Abstract: A wireless extension telephone system including a base unit connected to a telephone line and a remote extension unit. Both base and extension units each include a radio receiver and a radio transmitter. Also associated with the base unit is an auxiliary telephone and switch operated intercom signalling means, which when manually operated cause a radio signal to the transmitted to the remote unit for signalling purposes after which conversation may insue between users of the auxiliary telephone and the remote extension unit.

Abstract: One aspect of the invention is an integrated induction speaker which produces coherent high frequency and low frequency output. In this embodiment, the high frequency unit is centered between the two split halves of the low frequency unit. Another aspect of the invention is a configuration for a midrange or bass speaker having a very uniform magnetic field and excellent linearity.

Abstract: A motor drive system which utilizes the relatively poor storage time or turn-off time of Darlington pair power transistors which have typically been used as the driver elements in inverter motor driver applications. It primarily finds use in multiphase systems, such as the six step three phase inverter. The relatively long turn-off time of the power Darlington provides relatively constant collector current to the motor without the need for additional circuitry to provide constant base drive load. An additional circuit automatically and dynamically tailors the motor torque to the load requirements to minimize unnecessary use of electrial energy.

Abstract: A variable speed drive for an AC motor has features to improve the power factor. The system uses a rectifier for converting AC supply voltage into DC voltage on a positive rail and a negative rail. Frequency switches are controlled to alternately connect the rails to the power conductors at a variable rate to define a selected voltage frequency. An amplitude switch is located on one of the rails and controlled to vary the potential between the rails in proportion to the frequency. A current sensor senses the current waveform in one of the conductors and applies it to a phase detector which detects the difference in phase between the current and the voltage. Phase difference pulses are produced which are averaged into an average DC value. The DC value is applied to a demand voltage that controls the amplitude switch to reduce the amplitude to improve power factor.

Abstract: In an exemplary embodiment, switches are provided for controlling operating state, and the like, of a miniature hearing aid. In such hearing aids, it is a precondition that all components, thus the switches as well, be designed very small and function reliably. Therefore, the disclosure provides magnetic switches which exhibit elements whose electrical conductivity can be influenced with magnetic fields. For example, reed contacts or magnetic field responsive semiconductors are employed as such elements. Thus, manual switching can ensue by means of displacing a magnet. Magnetically actuatable switches, however, can also serve to automatically switch on an auxiliary element, for instance a device for improving the reception of a telephone call (induction coil), when a magnetic field present outside of the device, for instance the magnetic field of a telephone receiver, approaches. A hearing aid equipped according to the disclosure is particularly suited for use in conjunction with induction coils.

Abstract: Methods and apparatus for controlling an electric motor effect operation of such motor by electric energization thereof, and derive from a motor winding or from the back electromotive force of the motor an electric signal indicative of motor speed. The motor is thereupon mechanically stalled, and such stalling is detected from a comparison of the derived speed signal and the electric energization. Deenergization of the motor is effected in response to the stalling detected from the latter comparison. Limit switching of electric motors and actuators without limit switches may be provided in this manner.

Abstract: An apparatus for picking-up an image of an object including a solid state image sensor having a number of image sensing elements and an objective lens for projecting the image of the object onto the image sensor is disclosed. In order to remove a curvature of field of the objective lens, the image sensor is curved into a spherical shape having a radius of curvature equal to that of the curvature of field. The solid state image sensor may be curved in any desired shape to correct various aberrations of the objective lens.

Abstract: A digital echo canceller is arranged in a digital telephone circuit for PCM-signals in accordance with a pseudo-logarithmic encoding law, for example the A-law of the CCITT, in the proximity of a subscriber line interface circuit having a codec in order to cancel in the near-end speech signals S supplied by the codec to the send path the echo effect Y of the far-end speech signals X conveyed to the codec by the receive path. The echo canceller has circulating shift registers for the signals X and the coefficients C, digital correlation calculation means for obtaining the coefficients C, digital convolution calculation means for obtaining an echo cancellation signal y and digital subtraction calculation means for obtaining near-end speech signals R in which the echo effect Y has been substantially cancelled.

Abstract: An improved hydro-turbine having a casing with an inlet port and an outlet port. A driveshaft is journaled in the casing and a rotor is secured to the driveshaft. The rotor has a cylindrical member whose radius is at least greater than 50 percent of the radius of the peripheral wall casing. A plurality of vane members extend outwardly from the outer radial surface of the cylindrical member. The vanes are spaced around the perimeter of the cylindrical member and each vane has a front surface and a rear surface. The front surface is substantially flat and the rear surface is convex in cross-section. The bottom edge of the rear of each vane is located substantially adjacent the bottom edge of the front surface of the adjacent vane member. The vane members extend substantially across the entire width of the cylindrical member.

Abstract: Apparatus is provided by which a motor vehicle window can be raised and lowered remotely by the use of a unique circuit which interfaces with the motor provided in the vehicle for such purposes. A hand-held transducer, utilizing either radio frequency energy or ultrasonic energy, is used to provide a momentary signal which activates the circuitry, configured to respond to a first signal by causing the window to be completely lowered. Transmission of a second identical signal will begin to raise the window and will continue to do so only as long as the signal remains activated.

Abstract: The present invention concerns a method and a device for controlling a stepping motor of a timepiece, which permit the power of each drive pulse to be adapted to the value of the electromotive force (V) and/or the internal resistance (R*) of the power supply source (10).In accordance with the invention, at a given moment, a value of a chopping rate (Ha) is determined in dependence on the value of the electromotive force V and/or the internal resistance R* of the power supply source (10), said value being stored, and the chopping rate of each control pulse being adjusted to the stored value.The control device comprises means (13) for supplying a chopping signal (M) to a drive circuit (12) of the motor (11). The chopping rate is determined by information contained in a memory (14). The stored information is periodically corrected in dependence on the value of the electromotive force (V) and/or the internal resistance (R*) of the power supply source (10).

Abstract: In a telephone conference bridge, a conference port amplifier comprises amplifying means for providing signal amplification in both directions, the direction of amplification of the amplifier being switchable such that amplification can be provided selectively in one or other direction of speech transmission, while signals applied in the reverse direction are attenuated. The amplifier is biased in such a manner that, in the absence of any speech signal, the direction of amplification provided by the amplifier is from the conference bridge towards a connected telephone line, and means for detecting the presence of a speech signal applied to the amplifier for transmission from the connected telephone line to the conference bridge is arranged to cause switching of the amplifier to reverse its direction of signal amplification. By this means, the signal to noise ratio experienced by each conferee connected to the conference bridge is reduced when the silent conference bus is in the quiescent condition.

Abstract: In an electric drive for a DC shunt propulsion motor which is supplied from a battery, the armature winding is connected to the battery, and the field winding is connected to the battery via an electronic DC control element. The electronic DC control element is associated with the field winding and also serves as a control element for charging the battery. The DC control element is further equipped with a voltage control device in addition to a current control device. A multiposition switch is arranged so that when the switch is in one position the field winding is connected via the electronic DC control element to the battery, and when the switch is in another position, the electronic DC control element is shunted across the battery.

Abstract: An elevator system having a plurality of elevator cars and supervisory control for directing their movement in a building to efficiently serve the floors therein. The supervisory control divides the floors and service directions therefrom, called scan slots, into sets, with a set being those scan slots served by the same combination of cars. The scan slots are assigned to the elevator cars using a predetermined strategy, with the sets being taken in a predetermined order determined by the number of cars enabled to serve the sets. The strategy breaks out of the rigid set concept when assigning scan slots to cars based upon car calls, to effect a significant improvement in elevator service.

Abstract: An elevator system in which a count is maintained to enable a car to be leveled in the correct travel direction in the event the car stops outside the landing zone of a target floor. The count is incremented each time the advanced car position changes floors, and it is decremented each time the car is level with a floor during the run. If the car lands outside the landing zone, a zero count indicates the car overshot the floor, while a non-zero count indicates undershoot. The count, along with the travel direction of the run, which is stored in memory, thus determines the leveling direction to level the car with the target floor.

Abstract: A blocking oscillator for a reciprocating electromagnetic actuator having a solenoid coil, a detection coil for generating a control signal in response to a charge in the magnetic field generated by the solenoid coil, a silicon Darlington amplifier responsive to the control signal to control the current through said solenoid coil, and a diode connected in series with the collector of the Darlington amplifier rendering the Darlington amplifier immune to reverse voltage and transient signals.

Abstract: A wave energy converter comprising a float group including at least two floats connected by elongated rigid links disposed at a right angle to the direction of incidence of waves, which floats are free from the coastal ground and sea bed and allowed to heave, to sway, and to roll. A dynamic system of the converter absorbs the wave energy through the relative movements between the floats and the links and between the adjacent links while the natural frequency of this system is approximately tuned to the frequency of the incident wave. In this way, the reflected waves and transmitted waves caused by this system are suppressed substantially since the energy of the incident wave is virtually absorbed. The wave energy converter may be provided with some air chambers and air turbines or one-directional rotating means actuated by this dynamic system so as to drive electric generators coupled thereto.

Abstract: An echo canceller for passband data signals is comprised of a pair of real passband filters which generate samples of the echo replica in response to respective streams of rotated data symbol components.

Abstract: A wind electric system intended to provide power to a power grid, for use with a wind turbine which has no starting torque. The generator is one which can function as a motor as well. When the wind is too light to permit generation, an overriding clutch mechanically disconnects the generator shaft from the turbine shaft. The clutch has also the capability of locking the generator shaft to the turbine shaft in response to a control signal. When wind speed is great enough to permit generation and the turbine is stopped, a control signal is issued locking the generator shaft to the turbine shaft. Power from the power grid causes the generator to function as a motor and accelerate the turbine to permit it to be rotated by the wind. The clutch is then returned to overriding operation and electrical generation continues until wind speed again becomes too light.

Abstract: This disclosure relates to a circuit for controlling energization of a start winding of a single-phase motor connectable by power lines to an AC power supply. The circuit includes at least two triacs connected in back-to-back series relation and connected in series with the start winding. The circuit further comprises a reed switch including reed contacts and a reed coil. The gates of the two triacs are connected across the reed contacts, and the reed coil is connected in one of the power lines and receives the line current during energization of the motor.