Abstract: A high frequency partial transformer hybrid includes a first divided circular conductive element affixed to one side of an insulated substrate and a second split circular conductive element affixed to the other side of the substrate juxtaposed to the first element. Plated-through holes in the substrate interconnect pads on the first and second elements. Connection tabs on the elements are adapted to be connected to conductors on a printed circuit board when the substrate is orthogonally supported in a rectangular recess in the substrate. In a transformer hybrid embodiment, a third continuous circular conductive element is supported on an additional substrate in alignment with and insulated from the second element. The third element also includes connection tabs that are connectable to the conductors on the printed circuit board.

Abstract: Apparatus for reducing intermodulation distortion in a mixer output signal provides for back-to-back serial connected FET transistors joined at gate and source terminals and cancels intermodulation distortion. In one embodiment the apparatus provides first and second FET having their gates tied to one another and their sources tied to one another such that the FETs are connected back-to-back in series and have equal gate-to-source voltages and FET drain-to-source voltage that are equal in magnitude but opposite in sign to the second FET drain-to-source voltage. A control voltage, such as a local oscillator voltage signal is applied between the FET gate terminals and the FET source terminals to switch the conduction state of the serially connected FETs between a conducting state and a non-conducting state.

Abstract: A circuit of low complexity which selects arbitrary channels from a plurality of multichannel input signals and generates from a plurality of individual frequency channels a plurality of output signals whose channel composition can be freely selected, consists of a plurality of bandpass filters (BP1, BP2 . . . BPn) which are tuned to the individual frequency channels and whose input and output are respectively connected to a gate of one of a plurality of circulators (Z11, Z12 . . . Z1n; Z21, Z22 . . . Z2n) connected in a chain. In this case, at least two circulator chains are present (ZK1, ZK2), and a circulator (Z11, Z12 . . . Z1n; Z21, Z22 . . . Z2n) from one of the circulator chains can be optionally switched to the input and output of each bandpass filter (BP1, BP2 . . . BPn).

Abstract: A signal splitter circuit accepts an input signal and conveys the input signal to two output ports. The circuit operates with minimal attenuation, throughout a very wide bandwidth, and also effectively isolates the output ports from each other. The signal from the input port is coupled to an autotransformer, and the ends of the autotransformer are connected to the respective output ports. A bridge load circuit which includes a transformer winding and a load connected in parallel, is inductively coupled to the autotransformer. The bridge load circuit has no connection to the splitter circuit, other than through the inductive coupling. The splitter circuit also includes inductors in series with the output ports and capacitors in parallel with the output ports. The circuit provides a balanced bridge circuit which cancels signals traveling between the output ports, and the inductors and capacitors provide impedance matching between the input port and output ports.

Abstract: A modularly-designed FM vehicle radio for operation in connection with a plurality of antennas is disclosed, where the summing circuit consists of a series connection of the secondary coils of the output transformers of the input stages.

Abstract: A double-balanced wide band RF mixer includes a first bifilar balun transformer coupling a high level source of RF signal to the primary windings of a pair of trifilar balun transformers. The two output windings of each trifilar transformer are connected in series with the drain-source circuits of a pair of FET transistors which are alternately activated by a symmetric local oscillator signal. An IF signal with reduced second order products of the RF signal is developed between the output windings of the two trifilar balun transformers.

Abstract: The present invention involves a connector for inductively coupling to a multi-wire data bus utilizing a magnetic core and associated coil for inducing signals upon the bus and for sensing such signals on the bus. The connector includes a pair of magnetic members disposed on either side of the magnetic core for attenuating common mode energy generated within the connector at about the same frequency as that of the primary signal appearing on the data bus.

Abstract: The invention is comprised of printed circuit boards having printed networks for improving electrical isolation at high frequencies. The invention provides more than 25 dB of isolation in the 1 GHz range. The invention is particularly useful for signal splitting applications. Multiple two way splitters, each made in accordance with the present invention, can be combined to form four way splitters, and so on.

Abstract: A communication system has a two-wire communications path carrying analog transmission and reception signals, and a four-wire communications path including a two-wire transmission path carrying digital transmission signals and a two-wire reception path carrying digital reception signals. A two-wire/four-wire converter for coupling the two-wire communications path to the four-wire communications path includes an analog/digital converter having an input coupled to the two-wire communications path and an output. A digital filter has an adjustable communications function for generating a predetermined terminating impedance for the two-wire transmission path. The digital filter has an input connected to the output of the analog/digital converter and an output connected to the two-wire reception path. An adder has one input connected to the two-wire reception path, another input connected to the two-wire transmission path and an output.

Abstract: A passive impedance matching device incorporates a pair of power splitters, each having a transformer core with a center tapped winding shunted by a resistance having a predetermined value. The power splitter windings have their center taps connected to the input terminals. The arrangement creates a virtual ground and thus avoids the need to create an unbalanced signal. By cascading stages the input signal can be split any number of times. Unused outputs are terminated with their characteristic impedance.

Abstract: A current mode data communication system is disclosed in which the system data bus is formed by an unshielded twisted wire pair (12). Coupled to the data bus by bus couplers (16) and bus-to-stub couplers (80) are current mode data stubs (82), which also are formed by pairs of twisted, unshielded wires (84 and 86). One or more interface-to-stub couplers (88) are inductively coupled to each curretn mode data stub and, in addition, are connected in signal communication with one of the system utilization devices (10). Data signals propagating along the system data bus (12) are coupled to each utilization device (10) via an associated bus coupler (16), bus-to-stub coupler (80), and interface-to-stub coupler (88) without reflecting the signal into the system data bus (12).

Abstract: A low frequency multi-port signal coupler employing hybrid transformer coupling circuitry for intercoupling from a main communication line to output taps. In one embodiment, the coupler has two tap ports interconnected by two core transformers, each having a termination resistor associated therewith. In another embodiment of the invention, there are four tap ports interconnected by three core transformers and a shunted inductor, and having three termination resistors and a split-matching isolation resistor associated with the output taps. An impedance matching resistance is provided at the input and output of the two port embodiment.

Abstract: An RF coupling device is formed on a hybrid printed circuit which avoids discrete capacitors or resistors. The substrate is formed of refractory dielectric sheet, such as alumina or another ceramic. A printed conductor is printed on the front surface of the substrate, and has one or more broadened portions formed on it as capacitor plates. One or more printed resistors are in contact with the printed conductor. A ground pad is printed in a predetermined pattern onto a portion of the reverse surface of the substrate at selected locations. The ground pad has one or more portions that are in registry with the capacitor plates and serve as grounded plates for the capacitors. One or more inductors can be printed onto the substrate in a meander pattern and in contact with the remainder of the printed conductor. The printed circuit receives one or more RF transformers whose leads can be soldered to the printed circuit.

Abstract: A coupler for a balanced two wire data transmission line includes input and output ports as well as a forward coupled port and a reflected coupled port. The coupler is constructed of passive components including transformers and resistors to provide at the forward coupled port a signal proportional to the signal transmitted from a source to a load and provide at the reflected coupled port a signal proportional to the magnitude of the signal reflected from the load due to mismatch.

Abstract: A low frequency multi-port signal coupler employing hybrid transformer coupling circuitry for intercoupling from a main communication line to output taps. In one embodiment, the coupler has two tap ports interconnected by two core transformers, each having a termination resistor associated therewith. In another embodiment of the invention, there are four tap ports interconnected by a single core transformer having a split-matching isolation resistor associated with each output tap, and a pair of termination resistors at the input and output of the primary winding. An impedance matching inductance is provided at the input in both embodiments.

Abstract: In a .pi./2 power divider, particularly a .pi./2 hybrid for the radio-frequency antenna of a nuclear magnetic resonance tomography apparatus, a decoupling circuit having unbalanced-to-ground line transformers is provided. Each branch thereof contains an all pass network consisting unbalanced-to-ground line transformers at the output. A broadband .pi./2 hybrid is obtained particularly with a broadband 3 dB/180.degree. hybrid as the decoupling circuit.

Abstract: A communication controller in a home bus system comprises a single pulse transformer having two secondary windings connected respectively to a coaxial cable and a pair of wires, to which a personal computer, a television receiver, a sensor, etc. are connected. The controller is provided for transmitting a communication packet to the coaxial cable or the pair of wires and the system automatically transmits the communication packet from the pair of wires to the coaxial cable or vice versa.

Abstract: An improved, high frequency, high or low power, broadband quadrature combiner having a significant reduction in weight, and improved electrical performance such as, decreased insertion loss, improved phase linearity, reduced Intermodulation Distortion (IMD) and improved VSWR, as well as improved simplified tuning opportunities. A reduction in the number of transformers used in the prior art quadrature combiner design facilitates weight reduction and independent tuning of a zero and ninety degree phase network. Specific design improvements to the prior art quadrature combiner include: elimination of the input hybrid, scaling of the phase networks to twice its prior art impedance and optimization of values over the frequency range, and the substitution of an output hybrid utilizing a single hybrid transformer in series with an impedance matching transformer.

Abstract: A signal splitter connects a radio frequency signal source to a pair of output loads, e.g., separate receivers, and has an increased high-end frequency response as compared to similar devices. First and second tubular cores are disposed side by side, each with a pair of toroidal windings therein. An input end of the first winding of the first core is coupled to the signal input and the second end of the second winding to ground, respectively, while output ends of the windings in the second core are connected to the output loads. The other ends of the windings of the two cores are respectively connected to one another to form two single-pair twisted connections. These are passed into through holes of a printed circuit board and are soldered or otherwise electrically connected to a printed conductor on the board. This construction reduces stray inductance significantly and also provides better mechanical mounting than previous devices. The two tubular cores could be fused as a single core with two holes.

Abstract: A direction sensitive coupling unit, and method of operation, is disclosed for use in a communication medium to indicate the presence and source direction of transmissions. A directional coupler is provided for receiving information signals from first and second directions along the medium and for providing an attenuated information signal as its output wherein the attenuation to information signals received from the first direction is greater than the attenuation to signals received from the second direction. A voltage sensitive indicating circuit is coupled to the medium and is adapted to respond to the coupler output for providing a digital indication of the presence and source direction of transmissions on the medium.

Abstract: A directional coupler transformer insensitive to data bus termination failures, includes a ferrite toroid core about which first through fourth windings are wound, the first and second windings being for connection in series with each conductor, respectively, of a data bus for sensing or generating data signal current, the third winding being connected in parallel with the data bus conductors for sensing or generating data signal voltage, and a fourth winding inductively coupled to the other three windings for either coupling data signals traveling in one direction from the data bus to a receiving unit, or coupling data signals from a transmitting unit to the data bus for transmission along the data bus in a given direction.

Abstract: A notch filter which utilizes a quadrature coupler with the input signal on one of its four terminals, a first tuned surface acoustic wave device coupled to a second on of the terminals for receiving the input signal at 0.degree. phase shift, a second tuned surface acoustic wave device coupled to a third one of the terminals for receiving the input signal with a 90.degree. phase shift and the fourth terminal being utilized as the output signal terminal.

Abstract: A four-way power splitter/combiner apparatus comprises five unbalanced ports, configured as a common port and four other ports, with power introduced into the common port, over a relative wide frequency band, being substantially equally divided between the four other ports, and vice versa. Each of the first and second ports of each pair of the four other ports has a substantially in-phase signal thereat, with the first in-phase pair of ports having a substantially 180.degree. signal phase difference from the substantially in-phase signals at the other pair of ports. Each of the balun and 2-to-1 transformers of the push-pull 4-port apparatus can be fabricated of a magnetically-decoupled coaxial cable assembly, wherein the cables are all of the same characteristic impedance as the load impedance magnitude at each of the five ports.

Abstract: A switch circuit and assembly for selectively connecting any one of a series of inputs each carrying a number of VHF signals to any one of a series of outputs. Each input is applied to a respective input board and each output to a respective output board, the input boards being arranged in parallel and generally perpendicular to the output boards. Connections are made between any one input board and each output board by respective pairs of interengaging terminals arranged adjacent the board edges. Isolating plates are interleaved with the boards, the plates located between the input boards extending into the spaces between the output boards, and the plates located between the output boards extending into the spaces between the input board, thereby defining a series of four sided isolating structures around each interengaging pair of terminals.

Abstract: A high frequency directional coupler having improved intermodulation distortion performance is disclosed. The coupler includes input, output, reflected, and incident ports, and current and voltage transformers. The current transformer includes at least one primary winding connected between the inlet and outlet ports and at least one secondary winding coupled with the primary winding and connected between the reflected port and ground. The voltage transformer includes a plurality of series-connected primary windings connected between the reflected and incident ports, and a plurality of series-connected secondary windings coupled with said voltage transformer primary windings, respectively, and connected between the input port and ground. Shunt capacitors connected with the input, output, reflected and incident ports increase the bandwidth of the coupler.

Abstract: A direct current magnetized hybrid transformer in a telephone line repeater has both its primary windings magnetically coupled to two pairs of secondary windings, one pair creating the four-wire path in the repeater and the second pair being connected to a balance impedance. The primary windings are each divided into two parts with a like number of turns. The feeding voltage source included in the repeater is connected between the connection points common for the winding parts.

Abstract: A duplexer is provided in which a transmit input signal is fed in parallel through two autotransformers to a pair of portal loops for establishing an interrogation field. Significantly lower voltage response signals returning via the autotransformers are applied in push-push relationship to the primary of one transformer for producing a difference signal output, and in parallel to a second transformer primary for producing a sum signal output. Back-to-back diodes across the secondary windings of the sum and difference output transformers limit the volt drop across the respective primaries for the relatively higher voltage transmit input signal. The response signal, however, is below the threshold of the diodes and, consequently, the diodes do not attenuate such signal.

Abstract: A directional coupler with a first and second transformer, having their primary windings connected in series, provides a sample of the current flow through the series connected primary windings. A third transformer provides a voltage sample of the voltage that results from the current flow through the primary windings of the first and second transformers. The voltage sample and the current sample are vectorially combined by a vector adder to obtain a first signal that is representative of the reflected power components of the current and voltage samples and also to provide a second signal that is representative of the forward power components of the current and voltage samples.

Abstract: A directional coupler for sampling energy traversing a CATV system of the type wherein wide band television signals are extracted from a coaxial transmission line situated at points located at varying distances from the line amplifier. The coupler includes a voltage sensing transformer in shunt with the center and outer conductors of the cable and a current sensing transformer in series with the center conductor. The transformers are wound to provide the coupler with a relatively low tap value. Windings in the shunt transformer are used to internally boost the impedance at the input to the series transformer to maximize return losses and directivity.

Abstract: In branching equipment for CATV systems, including a distributing transformer consisting of a tapped winding, ends of which are connected to a pair of output terminals whereby a television signal applied to the tap is distributed to the output terminals with a current level ratio determined by the ratio of the number of turns in the winding portion on one side of the tap to that in the winding portion on the other side of the tap, an electric power absorbing resistor is connected between the tap and one of the output terminals so as to reduce the interaction of undesired signals between the output terminals.

Abstract: A high frequency transformer for a wide range of frequencies and of the kind comprising a winding means attached on a core means, the winding means consisting of two parallel conductors isolated from each other, of which conductors one constitutes a primary winding, and the winding formed of the two conductors connected in series constitutes a secondary winding in a transformer coupled by economy coupling with a transforming ratio of 1:2. The conductors are wound on two parallel cores of soft magnetic materials spaced apart and connected by yokes at both ends. The winding pattern between cores lies in figure 8 patterns with opposite coils of the 8 patterns on each of the two cores.

Abstract: The hybrid includes a control circuit which automatically matches the impedance of the balancing network to the input impedance of the two-wire line connected to the hybrid. For control, rectified voltages present on the two-wire side and across the balancing network are averaged over time and the mean time values are compared.