Abstract: An audio system comprising an electro-acoustic transducer having two stacked voice coils mechanically linked to a membrane. The voice coils are oscillatingly suspended in the magnetic field of a permanent magnet focused by a pole plate and are mechanically arranged symmetrical to the pole plate while in a rest position. The audio system further comprises two driver circuits connected to the electro-acoustic transducer.

Abstract: A number of position sensors inductively sense a target's position relative to a number of sensor coils. The target is magnetically coupled with first and second coils so that signals are generated that depend on the relative position of the target and the first and second coils. Substantially all of the target overlaps with loops of the first coil and so that when a first end of the target is adjacent a first loop of the first coil, a second end of the target is adjacent a second loop of the first coil that has an opposite winding direction to that of the first loop. The second coil is arranged relative to the target such that the magnetic coupling between the second coil and the first end of the target is opposite to the magnetic coupling between the second coil and the second end of the target.

Abstract: A transformer, adapted for being configured in a wiring substrate, is provided. The transformer includes a first plane coil and a second plane coil. The first plane coil includes a plurality of first loops. The second plane coil includes a plurality of second loops. A first bundle constituted by at least two adjacent first loops and a second bundle constituted by at least two adjacent second loops are stridden one over another.

Abstract: In a linear position encoder, a support is provided upon which a pair of phase quadrature windings are mounted. The windings are arranged to have a sinusoidal magnetic sensitivity characteristic along the length of the support. Mounted on a movable element there is a resonant circuit including a coil and capacitor that can magnetically couple with the windings. When the circuit is excited, it induces currents in the windings that are dependent upon the position of the circuit within a period Ts of the windings. An excitation and processing unit is provided to energize the circuit and to process the signals induced in the windings. The excitation and processing unit is operably coupled to an external high permeability rod extending along the measurement path in a first plane having the windings but removed therefrom. The rod has first and second excitation coils connected in series and wound around the rod and disposed at opposite ends defining a length of the rod.

Abstract: Processing circuitry is provided for processing signals received from, for example, sense coils forming part of a position encoder used to encode the relative positions of two relatively movable members. The position encoder is such that each of the plurality of signals from the sense coils varies sinusoidally with the relative position of the members but out of phase with respect to each other. The processing circuitry comprises mixers for multiplying each of the received signals with one of a corresponding plurality of periodic time varying signals, each having the same predetermined period and a different predetermined phase, and an adder for adding the signals from the mixers. The phase of the mixing signals are chosen so that the output signals from the adder contains a single periodic component having the predetermined period whose phase varies with the relative position of the two members.

Abstract: A scale loop formed by a loop trace of electrically conductive material is usable in an induced current position transducer. The scale loop is continuous and has a particular shape depending on the configuration of the induced current position transducer. The scale loop is not in contact with other highly conductive materials. The dimensions of the cross-section of the conducting trace are chosen to increase the transfer of energy through the transducer.

Abstract: A electromagnetic induction-type absolute position transducer according to the present invention has a plurality of scale loops functioning as coils. The scale loop has first and second loop portions and a connecting pattern portion which connects the corresponding first and second loop portions with each other. The first and second loop portions are arranged along the measuring axis at different wavelength intervals. At least part of the pattern widths constituting scale loops are gradually increased as the length of a connecting pattern portion becomes longer.

Abstract: A position detector is provided for detecting the relative movement of first and second members which are mounted for relative movement along a measuring path. One of the members comprises a magnetic field generator for generating a magnetic field and the other member comprises first and second conductors which are inductively coupled to said magnetic field generator. The arrangement of the first and second conductors and the magnetic field generator is such that output signals are generated in a first and second receive circuits whose position varies with the relative movement between the two members. In addition to carrying information relating to the relative position between the two members, the signals induced in the receive circuits also comprise information defining the relative orientation of the two movable members, and by suitable processing of the received signals the relative orientation of the two members can also be determined.

Abstract: An inductive absolute position sensor has at least one magnetic field generator that generates a first changing magnetic flux in a first flux region. A plurality of coupling loops have a first plurality of coupling loop portions spaced at an interval related to a first wavelength along a measuring axis and a second plurality of coupling loop portions spaced at an interval related to a second wavelength along a measuring axis. One of the first plurality of coupling loop portions and the second plurality of coupling loop portions are inductively coupled to a first changing magnetic flux from a transmitter winding in a first flux region to generate a second changing magnetic flux outside the first flux region in the other of the first plurality of coupling loop portions and the second plurality of coupling loop portions. A magnetic flux sensor is positioned outside the first flux region and is responsive to the second changing magnetic flux to generate a position-dependent output signal.

Abstract: A position detector is provided for detecting the relative movement of first and second members which are mounted for relative movement along a measuring path. One of the members comprises a magnetic field generator for generating a magnetic field and the other member comprises first and second conductors which are inductively coupled to said magnetic field generator. The arrangement of the first and second conductors and the magnetic field generator is such that output signals are generated in a first and second receive circuits whose position varies with the relative movement between the two members. In addition to carrying information relating to the relative position between the two members, the signals induced in the receive circuits also comprise information defining the relative orientation of the two movable members, and by suitable processing of the received signals the relative orientation of the two members can also be determined.

Abstract: A reduced offset position transducer uses at least one coupling loop on a scale to inductively couple a transmitter winding on a read head to one or more receiver windings on the read head. The transmitter winding generates at least one primary magnetic field. The transmitter winding is inductively coupled to first loop portions of the coupling loops by the primary magnetic field. Second loop portions of the coupling loops generate secondary magnetic fields. Each receiver winding is inductively coupled to the second loop portions of the coupling loops by the secondary magnetic fields. At least one of the transmitter winding or the receiver windings is formed in a periodic pattern complementary to the dimensions of the coupling loops. Prescribed winding configurations are used to reduce the effects of extraneous inductive coupling in the device.

Abstract: In a linear position encoder, a support is provided upon which a pair of phase quadrature windings are mounted. The windings are arranged to have a sinusoidal magnetic sensitivity characteristic along the length of the support. Mounted on a movable element there is a resonant circuit including a coil and capacitor that can magnetically couple with the windings. When the circuit is excited, it induces currents in the windings that are dependent upon the position of the circuit within a period T.sub.s of the windings. An excitation and processing unit is provided to energize the circuit and to process the signals induced in the windings. The encoder may in a variation, measure rotational or radial position instead of translation.

Abstract: A pickup device has a core to which a coil is wound about. The core has a body formed by laminating a plurality of plates having a predetermined shape. Eddy currents produced by leakage flux is suppressed at the ends of the core. This is achieved by laminating a plate, which has a certain shape and is made of a material having a higher electric resistance value than the body, to the ends of the body. The generation of eddy currents may also be suppressed by providing notches at the ends of the core to obstruct the formation of a magnetic circuit at the ends. As another option, space may be provided at the ends of the core to disconnect the path of eddy currents.

Abstract: In an electromagnetic induction type displacement sensor, two coil patterns are formed on a substrate included in a scale. The coil patterns alternate with each other in the sensing direction of the sensor and are deviated in spatial phase from each other by a quarter pitch. An idle pattern portion is included in one or both of the two coil patterns in order to provide them with the same impedance. Even when sinusoidal voltages, which are different in phase by 90 degrees, are respectively applied to the coil patterns, the resulting magnetic fields are identical and insure accurate displacement detection.

Abstract: In an induction sensor, a plurality of positioning holes are formed through each of a scaler and a slider. The positioning holes of the scaler and slider are spaced the same distance from respective coils and are of the same size and arranged at the same interval. The gap length and azimuth angle between the scaler and the slider are maintained with accuracy.

Abstract: A magnetic levitation transport system includes magnetic levitation vehicles each driven by a linear motor to run along a track. Induction lines extend through predetermined blocks of the running track to transmit a high frequency sine-wave current. Each vehicle includes electromagnets to attract levitating magnetic members extending along the running track, a pickup coil resonant with a frequency of the induction lines to generate an electromotive force, and a battery chargeable by the pickup coil. The electromagnets receive power from the pickup coil and/or the battery.

Abstract: A sensor having a wide sensing range is capable of being controll by a small scale processor. The sensor comprises: a plurality of planar zigzag coils being provided on substrates, the planar zigzag coils having the same coil pitch and being formed into zigzag shape in a first direction, the planar zigzag coils being capable of relative movement in the first direction, the planar zigzag coils including a first planar zigzag coil, which is a primary coil, and a second planar zigzag coil, which is a secondary coil; a magnetizing unit for magnetizing the first planar zigzag coil; a first detecting unit for detecting induced electromotive force, which is induced in the second planar zigzag coil by the first magnetized planar zigzag coil; and a second detecting unit for detecting displacement length between the first planar zigzag coil and the second planar zigzag coil on the basis of the induced electromotive force in the second planar zigzag coil.

Abstract: In the representative embodiment of the new and improved apparatus disclosed herein, the apparatus, including a core of a specific material, couples a first unit to a second unit. The first unit may, for example, be a downhole tool, the second unit being surface equipment. The first unit may also be a video recorder or television camera, the second unit being a television monitor. The downhole tool adapted to be coupled in a pipe string and positioned in a well bore is provided with one or more electrical devices cooperatively arranged to receive power from surface power sources or to transmit and/or receive control or data signals from surface equipment. Unique inner and outer coil assemblies arranged on cores of a specific material are arranged on the downhole tool and a suspension cable for electromagnetically coupling the electrical devices to the surface equipment so that power and/or data or control signals can be transmitted between the downhole and surface equipment.

Abstract: For enabling a resolver to have absolute position sensing over a wide displacement range while still obtaining the resolution, accuracy and precision obtainable by operation in an incremental mode, the resolver is provided with a number of terminals for providing offset pitch phase indications as a function of position. A microcomputer is programmed to execute a decoding procedure for reading the offset pitch phase indications and from them computing the absolute position. This method is applicable to linear as well as rotary position sensing. By using multiplexing, digital signal processing and large-scale circuit integration of interfacing the resolver to the microcomputer, the method can achieve absolute position sensing with high reliability and low cost. The offset pitch phase indications are readily provided by inductive coupling between a multiplicity of windings, including a set of offset pitch windings connected to the terminals.

Abstract: An electrical proximity identification system which has lateral flux. The system has a reader section with a reader antenna which is comprised of a pair of coils. The coils are located in the same plane and are oriented such that when they are energized by radio frequency power, the flux lines travel between the coils in a direction parallel to, but above and below, said plane. The system also has an identifier section with an identifier antenna. The identifier antenna is positioned such that its axis is parallel to the plane and in line with the flux lines.

Abstract: A transducer converts the amount of mechanical displacement of a member into an electrical signal by magnetic induction. Two fixed coils different in winding direction from each other are spaced apart from each other by a suitable distance and connected in series. Inside the fixed coils, a movable coil is disposed which moves in cooperative association with the member whose amount of movement is to be detected. With the movable coil supplied with an a.c. current, the fixed coils produce an induction current whose amplitude varies with the relative position of the movable coil. A signal processing circuit generates a pulse having a duty ratio corresponding to the amplitude of the induction current. This pulse is converted into a d.c. current in a smoothing circuit to obtain a d.c. voltage corresponding to the amount of mechanical displacement.

Abstract: A transducer, especially suitable for monitoring welds (22), in a sodium-cooled nuclear reactor, has two plates (11, 12) in sliding face contact with parallel slots (13, 14) holding inductively coupled conductors (15, 17). One plate (12) is connected directly to one side of the weld and the other plate (11) is connected via an arm (23) and spacer (24) to the other side of the weld. Multiple slots and conductors can be employed to remove ambiguity from measured signals from the transducer. Multiple transducers can be employed in a scanned X-Y matrix.

Abstract: This invention relates to method and apparatus for improving the accuracy of optical or electrical position measuring apparatus wherein movement of one object relative to another is measured. One known system employs primary and secondary windings each comprising a multiplicity of series-connected conductors arranged on adjacent faces of relatively movable members of insulating material. In another system an optical Moire fringe pattern is moved in correspondence as regards extent and sense with the movement with the object and the number of fringes displaced from a fiducial line are counted.

Abstract: A parallel resonant electric circuit comprising a first and second concentric electrical coil wound in the same directions with the convolutions of the one coil between the convolutions of the other coil and with one end of one coil connected to the opposite end of the other coil, and a third electrical coil extending within the first and second coil if it is desired to tune the parallel resonant circuit.

Abstract: An electrical frequency responsive circuit comprising a first coil constructed of wire having an insulating coating thereon wound in a single layer about an axis of generation, and a second coil, also constructed of wire having an insulating coating thereon wound about an axis of generation in a single layer, said coils being axially related and having diameters and/or pitch to provide inductance and capacitance between the coils which is at least initially adjustable whereby the circuit is responsive to an electric signal having a predetermined electrical frequency imposed across the coils to provide frequency band suppression about the predetermined frequency.

Abstract: A member of a linear position measuring transducer is provided with a hole running parallel to its windings. In one embodiment, elements are inserted into the hole to expand or shorten the length of the transducer. In another embodiment, cutout slots are made between quadrature sections of windings and the elements are introduced into the hole to alter the relative spacing between these quadrature winding sections.

Abstract: A harness for an electromagnetic transducer such as an INDUCTOSYN-type slider includes four separate series of thin flat U-shaped connectors stacked on top of each other for connecting the ends of the U-shaped conductors on the slider to each other in the desired pattern. Each separate series of connectors are separated from each other by a thin film of insulating material, with the ends of each connector projecting beyond one edge of the insulating film to form tabs which are aligned with the ends of preselected U-shaped conductors for connection thereto. The end tabs of the connectors may be joined to the conductors by a single soldering operation, and the entire harness assembly may be prefabricated by laminating the four series of connectors to each other. The connectors are formed by printed circuit techniques.

Abstract: A precision transducer for position measurements comprises a pair of supports, one of which is movable with respect to the other. Each support is provided with an electric winding constituted by equidistant serially connected printed circuit conductors extending transverse to the direction of movement. The winding of one of the supports comprises a plurality of groups of conductors connected in series and intercalated with the conductors of the other group(s). Each group of conductors is printed on one face of a substrate, the other face of which bears auxiliary conductors connecting the conductors of the groups in series, through metallized holes formed through the substrate. The substrate is bonded to the said one support after the printing of the auxiliary conductors on the said other face, the groups of conductors being printed on the said one face after the substrate has been bonded to the support.

Abstract: An electrical frequency responsive circuit comprising a first relatively larger diameter coil constructed of wire having an insulating coating thereon wound in a single layer about an axis of generation, and a second relatively smaller diameter coil having an outer diameter slightly larger than the inner diameter of the first coil, also constructed of wire having an insulating coating thereon wound about an axis of generation in a single layer. One end of the second coil is screwed into one end of the first coil a distance to provide inductance and capacitance between the coils whereby the circuit is responsive to an electric signal having a predetermined electrical frequency imposed across the other ends of the coils to provide frequency band suppression about the predetermined frequency.

Abstract: A transducer for measuring linear positions comprises a scale formed of a tensioned flexible band and a slide movable with respect to the scale. A rigid guide plate fast with the slide extends over the whole area of the slide winding and cooperates with a resilient plate having guide lugs at each end of the guide plate and so bent as to have lips bearing against two edges of the band. A leaf spring element on the resilient plate urges the lips against the side of the band opposite to the plate.

Abstract: An inductive transducer includes first and second relatively movable members, the first relatively movable member having a plurality of windings and the second relatively movable member having a winding. The windings of the first relatively movable member each have a pair of terminals and are each arranged in a pattern comprised of a first section coupled to one of the terminals and a second section coupled to the other terminal and to the first section. Each section includes a plurality of conductors oriented substantially parallel to one another wherein immediately adjacent conductors of such section are capable of conducting current in opposite directions and are coupled to one another by an end-segment arranged substantially perpendicular to the conductors.

Abstract: A linear position measurement system including a linear member and a relatively movable member. The linear member includes a plurality of serpentine electrical conductors, each representing one bit of a multiple bit Gray code. At any longitudinal position of the movable member, an inductor in the movable member induces oppositely phased signals in those conductors which lie along a first long edge of the linear member and in those which lie along an opposite edge. A phase comparator in a readout device attached to the conductors compares the signals from each conductor with a reference and constructs a unique address code word indicative of the position of the movable member. The inductor in the movable member is activated through a special circuit which is powered by inductive coupling with a coil carried by the linear member.

Abstract: A digital displacement sensor includes a plurality of zigzag coils provided with projecting or convex portions having different pitches and arranged on the surface of a flat plate. A magnetic head consisting of a magnetic body and a coil is wound around part of the magnetic body, the magnetic head being supported so as to be moved, while maintaining a given gap from the surface of the flat plate, whereby a digital signal corresponding to the displacement of the magnetic head is sensed by means of a plurality of zigzag coils.

Abstract: Inductive position determining device which comprises a signal winding having meander curves which extend at right angles to the direction in which displacement is determined and two pick-up windings which have corresponding meander curves. The meander curves have a given width and the meander curves of the two pick-up windings show intervals of increased width in which at least one of the meander curves of the other pick-up winding is accommodated. By special proportioning of the limbs of the meander curves the mean medians of the limbs of the two pick-up windings coincide. As a result the position determining device becomes largely insensitive to rotation errors between the carriages on which the signal winding and the pick-up windings respectively are placed.

Abstract: A position detecting system includes a sending unit in the form of a continuous conductor describing a Greek key pattern surrounded by a return-path conductor arrangement. The return-path conductor is so arranged as to provide additional legs of the pattern with the widths and spacings of such additional legs with respect to adjacent legs of the pattern being such as to assure a magnetic effect producing well defined and evenly spaced node and antinode signals in an associated pick-up head.

Abstract: An apparatus for charging an electrical energy source secured within a water-tight or hermetically sealed housing. The apparatus includes a transformer having a primary and secondary coil. The secondary coil is secured within the housing, whereby the housing need not be opened to effect charging of the electrical energy source.