Abstract: A variable attenuator includes a plurality of circuit cells, each containing a variable resistance shunt element, cascaded to form an artificial transmission line with distributed loss represented by the variable resistance shunt element. Parameters of the transmission line are chosen in a manner to establish a characteristic impedance that is substantially independent of the shunt resistance value and to provide low insertion reflection coefficients for all attenuation values.

Abstract: An attenuator for use in an integrated circuit window comparator circuit provides voltage division across an input voltage divider including a large number of identical thin film resistor segments combined in various series and parallel arrangements so that resistive voltage division of the input signal is in the same ratio as capacitive voltage division of the input signal by parasitic capacitances of the resistors.

Abstract: An electric noise absorber, comprising divided magnetic substances made of ferrite, a holding member for holding the magnetic substances at its holding projections, and engaging members formed in the magnetic substances which engage with the holding projections. The electric noise absorber is attached to and detached from an electric cable easily without removing the electric cable and is composed of a minimum number of units.

Abstract: An electric noise absorber, comprising divided magnetic substances made of ferrite, a holding member made of elastic material and fixtures for being connected to each other or fixed to a component of an electronic device, and engaging grooves formed on the outer surfaces of the magnetic substances for engaging with the holding member, is attached to and detached from an electric cable easily without removing the electric cable, and is composed of a minimum number of units.

Abstract: An attenuating circuit including a reference signal path that is attenuated by an amount which is related to the attenuation in an attenuation signal path for the purpose of improving attenuation accuracy.

Abstract: A variable attenuation device intended to be inserted between a transmitter circuit having a certain internal impedance and a load circuit; it composed of at least on parallel attenuation branch made up from a variable resistance component (in particular a p-i-n diode) and a bias circuit to vary the resistance of the component as a function of an attenuation control variable. The parallel attenuation branch has a limiting component which is connected in series with the variable resistance component and whose value ensures the matching of the internal impedance of the transmitter circuit.

Abstract: The present disclosure provides a variable attenuator for attenuating alternating signals, preferably, in a frequency band extending from approximately 10 Hz to 30 MHz. The invention utilizes a junction field-effect transistor (JFET) as a variable impedance. The low drain-to-source capacitance exhibited by the JFET allows it to be modeled as a variable resistor or potentiometer. Further, the low drain-to-source capacitance of the JFET improves the bandwidth of the attenuator. A remote DC control signal defines the resistance provided by the JFET. A feedback loop, responsive to the resistance of the JFET and the remote control signal, controls the resistance provided by the JFET in a linear manner. The DC control signal is low-pass filtered at the feedback loop to reduce any high frequency noise acquired during transmission.

Abstract: The requirements of extreme miniaturization, remote operation, wide bandwidth, good reproducibility in high quantities, low cost and low insertion loss are met with an incrementally adjustable distributed network arrangement in the general configuration of a distributed amplifier. The arrangement comprises delay elements (Z.sub.Dm, Z.sub.Gm) and a plurality of controlled sources (T.sub.n-2, T.sub.n-1, T.sub.ni VCCS), a signal input (E) and a signal output (A). The controlled sources (T.sub.n-2, T.sub.n-1, T.sub.ni VCCS) may be selectively turned on and off. Dual gate FETs (T.sub.1, . . . T.sub.n) are employed as controlled sources, whose first gate (G.sub.1) is connected to the input signal voltage through delay elements (Z.sub.Gm) and whose second gate (G.sub.2) is maintained at suitable dc voltages for turning the respective FETs on and off.

Abstract: An attenuator circuit is provided which comprises an input node, a first resistor connected at one terminal to a reference potential, a second resistor connected to the other terminal of the first resistor, a first output node which is a connection node of the first resistor and the second resistor, a third resistor connected in parallel with the series circuit of the first and second resistors and being of such a type that a resultant resistive value of the first, second and third resistors is equal to a resistive value of the first resistor, a fourth resistor connected at one terminal to a connection node of the second and third resistors and having a resistive value substantially equal to that of the second resistor, and at least one combination resistor of a ladder configuration connected between the other terminal of the fourth resistor and the input node and having a third output node as a junction of its series circuit portion.

Abstract: A variable attenuator having first and second branch circuits configured in bridged T, T or PI topologies, each of the branch circuits having at least one voltage variable FET resistor. The voltage variable FET resistor includes a FET network comprising a plurality of FET segments each of which have a predetermined gate width and a voltage divider network including a plurality of fixed resistors coupled to the gates of the plurality of FET segments for providing a different predetermined gate voltage to each of the FET segments. The gate width of each of the FET segments and the resistance of each of the fixed resistors is chosen to provide a predetermined relationship between the control voltage and the channel resistance of the voltage variable FET resistor, to thereby provide a preselected relationship between the control voltage applied to the first branch circuit and the attenuation ratio of the attenuator.

Abstract: A combined electrical and optical channel for use in an oscilloscope is provided in which the vertical deflection factor is set by a single input attenutation selector switch. The electical input is passed through an attenuator. The optical input is passed through an input transimpedance amplifier having at least two gain modes and an attenuator. The output from the input attenuation selector switch is encoded to form a digital output. The attenuators for the electrical channel are driven directly by the input attenuation selector switch or by the digital output corresponding to the setting of the input attenuation selector switch. The digital output is also decoded by a logic block to generate a gain mode logic signal to switch the gain modes of the input transimpedance amplifier.

Abstract: A variable attenuator comprises a plurality of attenuator stages connected in series along a transmission line signal path. Each attenuator stage comprises a resstive pi-section attenuating pad which may be selectively inserted into the signal path to increase attenuation along the path. Each series element of the pad is selectively inserted or removed from the signal path by opening or closing a parallel connected switching device, while each shunt element of the pad is selectively connected to or disconnected from ground by closing or opening a corresponding series connected switching device. The switching devices each comprise an NPN bipolar transistor and a PNP bipolar transistor, the emitter of each transistor being coupled to the emitter of the other and the collector or each transistor being connected to the collector of the other, to provide a low impedance AC signal path from collector to emitter when the transistors are active.

Abstract: A radio frequency power and voltage modification arrangement (13) including first and second power channels (28 and 29) both electrically connected between first and second hybrid elements (15 and 16), power in said first and second hybrid elements (15, 16) being subject to respective controllable, oppositely signed phase shifts applied to said respective channels (15, 16), for modifying the power output from the arrangement (13) as a function of the cosine of the applied phase modification, without any phase modification between input and output power and voltage.

Abstract: A ferrite toroid retainer 10 provides an apparatus for retaining ferrite toroids 1 on an electrical cable 2 to prevent chafing of the cable's insulation. The device is constructed from an elastomer material. Ferrite toroid retainer 10 is constructed from a toroidal sleeve 11 having an inside diameter B equal to that of the outside diameter A of electrical cable 2. The outside diameter C of ferrite toroid retainer 10 is equal to that of the inside diameter F of ferrite toroid 1. A retaining ridge 12 is attached around the circumference of one end of toroidal sleeve 11 and has a tapered leading edge 13. Attached around the circumference of the opposite end of toroidal sleeve 11 is a non-tapered retaining ridge 15. Perpendicular edges 14 prevent ferrite toroids 1 from sliding off of toroidal sleeve 11.

Abstract: A linear microwave attenuator has an absorbing element which is selectively shaped to provide reduced capacitive coupling and increased attenuation by segmenting the absorber into at least two members. The selective shaping reduces both the surface area and mass of the absorber while maximizing the attenuation of possible from the absorber. In this way, reduced size, linear performance, and increased attenuation over those of the prior art are provided by the present invention.

Abstract: At least two attenuator banks are intercoupled in a cascaded arrangement, wherein the signal across each subsequent attenuator bank comprises a differential signal representing a selected attenuation (or voltage) step of the preceding attenuator bank. In this way monotonic attenuator operation is assured.

Abstract: A complex weighting device contains parallel all-pass networks selectively feeding a pair of differential amplifiers, so as to produce a set of mutually orthogonal vector outputs. These outputs are coupled to an attenuator network comprised of dual gate field effect transistors for controllably attenuating the vector outputs of the differential amplifiers. The attenuated vectors are selectively combined to realize a prescribed degree of phase shift from 0.degree. to 360.degree. through the complex weight.

Abstract: The filter comprises a series branch formed by an inductance coil (L) in parallel with a resistor (R1) and a parallel branch formed by a capacitor (C) in series with a resistor (Rc). For frequencies such that Rc>>1/.omega.C and R1<<.omega.L, the ratio between the output and input powers of the filter has a predetermined maximum value strictly lower than 1 and independent of the load impedance.

Abstract: A programmable attenuator includes a plurality of field effect transistors (FETS) arranged together to provide an attenuation network. Each one of the FETS has a plurality of cell portions, each cell portion having drain, gate and source regions, the source and drain regions of the cell portions being connected in parallel. A first selected portion of the gate regions of each one of said FETS is connected to a gate electrode. A second selected remaining portion of the gate regions of each one of the FETS has the gate regions thereof physically isolated from the gate electrode. A signal fed to the gate electrode of each FET is distributed to the connected gate regions of each field effect transistor. In response to such signal, the total drain-source resistance of such FET is changed between a predetermined low value and a predetermined high value, with the resistance of the predetermined high value being determined, in part, by the number of such isolated gate regions.

Abstract: A microwave absorber composed of dense silicon carbide having an electrical resistivity of one ohm-centimeter or more. In an electron linear accelerator, it is necessary to provide a microwave absorber to absorb excess energy used to accelerate electrons and discharge this excess energy in the form of heat in order for the accelerator to operate safely. The important characteristics are high-frequency wave absorption, good heat resistance, good thermal conductivity, and stability in a vacuum. The invention meets these requirements with a microwave absorber composed of dense silicon carbide. In an electron linear accelerator the absorber is attached to the end portion of an accelerator guide or a branch portion of a power divider to absorb unnecessary wave energy. Such a microwave absorber is found to have characteristics rendering it highly suitable for this application as well as others.

Abstract: A Detector Log Video Amplifier (DLVA) comprising a first RF detector for detecting the power levels of received RF signals having power levels within a first range (e.g., -40 dBm to -20 dBm) and producing corresponding first video frequency signals having amplitudes representative thereof, from which are produced output signals having amplitudes logarithmically proportional to such received signals. A second RF detector detects the power levels of received RF signals having power levels within a second range (e.g., -20 dBm to +20 dBm) and produces corresponding second video frequency signals having amplitudes representative thereof, from which are produced output signals having amplitudes logarithmically proportional to such received signals. A control signal is produced from the second video frequency signals, the control signal having a level in accordance with the power levels of received RF signals. Received RF signals having power levels equal to or exceeding a first level (e.g.

Abstract: A tap device for use in broadband communications systems includes a circuit board mounted on a cover plate assembly which is removably connected to a base housing. The circuit board includes an RF signal coupling element and an RF signal splitting element. The output of the RF signal coupling element and the input to the RF signal splitting element are each connected to a separate female receptacle positioned on the circuit board. The female receptacles are designed to receive an intermediate circuit which, when inserted into the female receptacles, is electrically connected between the RF signal coupling element output and the RF signal splitting element input. The intermediate circuit may consist of a short circuit feedthrough, or a plug-in fixed or variable degree attenuator.

Abstract: A controllable switch matrix module is disclosed for bidirectional transmission of signals between multiple ports in a single module, where the attenuation characteristics are dynamically alterable. The invention uses pin diodes both for isolation and for switching, and achieves its high isolation in part by completely enclosing each of the attenuation functions within separate compartments, enclosing the connections between compartments for isolation between functions, and supplying control signals to the pin diodes using feedthrough connections designed in such a way as to prevent the emission of RF signals via the feedthrough devices. Only two bits are required to define any one of four attenuation levels between any two ports.

Abstract: A monolithic FET bridge attenuator contains four single gate FETs, the source-drain path of each of which forms a respective arm of the bridge. The attenuation control electrodes (gates) of the FETs in opposite arms of the bridge are connected to a common control voltage. A first pair of diagonally opposing nodes of the bridge are coupled to receive respective input signals that differ in phase by 180.degree.. A second pair of diagonally opposing nodes of the bridge disposed between the first pair of nodes provide a pair of output signals differing in phase by 180.degree.. In effect, each FET has the electrical behavior of a parallel RC circuit, the resistive component of which is controlled by the gate voltage.

Abstract: A novel signal scaling MESFET of a segmented dual gate design is disclosed. The MESFET, which is monolithically integrated on a semi-insulating substrate capable of localized surface modification to form active semiconductor regions using MMIC (monolithic microwave integrated circuit) techniques, has a small AC signal transfer which is adjustable in selected discrete steps. For operation in the gigahertz range, the substrate is preferably of gallium arsenide.In applying the MMIC technique, the MESFET, including segment electrodes and segment interconnections, and the electrical connections, signal paths, and passive components connected to the MESFET are formed on the substrate and defined by a photolithographic process. The technique permits reproducable feature definition and very compact minimum reactance segment interconnections, reducing deleterious parasitics and facilitating virtual unitary MESFET operation to very high frequencies.

Abstract: The present invention relates to an attenuator for reducing noise and distortion, preferably in the audio frequency range. Briefly stated, the present invention is comprised of two wedge shapes in one block with two axially opposing leads connected to the wedge shape midway along the line formed by the intersection of two adjacent sides. The leads are preferably bent at 90.degree. and connected to attenuator conductive strips contained on a circuit board. The attenuator conductive strips on the circuit board are preferably at 90.degree. with respect to parallel conductive strips connected to a speaker or the like. The entire attenuator structure is preferably covered with an insulative or dielectric material.

Abstract: An attenuation bead is disclosed with a tube (1) made of ferrite suitable for use as a chip component. The attenuation bead is equipped with frontal contact elements (2) which are electrically corrected with one another by conductor elements (4) in the interior of the tube. The operating range of interference suppression for the attenuation beads is in the short-wave and ultra short-wave frequency bands.

Abstract: A low noise, high thermal stability attenuator of the integratable type is disclosed. The attenuator comprises a fixed network of resistive elements, having a plurality of outputs each at a different attenuation level, and a switched amplifier receiving at its input such different attenuation outputs, as well as a control signal which specifies which of the amplifier inputs is to be output. Advantageously, this attenuator may be implemented in several stages, each having different attenuation ranges or steps.

Abstract: A dual gate MESFET attenuator circuit provides substantial range of attenuation without phase shift through a cascaded arrangement of a pair of dual gate MESFETs and the incorporation of a feed forward resistor. By cascading the two transistors together, the attenuation vector characteristics are effectively rotated 180.degree. or shifted to the third and fourth quadrants of the (real/imaginary) vector plane. The resulting phase shift between the minimum attenuation vector and the maximum attenuation vector is compensated by the insertion of a pure resistance component in a feed forward fashion between the input and output terminals of the cascaded dual MESFET pair. The value of the inserted resistor is chosen so as to effectively make both the maximum attenuation vector and the minimum attenuation vector cophasal, thereby providing a constant phase shift through the attenuator over a substantial range of attenuation.

Abstract: A signal input circuit composed of a control member, such as a PIN diode, for controllable attenuation of an input signal, and reactances for selection of the input signal, wherein the signal frequency current is regulated by the control member such that the operating power required by the input circuit remains constant to the greatest possible degree in spite of the regulation.

Abstract: A switched attenuator circuit providing three selectable voltage-divider ratios including one which passes substantially 100 percent of the input signal. The circuit places constant load resistance on its source in all positions when driving a high-resistance load. The circuit is inexpensive to construct, comprising three attenuation resistors, two input resistance compensating resistors, and two single-pole double-throw switching elements for changing the series/parallel configuration of the attenuation resistors and switching the compensating resistors into the circuit. The circuit places all parasitic capacitance associated with the switches on the input side of the circuit, thereby providing uniformly low output capacitance for all voltage-divider ratios.

Abstract: An attenuator device is disclosed defined by an inner member having an outer cylindrical surface and a coaxial and relatively rotatable outer member having an inner cylindrical surface. Longitudinally extending grooves are defined in the respective surface of each member. Attenuating structure is disposed in the longitudinal length of the grooves of one of the members while bowed leaf springs are disposed in the longitudinal length of the grooves of the other member. The bowed leaf springs extend from the grooves of the other member to engage the grooves and attenuating structure of the one member to thus provide both detenting and grounding for the attenuator device.

Abstract: A digital controlled volume attenuator includes a plurality of resistors connected in series between a signal input terminal and a reference potential point and a plurality of electronic switches having one ends respectively connected to the connection points among resistors and the other ends connected in common. One of signals at the respective connection points among resistors is selected by making either one of the switches conductive to control the volume. A muting circuit is provided between a signal output terminal and the common connection point of the switches to prevent the switching noise generated by the switches from being supplied to the signal output terminal.

Abstract: An RF signal variable attenuation circuit is disclosed having an input terminal for inputting RF signals, an output terminal for outputing attenuated signals, a transmission line connected between the input terminal and the output terminal, first and second PIN diodes inserted in the transmission line in series, a power supply source for supplying a voltage to the first and second PIN diodes, and a control circuit for controlling the conduction of the first and second PIN diodes according to the voltage supplied from the power supply source.

Abstract: A multi-path, ladder-type variable step RF signal attenuator is provided. The ladder network is comprised of a number of asymmetric power splitting elements and PI-pad resistor attenuator elements. The high-speed switching and long life characteristics of PIN diodes are utilized to switch resistive attenuator elements into or out of the ladder network to provide selectable values of signal attenuation.

Abstract: A circuit which attenuates an RF signal in response to a voltage level of a control signal is disclosed. A first PIN diode resides in series with an RF signal path, and a second PIN diode shunts the RF signal path to ground. A first differential amplifier responsive to the control signal drives the first PIN diode, and a second differential amplifier responsive to the control signal drives the second PIN diode. Gain and maximum current output for each of the amplifiers are independently controlled. Additionally, separate reference voltage sources may apply to one input of each of the differential amplifiers.

Abstract: The simulation of a two-wire rheostat is accomplished by an analog output circuit whose value is digitally controlled. It comprises a four-quadrant multiplying digital to analog converter (MDAC) and a current booster including active elements in the feedback loop of an amplifier. The digital rheostat acts as a variable resistance whose value is controlled by a digital controller and can accommodate either AC or DC excitations. The unit forms a negative feedback loop containing only solid-state devices and relies on fixed resistors for accuracy.

Abstract: A soft digital limiter (2) for limiting an analog input signal (1) from a maximum expected range (61) to a useful range (60). The number (m) of desired levels of resolution in the limiter (2) is preselected to be any power of two. An analog-to-digital converter (9) converts the input analog signal (1) to a digital representation (20). The converter (9) has its input voltage rating matched to the maximum expected range (61) and its output resolution matched to the preselected degree (m) of resolution. In the preferred two's complement numbering system, the condition for the input signal (1) falling within the useful range (60) is that the most significant p+1 bits of the digital representation (20) are all identical, where p is the number of bits required by the converter (9) to delineate that portion of the maximum expected range (61) outside of the useful range (60). A network of comparators (e.g., 38, 39) implements this condition.

Abstract: An analog switch circuit comprises a first transfer gate (20) and a second transfer gate (23). The first transfer gate comprise first P-type and N-type field-effect transistors (21) and (22) having first electrodes thereof commonly connected through an output terminal (5) to a load (6) and second electrodes thereof commonly connected through an input terminal (4) to an input signal source (7) of an impedance lower than that of the load. The second transfer gate comprises second P-type and N-type field-effect transistors (24) and (25) of a gate size smaller than that of the respective transistors constituting the first transfer gate having the first and second electrodes connected in parallel with the first and second electrodes of the first P-type and N-type transistors, respectively.

Abstract: An attenuator introduces a known attenuation into telephone circuitry at connecting block terminals of incoming and outgoing, tip and ring lines when clipped thereto. The attenuator is particularly suited for attachment to an insulation displacement terminating block, known as a 66 type block, for telephone wire circuits or pairs. An attenuation network in the form of a balanced square pad is mounted on a substrate to form a printed circuit board and resistance assembly. Electrical contact means include four electrical contacts that have tail portions connected to the attenuation network and clip portions that grip the connecting block terminals of the incoming and outgoing, tip and ring lines. The printed circuit board and resistance assembly and the electrical contact means are received within a protective, insulating cover and retained therein by potting material. The attenuation rating or loss for the attenuator is marked on the top surface of the cover.

Abstract: An improved phase shift network is disclosed which is applicable to broadband systems, particularly in connection with feedforward power amplifier systems. The phase shift network includes a splitter for receiving an input signal and providing outputs which are coupled through all pass networks to produce signals differing in phase by a predetermined angle. The signals from the all pass networks are coupled through variable attenuators having their outputs recombined in a combiner to produce an output representing the input signal phase shifted by a predetermined angle. The phase shift may be adjusted by changing only one variable attenuator at a time to produce phase shifts of 90.degree. or greater.

Abstract: A circuit capable of vector magnitude control and phase reversal for a radio signal such as an intermediate frequency signal. The circuit includes an inverting signal path and a noninverting signal path and means for selecting between the two. Further, a variable attenuation controllable from a function control input establishes the magnitude of the output signal vector. There is also disclosed a phase shifter employing two such circuits. In the phase shifter, a radio signal vector to be shifted is applied to the inputs of the two circuits, with a 90.degree. shift between the two inputs. With proper vector magnitude and phase reversal control of the two circuits, there can be provided a preselected phase shift in any quadrant.

Abstract: A signal coupling circuit suitable for use in a high-speed signal acquisition probe comprises separate high-frequency and low-frequency signal transmission paths from input to output. The low-frequency path includes a mechanism for variably shifting the DC voltage level at the circuit input to offset quiescent or average voltage levels of an input signal. Values of impedance elements for both the high-frequency and low-frequency transmission paths may be selected to provide predetermined input and output impedances without compromising signal fidelity or limiting signal bandwidth.

Abstract: For damping undesired high frequency electromagnetic oscillations on HF technology components, such as coaxial lines, waveguides and resonators, as well as for the use in resonant circuits of VHF amplifiers with high HF power electron tubes, an absorber is proposed, which can be stablely coupled in mode-selective manner, while having a negligible influence on undesired low frequency and/or other electromagnetic oscillations, while having a predetermined high-pass characteristic.Absorber elements are used, which comprise a pocket made from a material having a high electrical conductivity with an opening on one longitudinal side and surrounding a ferritic, dielectric or ohmic absorber rod.For amplifying the absorption effect and for the predetermined setting of the absorption direction, a plurality of these absorber elements can be arranged with a predetermined geometry with respect to the component generating, transporting and/or emitting the HF power.

Abstract: An improved signal input circuit suitable for use in wideband oscilloscopes includes a high impedance controllable attenuator stage.

Abstract: A programmable attenuator includes MOS FET switches to electronically select a plurality of attenuation factors in a 1-2-5 step sequence. Such an attenuator is particularly suited for use in the input circuit of an oscilloscope.

Abstract: In a predetection combiner there is provided AGC amplifier which uses an electronically controlled RF attenuator, such as a PIN-diode attenuator, which is linearly controlled by use of digital signals. A programmed read-only-memory provides a linearity correction for generating the appropriate control voltage for the diode attenuation device.

Abstract: A compensation method and apparatus for a roughly compensated RC attenuator using fixed resistors and fixed capacitors. Any difference of the high frequency attenuation ratio from the low frequency of DC attenuation ratio is detected and corrected by using multiplier for increasing or decreasing high frequency components at the output from such RC attenuator, thereby allowing digital or remote compensation of RC attenuator without using variable capacitors.

Abstract: An integratable programmable attenuator includes in one embodiment a plurality of field-effect transistors coupled to a semiconductor resistor at spaced apart locations thereon, the semiconductor resistor forming one of the source/drain regions of each of the transistors. The other source/drain region of each field-effect transistor is selectively coupled to an input of a differential amplifier, the output of which is coupled to one end region of the semiconductor resistor. The gain of the differential amplifier is variable in predetermined steps according to which of the transistors is selected.

Abstract: A microwave absorber is provided for use as lining in an anechoic chamber for positioning on the sides of the chamber, especially in the area about midway between the source and receiver, the absorber element being designed to augment chamber performance by effectively increasing the angle of incidence of radiation at the absorber, yielding an improved performance.