Abstract: An inductive sensor is driven by a series resonant oscillator circuit to produce an oscillator signal having a frequency which is a function of inductance of the inductive sensor. An inductive load, which includes the sensor, is connected in series with a capacitive impedance. Power to the series resonant circuit formed by the inductive load and the capacitive impedance is controlled as a function of current in the series circuit as sensed by a current sensor. A detection system provides a detector output based upon the frequency of the oscillator signal.

Abstract: A preamplifer for use with a magneto-resistive playback head in which a d.c. current source provides current through a field effect transistor and the magneto-resistive element to ground. An operational transconductance amplifier included in a feedback loop provides a bias voltage for the field-effect transistor, whereby the voltage across the said magneto-resistive element is held constant while the resistance of said element changes. The resulting a.c. current flowing through the magneto-resistive element flows only through the feedback loop and an output resistor connected across the inputs of the operational transconductance amplifier. The amplification of the circuit is approximately the resistance of the output resistor divided by the resistance of the magneto-resistive element.

Abstract: A wide-band differential amplifier includes four MOS transistors connected in a source-follower configuration for gm-cancellation. Accurate gain and low distortion of the amplified signals results over the frequency band.

Abstract: A marker for use in magnetic-type electronic article surveillance systems, comprising a substrate on which are deposited a plurality of high permeability, low coercive force magnetic thin-films, each being separated from an adjacent magnetic thin-film by a non-magnetic thin-film. Each of the magnetic films have substantially the same permeability and coercive force, and the non-magnetic films are of a thickness to allow magnetostatic coupling while inhibiting exchange coupling. Accordingly, all of the magnetic thin-films reverse as a single entity and produce a sharp, readily distinguishable response.

Abstract: Disclosed is a method for reading or writing data on a tape which has a plurality of data tracks and at least a first dedicated servo track. A multiple channel head with at least three channels, each having at least one element for reading or writing, is used to access the tracks on the tape. The head is moved proximate one of a plurality of predetermined positions. The channels are located so that, in any one predetermined position of the head, one channel accesses the center of a dedicated servo track on the tape and at least two other channels will access the center of distinct data tracks. Depending on the predetermined position of the head, different channels will access a dedicated servo track. The position information on a dedicated servo track is used to move the head to one of the predetermined positions once the head has been moved proximate that predetermined position.

Abstract: A radiant energy transmitter for use with a motor vehicle wherein operation of the triggered radiant energy device of the transmitter is altered via an operation altering circuit portion when an alteration initiating switch assumes its alteration mode. Such alteration mode is automatically assumed when the operator carries out an action that is normally done after the motor vehicle is stopped. The operation altering circuit portion continues the altered operation even though the alteration mode of the alteration altering switch is subsequently discontinued.

Abstract: A universal lattice assembly for use in a magnetic type electronic article surveillance system is disclosed which comprises a frame formed of two identical molded plastic half-shells, a metal chassis within which specific electronic sub-assemblies may be positioned and a coil assembly including a drive coil and a sense coil. The housing is adapted to enclose and to interlock and index the chassis, while also rigidly anchoring the coil assembly within an extensive cavity to prevent unwanted movement of the coil. A null adjustment mechanism within the frame enables a slight precise displacement of a coil to enble nulling of the two coils with respect to each other. Upon insertion of the coil assembly and chassis within the half-shells, the two are permanently pinned and bonded together to form an exceptionally rigid and durable composite lattice.

Abstract: An radiant energy transmitter that includes a d.c. to d.c. converter, a d.c. energy storage circuit portion, a triggered radiant energy signaling device, a trigger pulse circuit to initiate operation of the signaling device and an operator adjustable trigger pulse timer circuit portion supplying signals to the trigger pulse circuit at a repetition rate selected by an operator with each signal causing the trigger pulse circuit to provide a trigger pulse to initiate an operation of the signaling device.

Abstract: An improved power supply circuit for supplying power to intermittently energized loads, such as gaseous discharge tube devices. Such power supply has a transformer wherein current flow in the primary winding is controlled by a first semiconductor device that in turn is controlled by a second semiconductor device. A feedback circuit coupled to the primary winding provides a signal for turn-off of the first semiconductor device when its turn-off is initiated by the second semiconductor device. A circuit portion connected between the primary winding and the second semiconductor device provides a signal to the second semiconductor device when it initiates a turn-off of the first semiconductor device. Such signal continues operation of the second semiconductor device until the turn-off signal from the feedback circuit is effective to turn-off the first semiconductor device serving to reduce power dissipated in the first semiconductor device.

Abstract: A multi-directionally responsive, dual-status marker for use in electronic article surveillance systems having an alternating magnetic field within an interrogation zone. The marker comprises a piece of a high permeability, low coercive force magnetic material substantially coextensive with a piece of remanently magnetizable material, in which the first piece is configured to exhibit at least two elongated responsive areas adjacent to edges of the piece perpendicular to each other, each area having a narrow width region forming a switching section and adjacent extensive regions forming flux collectors. In a preferred embodiment, the inner edges of all of the regions are defined by a narrow band of removed material, the remaining material in the center thereby being magnetically isolated from the responsive areas. The marker is desensitized by uniformly magnetizing the pace of unmagnetizable material.

Abstract: An assembly having a gaseous discharge tube and circuitry therefore that is operable for providing light signals for the control of traffic control lights. The assembly is mountable as a part of a light bar assembly of the type mounted on police vehicles. The assembly includes a U-shaped channel member having a hollow protrusion with an opening with the gaseous discharge tube and the reflector therefor secured to the U-shaped member at the opening with the circuitry, which is mounted on a circuit board, carried by a support member that is secured to the U-shaped channel member. The support member has a portion that prevents moisture from reaching the circuitry.

Abstract: A slide and latch bracket for releasably securing an article to a mounting surface. The bracket comprises first and second members, each being adapted to be secured to either the article or mounting surface. The first member is shaped to provide a substantially flat, U-shaped channel having side walls for slideably receiving the second member. The second member also has a flat base, side rails adapted to be received along the side walls of the first member, and a releasable latch for bearing against a mating portion of the first member for locking the members together.

Abstract: A dual status marker for use in electronic article surveillance systems having an alternating magnetic field. The marker comprises a magnetic responder element having a central switching portion and flux collectors on each end which concentrate flux within the switching portion to ensure that the flux density therein is sufficient to generate an appropriate response. The marker is made dual status by providing magnetizable keeper elememts adjacent the flux collectors. When the keeper elements are magnetized, the associated field biases the flux collectors and inhibits magnetization reversal therein in response to an interrogation field, thereby preventing flux from the interrogation field from being concentrated in the switching portion of the responder element.

Abstract: An apparatus for providing a map-like display of weather phenomena such as lightning discharges, in which the distance from an observation location to the source of the discharge is determined from the ratio of the integrated intensity of two different components of lightning produced signals, the intensity of the first component varying as the inverse of the distance and the intensity of the second component varying as the inverse of the square of the distance.

Abstract: A magnetic marker for use with electronic article surveillance (EAS) systems in which a two-directional response is obtained. The marker comprises a substantially two-dimensional, sheet-like substrate having multiple metallic filaments randomly dispersed in or adhered thereto, so as to be substantially parallel to the plane thereof. The filaments are selected of low coercive force, high permeability material, and the random orientation results in certain filaments intersecting with the being magnetically coupled to other filaments to thereby collect and concentrate lines of flux associated with an applied field of an EAS system into filaments parallel to the field.

Abstract: A magnetic marker for use with electronic article surveillance (EAS) systems in which a two-directional very high order harmonic response is obtained. The markers comprise two pairs of elongated strips of low coercive force, high permeability material positioned in a tic-tac-toe configuration such that the strips at right angles to an applied field of an EAS system collect and concentrate the lines of flux associated with the field into the strips parallel to the field, the concentrated flux being sufficient to result in a high harmonic response.

Abstract: A dual status marker for use in electronic article surveillance systems having an alternating magnetic field. The marker comprises a magnetic responder element having a central switching portion and flux collectors on each end which concentrate flux within the switching portion to ensure that the flux density therein is sufficient to generate an approximate response. The marker is made dual status by providing magnetizable keeper elements adjacent the flux collectors. When the keeper elements are magnetized, the associated field biases the flux collectors and inhibits magnetization reversal therein in response to an interrogation field, thereby preventing flux from the interrogation field from being concentrated in the switching portion of the responder element.