Abstract: In certain embodiments, an ophthalmic diagnostic system includes a laser source, a galvanometer, and a system inverting controller (SIC) coupled to the galvanometer. The galvanometer includes one or more optical elements and one or more galvanometer controllers configured to manipulate an orientation of the one or more optical elements to scan the output of the laser source across an ophthalmic target based on galvanometer control signals. The system inverting controller (SIC) is configured to modify input galvanometer control signals based on an estimated transfer function of the galvanometer and provide the modified galvanometer control signals to the galvanometer.

Abstract: Methods and systems for implementing a rotation sensing device are provided. The rotation sensing device may include a magnet, a magnetic field sensor located in a fixed position relative to the magnet, the magnetic field sensor configured to sense a magnetic field of the magnet, and a flux conductor configured to alter the magnetic field of the magnet, wherein the flux conductor is mounted to a rotatable element. The magnet may be mounted in a fixed position relative to the flux conductor, and the magnetic field sensor may be configured to generate a signal based on a sensed strength of the magnetic field in accordance with rotation of the flux conductor.

Abstract: Method in which the current is measured inside an integrated PWM control circuit using at least one A/D converter which is likewise integrated in the circuit is described. The PWM controller is provided for the purpose of driving inductive loads and is arranged, in particular, in an electronic circuit of an electronic controller for a motor vehicle braking system. Before determining the actual current of the PWM controller, which is determined using the at least one A/D converter, the current is smoothed using a low-pass filter. A circuit arrangement for carrying out the above method and its use in electronic motor vehicle control systems is also described herein.

Abstract: The invention relates to an electronic motor vehicle control system having at least one valve actuating circuit which controls a load current by means of pulse width modulation. The actuating circuit has at least one electronic current measuring circuit which has at least one measurement path with at least one analog/digital converter. The analog/digital converts an analog measurement signal of the load current into a digital measurement signal of the load current and is actuated or designed in such a way as to carry out a plurality of current measurements per PWM period. The at least one measurement path of the current measurement circuit has a signal conservation circuit which provides the analog measurement signal of the load current substantially unchanged, and independent of the actual load current, for at least a defined hold time (toff->on, ton->off).

Abstract: An electronic controller for motor vehicle control systems having at least one valve actuation circuit is described herein. The electronic controller uses pulse width modulation to control the load current (iL) flowing through an essentially inductive load (L), and has at least one electronic current measuring circuit which has at least one analog/digital converter which converts an analog measurement signal for the load current (iL) into a digital measurement signal for the load current (iL). The at least one analog/digital converter is a sigma-delta modulator. A method for measuring current using sigma-delta modulation and to the use of the electronic controller in a motor vehicle brake system is also described herein.

Abstract: Method in which the current is measured inside an integrated PWM control circuit using at least one A/D converter which is likewise integrated in the circuit is described. The PWM controller is provided for the purpose of driving inductive loads and is arranged, in particular, in an electronic circuit of an electronic controller for a motor vehicle braking system. Before determining the actual current of the PWM controller, which is determined using the at least one A/D converter, the current is smoothed using a low-pass filter. A circuit arrangement for carrying out the above method and its use in electronic motor vehicle control systems is also described herein.

Abstract: An engraving element of an electronic engraving machine for engraving printing forms is formed of a shaft oscillating around a longitudinal axis with small rotational angles. A drive system is provided for the shaft with a lever attached to one end of the shaft. An engraving stylus is provided for engraving the printing form, along with a restoring element for the shaft, a bearing for the shaft, and a damping mechanism for the shaft having a damping element secured to the shaft and a stationary damping chamber. The damping element comprises at least one damping disk that is designed circularly at least in regions and extends perpendicular to the shaft. The damping chamber is designed at least as a hollow-cylindrical segment around the shaft into which the damping disk projects and extends at least over the circular region of the damping disk. The damping chamber is filled with a ferro-fluidic fluid as a damping agent.

Abstract: A structure for reducing shock transmitted from a source (6) to an equipment unit (7) in a hardware system, which structure includes a honeycomb cellular support member (2, 3, 4 or 5) carrying the equipment unit to be protected from shock and/or the source. At least some of the honeycomb cells are filled with rigid microgranules whose dimensional characteristics are preferably heterogeneous, within given limits.

Abstract: Moving magnet indicating instruments in which a damping fluid migration barrier projects from the inside of one wall of the bobbin coil and another damping fluid migration barrier projects from the face of the rotor which confronts that wall. Certain fluids have a tendency to migrate, or “creep,” over surfaces they contact. The fluid migration barriers of the present invention prevent unwanted migration of fluid out of a cavity by providing a sharp peak over which the fluid cannot creep.

Abstract: Moving magnet indicating instruments in which a damping fluid migration barrier projects from the inside of one wall of the bobbin coil and another damping fluid migration barrier projects from the face of the rotor which confronts that wall.

Abstract: A bobbin assembly for a vehicle instrument gauge is provided. The bobbin assembly includes an upper and a lower bobbin, which together define a chamber therebetween and an axis of rotation therethrough. The bobbin assembly also includes a permanent magnet rotatably disposed within the chamber. A shaft rotatably supports the magnet within the chamber for rotative movement about the axis of rotation, and a viscous damping fluid, carried in the chamber, damps the rotational movement of the magnet. The upper bobbin includes a nose portion defining a bore therethrough which extends along the axis of rotation. The bore is open to the chamber and receives the shaft therethrough. The nose portion also defines an inner dam portion disposed within the chamber. The upper bobbin further includes a trough which is in fluid communication with the chamber and extends radially outwardly from the inner dam portion.

Abstract: A meter driving system receives pulse signals from a sensor, counting frequencies or periods of the input signals. The counted results are weight-averaged to determine an output value and a value to be indicated. In a weight-averaging process, a weight is varied in response to the frequencies of the input signal. Thus, the meter can give a precise indication regardless of varying input frequencies.

Abstract: An indicating instrument having a cross coil comprising a pair of mutually perpendicular coils wound on a coil bobbin for passing therethrough current changing with changes in the quantity to be measured, a magnet rotor disposed inside the coil bobbin for rotating in the direction of a magnetic field which is the combination of the respective magnetic fields generated by the cross coil, and a pointer for indicating the measured quantity which is mounted on a rotary shaft rotatable together with the magnetic rotor. In order to prevent unneccessary vibration of the rotary shaft, the rotary shaft is acted on by a damping force of a viscous liquid. The viscous liquid is accommodated in a recess formed in the upper surface of the magnet rotor, and the damping action is performed in cooperation with a damping projection projecting downward from a part of the coil bobbin.

Abstract: An air-core meter having a two-piece bobbin enclosing and surrounding a moveable magnet within a sealed cavity containing a damping fluid. The magnet is rotated about the axis of a supporting shaft by a plurality of orthogonally related windings disposed about the outer surface of the bobbin. The air-core meter provides improved and simplified assembly, improved reliability and reduced damage in routine operation and service through novel bearing design and bobbin structure. Furthermore, improved meter performance is provided by specific winding geometries and magnetic structure design.

Abstract: An apparatus for ferromagnetic measurements of electric quantities comprises a coil having a hollow barrel on which a winding of a conductive wire is formed. A unit which is integral with a needle is positioned in the barrel. The needle is displaced in front of a graduated dial between a zero value and a maximum value. The movable unit is formed integrally with a first metallic plate which is displaced, in the course of the measurement of an electrical quantity, relative to a second metallic plate which is fixed in the hollow barrel of the coil, as a function of the magnetic field created by the winding. At least one additional metallic plate is fixed in the hollow barrel of the coil, in such a manner as to cooperate with the movable plate to generate therewith a repulsive force in order to brake the pivoting of the pivotable unit when the electrical quantity to be measured tends to displace the needle of the movable unit beyond the maximum value of the graduation.

Abstract: User selection of meter ballistics is accomplished by separating the meter display from the meter drive circuitry. An input signal is input in parallel into appropriate level determining circuits, with the outputs being selected for processing by a microprocessor. The microprocessor processes the selected outputs according to a ballistic standard selected by an operator to generate a display signal. For LED displays the display signal has a bar component that illuminates all the LEDs up to the maximum level of the displayed output and a dot signal that illuminates only one or a very few LEDs around the maximum level of the displayed output.

Abstract: A driver circuit for magnetic gages that electrically simulates the gage, both with and without a parallel resistor joined in conjunction therewith. An averaging circuit assists in preventing the circuit from responding to transient variations in the monitored parameter.

Abstract: An improved viscous dampening arrangement for a taut-band suspension system in an electrical indicating instrument includes a hub associated with the stator and a turret associated with the rotor. The hub and turret each have central openings for receiving the taut-band. The hub and turret are arranged, in use, in a spaced-apart facing relationship with the facing portions of hub and turret being tapered in a controlled fashion. A viscous dampening fluid is provided between the hub and turret and an anti-wetting agent is applied to the surfaces of the hub and turret where the dampening fluid is not desired. The geometry of the tapers is chosen so as to minimize the effects of longitudinal and radial shocks and vibrations on the electrical indicating instrument.

Abstract: Signal-processing apparatus for use with industrial instrumentation systems and the like, and comprising a memory to maintain a signal level for long time periods without drift. An input signal level is translated into the positioning of a movable member, through the use of an actuator motor controlled by the input signal and a position feedback signal. A friction device is coupled to the movable member to hold it in any given position, thereby to serve as a memory for the input signal level. The friction device comprises a thin vane-like element which is secured to the movable member and disposed in the air-gap of a permanent magnet. The air-gap also includes a mass of tiny magnetizable particles which, under the influence of the magnetic field, engage the surfaces of the vane-like element to develop a frictional restraining force.

Abstract: Switch means having a predetermined number of switch positions normally applies any selected one of the same predetermined number of separate control signals to a galvanometer in accordance with the switch position to which the switch means is operated. However, in response to each operation of the switch means between switch positions, a reference signal is applied to the galvanometer for a given time. This overcomes the degrading effect of hysteresis on galvanometer accuracy.

Abstract: The change of angular acceleration sensor has a wire wound rotor resiliently mounted for rotation about a sensing axis and has a magnetic field at right angles to the sensing axis and across the wound rotor so that a signal voltage is generated in the windings by the motion of the windings in the field in accordance with the third time derivitive of angular motion of the sensor about its sensing axis.

Abstract: A watthour meter damping assembly includes a U-shaped magnetic yoke and a pair of highly coercive and anisotropic permanent magnets projecting in facing relationship from the ends of the yoke. Opposing pole faces of the magnets form an air gap receiving a meter disc to be magnetically retarded. A single temperature compensator extends over the pole faces of the permanent magnets to form a compensating shunt flux path around the air gap. The compensator and magnetic yoke extend substantially parallel to each other from the inner and outer pole faces, respectively, of the magnet pair.

Abstract: The suspension of movable system instruments, for example, a galvanometer, introduces elastic reset torques upon deflection. To compensate for such torques and render the apparatus essentially independent of the deflection torques, an opto-electronic device provides an output signal representative of the deflection which is combined with the deflection voltage applied to the galvanometer to at least in part compensate for the reset torque introduced by the moving system suspension.

Abstract: An improvement to an electrical measuring instrument having a rotary moving part capable of longitudinal movement in relation to the remainder of the instrument and including a damping arrangement comprising co-operating pads fitted respectively to the moving part and an adjacent fixed part to define a gap between the adjacent surfaces of the pads containing viscous liquid held in position by surface tension, the improvement comprising one of the pads being formed of glass-filled plastics material and the gap, when seen in cross-section, having substantially parallel sides which diverge at the edge of the gap, preferably to define a wide-angled V. Preferably the second pad has a smooth surface and may be formed of a light metal.

Abstract: A recording device which utilizes a closed loop servo system including a limited rotation motor, i.e. a moving coil galvanometer wherein the moving coil is activated by an input signal such that the rotational movement of a shaft supporting such coil may be translated into a graphic display for recording of the input signal. The device has specific utility in the recording of medical information wherein the input signal is created by the patient's body functions but has widespread alternate utility. The device further includes a transducer construction utilizing a rotational resistance mechanism including a rotating hub to which a contact arm is attached that creates a signal proportional to the position of the coil shaft and utilizes this signal for comparison with the input signal such that the coil position and thus that of the shaft may be corrected.

Abstract: In a blood pressure measuring system in which a pressure signal comprised of both applied pressure and pulsatile pressure is detected and subsequently filtered to separate the pulsatile pressure component, circuitry is provided to minimize start-up transients in the separated signal. Such start-up transients, which normally persist for some time after start-up as a result of the AC time constants of the filters, are otherwise capable of generating erroneous measurements. The circuitry initializes the filters by clamping their outputs to predetermined voltage levels during a start-up interval and thereby avoids the generation of the transients.

Abstract: A limited-displacement device is provided with an extended frequency range by critically damping it and compensating its frequency characteristics with a pair of series lead compensation circuits whose break-point frequency matches the natural frequency of the mechanical parts of the system.

Abstract: An improved testing device and method to measure the degree of polarization potential on the interface of a metal structure and its environment where said structure is protected against corrosion through a cathodic protection system.The testing device includes adjustable stop means associated with a conventional electrometer to reduce the excursion of the needle of said meter and thereby achieve a more accurate reading of the polarization potential of the metal structure.

Abstract: A new and improved magnetic damping system for induction watthour meters including electromagnetically driven disk armatures. The magnetic damping system comprises cobalt-rare earth permanent magnets of relatively small mass deployed in a counterposed pair of unit assemblages each of which is positioned on an opposite side of the driven disk.

Abstract: The noisy amplified signal from a photoelectric device is passed through an electronic low-pass filter before having its direct current component read on a meter. The cut-off frequency of the low-pass filter is adjusted in known manner by rotation of a control knob, so as to suitably match the cut-off frequency to the noisiness of the signal with a view towards speeding up the stabilization of the meter reading. To overcome the sluggishness of the system, the same control knob is briefly pushed, thereby overriding the low pass control. The method of using the system to speed up meter reading is described.

Abstract: Signal-processing apparatus for use with industrial instrumentation systems and the like, and comprising memory means to maintain a signal level for long time periods without drift. An input signal level is translated into the positioning of a movable member, through the use of an actuator motor controlled by the input signal and a position feedback signal. A friction device is coupled to the movable member to hold it in any given position, thereby to serve as a memory for the input signal level. The friction device comprises a thin vane-like element which is secured to the movable member and disposed in the air-gap of a permanent magnet. The air-gap also includes a mass of tiny magnetizable particles which, under the influence of the magnetic field, engage the surfaces of the vane-like element to develop a frictional restraining force.

Abstract: A peak detector having rise-time enhancement of input signals is comprised of a feedback amplifier including two input terminals and a feedback circuit which interconnects the amplifier output terminal with one of the input terminals; and a peak detecting circuit, including a capacitor, coupled to the other of the amplifier input terminals. The capacitor voltage is applied as an input signal to the feedback amplifier, and abrupt changes in the rise-time portion of the input signals are detected and are used to vary the amplifier feedback so as to enhance the output signal produced by the amplifier during the rise-time portion.

Abstract: An electric meter particularly characterized by a small number of moving parts and simplified assembly. A coil assembly initially including integral support elements which permit connection of pivot bearings or taut bands is adapted to be accurately positioned for rotation on the supporting base by inserting the assembly into the base. Cooperating locating surfaces on the base and coil assembly provide for accurate positioning of the support elements so the axis of rotation of the coil is in a predetermined position relative to a magnetic circuit of the meter. After insertion of the coil assembly, the bridging elements are severed. A coil support form of unique construction includes motion limiting elements which cooperate with surfaces of the magnetic circuit to limit the permissible extent of movement of the coil, in the event of shock or impact, to positions well within the elastic limit of the supports which mount the coil for rotation.

Abstract: An engraving device having a rotary system including a shaft supported in a bearing for rotation through very small angles, means to oscillate the shaft, an engraving needle carried on a lever attached to one end of the shaft adjacent the bearing and a dampening device characterized by the dampening device being arranged between the bearing and lever and the dampening device applying symmetrical forces on the shaft so that the dampening forces do not create bending forces on the shaft. Preferably the dampening device is located closely adjacent to the lever. A preferred embodiment of the dampening device uses a stationary support having a surface surrounding the shaft and either a closed ring of fluoro-plastic dampening material which is connected to the shaft and surface or two or more fluoro-plastic elements which are circumferentially spaced between the shaft and the surface and connected thereto.

Abstract: A restraining means of mildly magnetic material is adjustably implanted in the rotor disc of a conventional watthour meter. The restraining means interacts with a magnetic field generated by the meter's damping magnet to stop the disc from turning when the rate of energy consumption in the metered circuit is below a predetermined rate. The predetermined rate can be altered by varying the radial distance between the center of the disc and the restraining means and by varying the amount of magnetic material passing through the field of the damping magnet.

Abstract: A galvanometer structure is disclosed for high speed deflection of a light beam, such as that from a laser source. A flexible member is secured at one end in a mount of electrically insulating and magnetically inert material, for example, a plastic block. At the free end of the flexible member, a rotor is secured and this, in turn, has fixed thereto a reflecting element, such as a mirror. The flexible member also carries a variable magnetic field producing means which is arranged relative to the flexible member and at the back side of the mirror. A controllable variable current source is connected to the coil on the flexible member. A portion of the flexible member is reduced in cross section at a distance that is intermediate the ends thereof for greater flexibility in the direction of the reduced cross section.