarrier which one wishes to detect. A second tuned circuit is tuned to the subcarrier which one wishes to detect. The second tuned circuit comprises a second inductor and a second capacitor. The first and second inductors comprise ferrite cores and are positioned with respect to each other to allow magnetic coupling therebetween.