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.

Abstract: A harmonic and subharmonic filter is coupled between a high power RF energy source and a non-linear RF load via a matching network, such as a plasma chamber. The filter passes high power RF energy in a band centered on a predetermined radio frequency, i.e., 13.56 MHz, but blocks and attenuates out-of-band energy at frequencies which are multiples of or fractions of the predetermined frequency. The harmonic and subharmonic filter comprises an input terminal, an output terminal, a series LC resonance path connected between the input and output terminals, and tuned to the predetermined radio frequency, a series resistive path formed of first and second resistors, and a parallel LC resonance path between the junction of the two resistors and ground.

Abstract: A parallel connection multi-stage band-pass filter including an input terminal and an output terminal for signals, a plurality of resonators respectively having resonator frequencies different from and close to one another which are electrically connected in parallel to each other between said input and output terminals.

Abstract: A filter system which may be configured either as a stopband (notch) or passband filter having controlled gain and low ripple throughout its stopband or passband. The system includes a filter network which is operative for splitting an input signal spectrum into a pair of complimentary spectrum components and a coupler for proportionately combining these spectrum components in accordance with a prescribed gain factor. The filter network may either comprise a pair of complimentary band reject and band pass filters connected to a common input terminal or a diplexer including identical filters coupled between a splitter and a combiner.

Abstract: A tuned filter having an improved Q is disclosed in which two or more inductors are placed in parallel to increase the net Q relative to a single inductor of the same net inductance and/or two or more capacitors are placed in series to increase the net Q relative to a single capacitor of the same net capacitance to improve the Q of a tuned filter.

Abstract: A saddle coil for multiple tuned response is realized by a segmented sequence of first LC elements each tuned to exhibit a low impedance at .omega..sub.1 and a second set of LC elements, each tuned to exhibit a low impedance at .omega..sub.2, at least some of said first set of LC elements having one of said second LC elements in parallel therewith.

Abstract: A notch filter having increased pass band characteristics is provided by insertion of an inductor between a normally-grounded capacitor and ground, the capacitor being connected to an inductive-capacitive filter network. By this construction, the equivalent capacitor of the high-frequency equivalent circuit is not connected directly to ground, but rather has the inductor interposed between it and ground. This significantly increases the pass band of the circuit.

Abstract: A multi-pole filter for use in radio apparatus includes a plurality of isolated ceramic resonators each having an associated varicap diode network to enable electronic tuning respective of ceramic resonators. The inputs of adjacent ceramic resonators are coupled via a first coupling path and also via a second coupling path, the first coupling path being composed of a fixed capacitance network and the second coupling path being composed of a capacitance network including the varicap diode networks associated with the adjacent resonators. The selective values of the various capacitances forming the first and second coupling paths are such that the overall coupling between the resonators remains substantially constant during the electronic tuning of the resonators by the varicap diode network.

Abstract: An arrangement includes a network for connection between an AC power supply and the input of a DC power supply containing rectifiers and a filter capacitor. The network forms a fourth order, damped lowpass filter that waveshapes the AC input current so as to either reduce or remove the magnitude of harmonics which primarily cause distortion of the input current waveform. In one embodiment, the waveshaping network includes a tapped inductor connected in series with the input of the DC power supply. A series combination of a damping resistor and a first capacitor is connected in parallel with the series inductor. One end of a second capacitor is connected to the tap of the inductor. The waveshaping network increases the power factor and lowers the total harmonic distortion the input of the DC power supply presents to the AC power supply.

Abstract: An arrangement includes a network for connection between an AC power supply and the input of a DC power supply containing rectifiers and a filter capacitor. The network forms a third order, damped low-pass filter that waveshapes the AC input current so as to either reduce or remove the magnitude of harmonics which primarily cause distortion of the input current waveform. In a preferred embodiment, the waveshaping network includes an inductor connected in series with the input of the DC power supply. A series combination of a damping resistor and a first capacitor is connected in parallel with the series inductor. A second capacitor is connected in shunt with the input terminals of the DC power supply. The waveshaping network increases the power factor and lowers the total harmonic distortion the input of the DC power supply presents to the AC power supply.

Abstract: A tuned filter having an improved Q is disclosed in which two or more inductors are placed in parallel to increase the net Q relative to a single inductor of the same net inductance and/or two or more capacitors are placed in series to increase the net Q relative to a single capacitor of the same net capacitance to improve the Q of a tuned filter.

Abstract: A bandpass and/or elimination filter network for electric signals, includes an input circuit (1) which has the capacity to symmetrize and adapt the input impedance, and two branches (B C) and (D E) to which two frequency dependent cells (L C) are introduced. The branches meet at a combination circuit (2) for convergence to the sole output. This network can be used in communications electronics applications.

Abstract: A frequency response equalizer, particularly for wideband networks, whose purpose is to reduce the influence of parasitic capacitances on the frequency behavior, includes the series arrangement of a first coil, a capacitor, a resistor and a second coil, in parallel with a series resistor, in which series arrangement the coils constitute a bifilarly wound transformer. The transformer includes two main inductances and two leakage sub-inductances, in series with the resistor and the capacitor, being arranged in parallel with the series resistor as an active series resonant circuit.

Abstract: In a multi-stage, varactor-tuned bandpass filter utilizing electromagnetic field coupling between successive filter stages, the effective area of a coupling window provided in the RF shielding separating the filter stages is varied as a function of the varactor tune voltage to provide a flat frequency response over the filter frequency range. The bias current through a PIN diode connected across the coupling window is controlled by varactor tune voltage to effectively decrease the window area with increasing filter frequency.

Abstract: A monolithically realizable radio frequency (RF) bias choke implemented as a parallel inductor/capacitor arrangement connected between a DC supply node and an RF circuit bias point.

Abstract: A parallel connection multi-stage band-pass filter including an input terminal and an output terminal for signals, a plurality of resonators respectively having resonator frequencies different from and close to one another which are electrically connected in parallel to each other between said input and output terminals.

Abstract: Dielectric composites are produced by incorporating metallized particles having a high aspect ratio, such as metallized phospholipid tubules, in a polymeric and/or ceramic matrix and curing or sintering in an electric, magnetic, or flow field to align the particles. The resulting composites have extremely anisotropic properties and high dielectric constants. These composites can be used, for example, in EMI shielding and microwave applications.

Abstract: A combination of passive electrical filters and active electrical filters in a series arrangement forming active passive band pass or high pass or low pass or band reject filters. The preferred embodiment includes an amplifier stage to include high input impedance. These filter combinations are free of internal electrical noise.

Abstract: A switching power supply for controlling an output voltage to a constant value with respect to fluctuations in input or in load, wherein are provided a DC power supply; two dividing capacitors connected in series to both ends of the DC power supply; two semiconductor switches connected in series to both ends of the DC power supply; a transformer having a primary winding, one end of which is connected to a connecting point of the two dividing capacitors; and a T type circuit comprising two inductors connected in series between the connecting point of the two semiconductor switches and the other end of the primary winding; and a capacitor connected between the connecting point of the two inductors and the other end of the primary winding. The control characteristics of the switching power supply are improved by reducing the dependency of the output voltage on fluctuations in the load.

Abstract: A notch filter comprises a helical transmission line enclosed in a conductive activity, and a high Q capacitor coupled to form a series-resonant circuit. The capacitor is fabricated from a portion of coaxial cable having an outer conductor forming a first plate of the capacitor and an inner conductor forming the second plate of the capacitor. The notch filter is particularly suited for rejecting terrestrial interference in a C-band tuner at an intermediate frequency of about 400 MHz.

Abstract: An LC filter having electrode layers formed on opposite surfaces of a dielectric substrate. This filter includes a line electrode formed on one surface of the dielectric substrate. The line electrode extends from one electrode layer along outer edges of other electrode layers.

Abstract: A multi-frequency shunt is provided for use between the rails of a railroad track to define the approach distance for a railroad crossing using a constant warning time or motion detection device. The shunt includes a housing with a PC board having rail terminals thereon being mounted in the housing. There are connections from the rail terminals of the PC board, extending outwardly through the housing, to the rails. The PC board includes a plurality of inductive and capacitive elements mounted thereon and connected to header terminals which are mounted on a header board. There are straps for interconnecting the header terminals with the interconnections between the header terminals determining which inductive and capacitive elements are connected between the rails and thus determining the nominal frequency of the shunt.

Abstract: A bandpass filter circuit arrangement in which a pair of parallel-resonant circuits (1, 2) are reactively intercoupled has a pair of signal input terminals (16, 17) connected to one of the resonant circuits (1) and a pair of output terminals (18, 19) connected to the other resonant circuit (2). Tuning of the filter is accomplished by varying the capacitive component of each circuit by varying the output of a tuning voltage source (20). In order to compensate for the deviation from the optimum intercoupling which would otherwise occur with change of tuning frequency the capacitive component of each resonant circuit is formed by two pairs (5, 7 and 6,8, or 9,11 and 10, 12) of capacitors in series, each series-connected pair effectively forming a varaible capacitive voltage divider to the tap on which the reactive intercoupling means (15) is connected. One capacitor (5, 6, 9 or 10) of each pair is variable, and all these are adjusted at the same rate.

Abstract: A filter is provided with a capacitive element 6 arranged in shunt across the input, two series-arranged inductive branches 3 and 4 between which a shunting inductive branch 5 is arranged and a capacitive element 7 arranged in shunt across the output. One of the two series-arranged branches includes, in series from the central point 30, a first inductance 3A and a second inductance 3B connected at a point 31 and a capacitor 8 is added in the branch. The shunting branch includes two inductances 5A and 5B which are arranged in series and are interconnected at a point 32. Two diodes, used as switches S1 and S2, one of which is blocked when the other is conducting, are arranged, one between the point 31 and the extermity of series-arranged inductive branch arranged opposite the central point, and the other between the same point 31 and the point 32.

Abstract: A multicoupler for use in interfacing multiple frequency-agile transceivers to a single antenna. The multicoupler includes a set of high-Q filters and a switching matrix for selectively connecting the transceivers to the filters. The filters have frequency shift capabilities so that a broad frequency range can be covered by a limited number of filter units. The switching matrix is adapted for connecting any one of the transceivers to any one of the filters in accordance with the operative frequencies of the transceivers and filters. The structure of the multicoupler enables it to rapidly track frequency hopping patterns executed by the transceivers while providing good isolation between the transceivers and producing limited amounts of intermodulation distortion.

Abstract: A filter system for removing selected frequencies from AC power provided on at least two phase lines and a neutral line includes a phase-to-phase filter for removing a first selected AC component at a first frequency from the AC power wherein the frequency component has a line-to-phase displacement within first or second ranges. A phase-to-neutral filter is also provided for removing a second selected AC component at a second frequency different from the first frequency from the AC power wherein the second frequency component has a line-to-line phase displacement outside of the first and second ranges.

Abstract: The present invention is for a highpass input circuit for a television receiver having an additional trap at a predetermined frequency, e.g. CB frequencies. A M derived constant K high pass filter having an intermediate pi configured filter section is provided with an additional inductor in the shunt leg of the pi section for resonating with the bridge capacitance of the pi section and forming an additional trap at the predetermined frequency. The additional inductor is physically formed by an electrically conductive path etched on a printed circuit board.

Abstract: This invention relates to a deactivatable tag useable with an electronic article surveillance system and comprised of planar conductive material cut into a pair of inverse, first and second spiral conductors wrapped about each other and positioned for capacitance and inductive coupling. The invention also relates to method of making tags wherein conductors are cut from a planar web of conductive material in a continuous process in a manner that the cutting results in the formation of two spiral conductors without accompanying waste of conductive material, and thereafter positioning the conductors to provide resonant circuits. The conductors of each pair are connected by welding to provide a reliable circuit.

Abstract: Filter equipment for power lines has a double-tuned shunt filter (F1) which has a series resonance circuit (C1, L1) connected in series with a parallel resonance circuit (C2, L2). The capacitor banks of the two resonance circuits are formed so as to have opposite signs on the temperature coefficent of the capacitor capacitance.

Abstract: A filter comprises components arranged in a plurality of compartments which are magnetically shielded from each other. Each compartment includes components for filtering two frequencies wherein these frequencies are separated by an amount such that inductive coupling is substantially prevented. The compartments are combined to increase the attenuation, and any number of compartments may be utilized to filter the desired number of frequencies.

Abstract: A TVRO receiver for receiving frequency-modulated video signals, the receiver comprising a tuner including a superheterodyne circuit having a voltage-controlled oscillator (VCO), means for supplying a controlling input voltage to the VCO, and a mixer for combining incoming 1st IF signals with the output of the VCO to reduce the frequency of the 1st IF signals to a 2nd IF frequency which is sufficiently high to permit the output frequency of the VCO to be above the frequency range of the 1st IF signals, and a linear phase passband filter for passing a single video channel in the 2nd IF output from the mixer, the filter producing an output which is at least about 10 dB down from its peak at both +10 MHz and -10 MHz from the center of the passband of the filter.

Abstract: For carrying out the deactivation at a lower current and with greater reliability, at least one continuous hole (11) which can be made, for example, by means of a needle roll is provided in the insulating layer (1) of a resonance label in the region (10) between two conducting layers (2, 3).

Abstract: A bandpass filter for a CATV converter is of the structure with a low-pass filter section with low-pass filters connected longitudinally in a plurality of stages and a high-pass filter section, and comprises a variable trap circuit including a varactor and an inductor, and another varactor connected to one of the capacitors belonging to the low-pass filter section. Capacitances of these varactors are controlled by a tuning voltage so as to eliminate the various problems which would occur in a double-balance mixer to be connected at a later stage in the CATV converter.

Abstract: This invention relates to a tag useable with an electronic article surveillance system and comprises of planar conductive material cut into a pair of inverse, first and second spiral conductors wrapped about each other and positioned for capacitive and inductive coupling. The invention also relates to method of making tags wherein conductors are cut from a planar web of conductive material in a continuous process in a manner that the cutting results in the formation of two spiral conductors without accompanying waste of conductive material, and thereafter positioning the conductors to provide resonant circuits.

Abstract: A bandpass filter comprises a reactively intercoupled pair of parallel-resonant circuits (1, 2) to one of which a pair of signal input terminals (15, 16) are connected and to the other of which a pair of output terminals (17, 18) are connected. Tuning of the filter is accomplished by varying the capacitive component of each circuit by means of a tuning voltage applied to a further input (19). In order to compensate for the deviation from the optimum intercoupling which would otherwise occur with change of tuning frequency the capacitive component of each resonant circuit comprises at least three capacitors (5, 6, 7 and 8, 9, 10) in series, each set of three capacitors effectively forming a variable capacitive voltage divider. The two junction points of the three capacitors of each set are each connected to the corresponding junction point in the other set by means of a respective bidirectional reactive coupling (13 and 14 respectively).

Abstract: A noise filter connected to power lines includes two coils connected to the power lines in series, respectively, two capacitances connected to one end of the coils, respectively, and at least one resistance for reducing the gain of a resonance frequency of the filter the resistance being connected to the capacitances and grounded.

Abstract: A resonator comprising an equivalent circuit including an LC series circuit having a first capacitance element and inductance elements connected in series to both sides of the first capacitance element, and a second capacitance element connected parallel to the LC series circuit. A plurality of resonators having this construction may be magnetically connected in series to provide a filter, by utilizing the two inductance elements constituting parts of the resonator and without necessitating separate coupling members such as capacitors or coils.

Abstract: A permanent magnet rotor type electrical alternator-SCR power supply having a unique series resonant LC circuit connected to the alternator and resonant close to the lowest expected frequency of the alternator.

Abstract: A marker for use in radio frequency electronic article surveillance systems where the marker contains an inductive-capacitive resonant circuit and is made reversibly deactivatable and reactivatable by the addition of a piece of magnetic material and means, such as a piece of permanently magnetizable material, for biasing the first material to prevent alternating fields induced therein from changing the magnetic state of that material, thereby preventing hysteresis losses from causing a lowering of the Q of the resonant circuit below the point of detection.

Abstract: For reducing the amount of circuitry and losses in double highpasses for filter arrangements in networks with a high voltage level, the two resonance frequencies and Q-factors of the double highpass are tuned so that in a critical harmonic range, at most a harmless slight resonance peak can occur, for which purpose a series capacitor together with a series choke are connected in series with a shunt circuit grounded, in the case of high voltage and ungrounded in the case of medium voltage, of ohmic, inductive and capacitive circuit elements connected to the network.

Abstract: Integrated capacitors provide more than one capacitor on a single dielectric substrate. A dielectric substrate has a conductive backplane on one side and two or more conductive capacitor plates on the opposite side. The integrated capacitors may be mounted on a shield wall which has a through hole so that one capacitor is connected to the shield wall and another forms a coupling capacitor via the hole between two stages on opposite sides of the shield wall.

Abstract: This invention relates to a tag useable with an electronic article surveillance system and comprised of planar conductive material cut into a pair of inverse, first and second spiral conductors wrapped about each other and positioned for capacitive and inductive coupling. The invention also relates to method of making tags wherein conductors are cut from a planar web of conductive material in a continuous process in a manner that the cutting results in the formation of two spiral conductors without accompanying waste of conductive material, and thereafter positioning the conductors to provide resonant circuits.

Abstract: A TVRO receiver for receiving frequency-modulated video signals, the receiver comprising a tuner including a superheterodyne circuit having a voltage-controlled oscillator (VCO), means for supplying a controlling input voltage to the VCO, and a mixer for combining incoming 1st IF signals with the output of the VCO to reduce the frequency of the 1st IF signals to a 2nd IF frequency which is sufficiently high to permit the output frequency of the VCO to be above the frequency range of the 1st IF signals, and a linear phase passband filter for passing a single video channel in the 2nd IF output from the mixer, the filter producing an output which is at least about 10 dB down from its peak at both +10 MHz and -10 MHz from the center of the passband of the filter.

Abstract: Absorption circuits (C.sub.f,L.sub.F) are used for filtering out unwanted harmonic currents in electric lines (R, S, T), particularly for rated power within the range of 1 MVar-1 GVar, for example in the case of high-voltage direct-current transmission systems. So that the absorption circuit holds the virtual capacitance of the filter capacitor circuit (C.sub.f) at its rated value at a tuned frequency even when one or more capacitors (C11, C21, C12, C22) fail, a compensating choke (L) is provided in the cross branch of an "H" circuit of the capacitors. The capacitance of each capacitor (C11 . . . C22) is equal to the total capacitance C of the filter capacitor circuit (C.sub.f). The inductance L of the compensating choke (L) is equal to 1/.omega..sup.2 C, where .omega.=angular frequency of the harmonic. The compensating choke (L) can be designed for 5%-10% of the power of the filter choke (L.sub.F).

Abstract: An electric resonator includes first and second pluralities of conductors which are disposed in side-by-side relationship to form a first layer of alternating first and second conductors. Additional layers of alternating first and second conductors are disposed atop the first layer such that each conductor of one of the pluralities is horizontally and/or vertically adjacent to conductors of the other plurality. The resulting resonator reduces undesirable capacitance between various conductors thereby increasing the quality factor, or Q, of the resonator.

Abstract: Selected interference frequency signals are inserted into the video or RF signal at the transmitter for scrambling purposes, either singly or in pairs. At the receiving end the signals are decoded by use of filters matched to the transmitted signal. The system allows different scrambling for each pay program thereby increasing the security relative to the prior art single frequency system.

Abstract: The present invention provides a track circuit for AC electrified railways, formed by the two rails (R.sub.1,R.sub.2) of a railway section and comprising a transmitter (E) connected to one end of the track circuit for generating therein an alternating signal of given frequency and a receiver (R) connected to the other end for controlling the operation of a track relay (RV). A number of capacitive impedances (Z.sub.1,Z.sub.2, . . . Z.sub.n) with parallel inductance and capacitor (each having a middle point (3) connected to the ground) are connected between the rails (R.sub.1,R.sub.2) while being spaced apart over the whole length of the track circuit with a given pitch (P), depending on the values of the impedances, so that the transmission attenuation of the circuit at the operating frequency is always less than the transmission attenuation of a circuit having the same length formed by a rail with ground return.

Abstract: Circuit arrangement using carrier frequency control voltage on low voltage power lines for radio interference suppression in brightness control devices using the phase gating principle, comprising a radio frequency interference filter including an interference suppression choke coil and wherein a semiconductor switch combined with the interference suppression choke coil is connected in series with the load circuit which includes at least one incandescent lamp and wherein a capacitor is shunted in parallel with the series-connection of the interference suppression choke and the semiconductor component, including a further choke in the load circuit which presents a high impedance to the carrier-frequency control voltage, thereby preventing the loading of the control voltage on the power lines caused by the low impedance of the capacitor at the carrier frequency when the semiconductor component is in the non-conducting state.

Abstract: A quadrature detector circuit for demodulating frequency modulated information is provided that is particularly designed for use in television receive only (TVRO) satellite communication video receivers. The bandwidth restrictions of conventional quadrature detector circuits are eliminated by substituting a simple ferrite bead for the usual parallel capacitor, inductor, resistor combination heretofore required in quadrature detectors. The quadrature detector hereof produces a higher level of video output, improved linearity, and better selectivity, as compared to conventional quadrature detector circuits. Moreover, the quadrature detector hereof reduces circuit complexity, and decreases material costs and production time.

Abstract: An electronic article surveillance system and a marker for use therein, which marker comprises a tuned resonant circuit including inductive and capacitive components formed of a laminate of a dielectric and conductive-multi-turn spirals on opposing surfaces of the dielectric, wherein the capacitive component is formed as a result of distributed capacitance between the opposed spirals, and wherein the circuit thereby resonates at at least two predetermined frequencies which are subsequently received to create an output signal.