Abstract: An FSK modem for coupling a standard data port (50) to a telephone line (45) in which the signal path between the phone line and the data port passes through a processor (55). The same frequency detection apparatus (83, 192, 180) is used to both demodulate FSK encoded signals and detect the presence of a telephone ringing signal on the line. A pair of impedances (161, 162) provide alternate paths either through an input filtering network (167) or bypassing the network (135, 69) in a manner which allows the ring signals to pass directly to the input (69) of the frequency detector while assuring that only filtered FSK signals reach the input. Also shown is the use of the same frequency synthesizing apparatus (86, 253, 259) for generating FSK output signals and high group DTMF signals with appropriate switchable attenuation (88) provided in this signal path.

Abstract: An overvoltage protection arrangement for preventing the occurrence of breakdown of a subscriber line control stage, independent of its structure and the integration technology used, by providing short-circuiting diodes in the control stage to prevent the occurrence of the overvoltage and providing voltage-limiting elements in those positions where overvoltage charge must be drained.

Abstract: A resistor and diode means are electrically connected in series between nodes A and B on the base electrodes of first and second transistors of a differential amplifier. These nodes A & B are also connected to a source of temperature-compensated load-sensitive reference voltage and to a tap point, respectively, that senses current in the loop of a carrier-serviced subscriber's telephone set. The base and emitter of a control transistor are also connected to associated nodes A and B. Conduction of the diode means and control transistor prebiases the latter and reduces the reference voltage during an on-hook condition. When the handset goes off-hook, the node B voltage rises faster than that on node A for decreasing the conduction rate of the control transistor to indicate an off-hook condition, and eventually cutting off the control transistor prior to the diode means. This operation of the diode means extends the loop length over which the circuit will detect an off-hook condition.

Abstract: An electrical controller, such as a controller timer for a home lighting circut, is connected so that a power switch like a triac controlled thereby replaces a conventional toggle switch operating in conjunction with another toggle switch in series therewith which can operate the controller. The timer is continuously coupled to the AC power system by permanent connections between the movable pole of the remaining toggle switch station and the load terminal of the triac of the controller and the power system. A stationary contact of the switch forms a control signal terminal which extends to a control input terminal of the controller. The controller may also include a depressible pushbutton or other on-off control switch which when successively operated generates pulses which toggle a control circuit to alternately render the triac conductive and non-conductive, and to program a controller-timer.

Abstract: A control system controls the movement and position of an automated device as it moves along a movement track. The control system comprises a chart extending stationarily transversely adjacent along an operative portion of the movement track which includes a light reflective code uniquely defining each increment of length of the chart. A light source is carried by the movement device for illuminating the chart and creating the reflected optical signals. A camera device is also carried by the movement device and receives the optical signals. Corresponding electrical signals are derived and are utilized by a computer processor to control the position and movement of the movement device. The chart includes a plurality of parallel bars extending along the length of the chart. A portion of the bars define, in binary code, the unique optical signal reflected from each distance increment along the chart. A remaining portion of the bars assure the integrity of the reflected optical signal.

Abstract: A piezoelectric loudspeaker thin plate-like shaped and using a piezoelectric ceramic plate for a sound-generating portion, which comprises a disc-shaped diaphragm formed of a metallic plate, a disc-shaped film using a material of a smaller Q-factor and formed about equal in diameter to the disc-shaped diaphragm, and a disc-shaped piezoelectric ceramic plate smaller in diameter than the disc-shaped diaphragm, these three members being stuck concentrically with each other, so that the integral-stuck member is supported at its outer peripheral portion to a frame.

Abstract: A control device for a stepping motor provided with a coil and a rotor performing a rotary movement when a current passes through the coil, comprising means for producing a plurality of time base signals, means for producing pulses for controlling the motor in response to said time base signals, means responsive to the control pulses for supplying the motor while maintaining the current in the coil at a substantially constant and given value. The device also comprises means for analyzing the voltage signal present on the coil or a signal which is representative thereof, and for supplying data concerning the voltage induced in the coil by the rotor movement.

Abstract: A loudspeaker enclosure has a loudspeaker driver mounted on a surface of the enclosure such that the driver has an exposed front face to produce sound waves which are sought to be transmitted to a listening space exterior of the loudspeaker enclosure. A plurality of successive spaced limp or semi-limp non-porous pliable barriers are positioned in an opening between the interior and exterior spaces of the enclosure so as to relieve rear pressure of the loudspeaker driver while attenuating the rear sound waves and providing a damping effect on the loudspeaker driver.

Abstract: There is disclosed a method and a control system for synchronizing the frequency of electrical current produced by a generator with the frequency of electrical current in an electric power grid so that the output of the generator can be provided to the grid. The generator is driven by an expansion turbine which utilizes hot pressurized gas from a process in which the pressure must be maintained constant.

Abstract: A remote volume control apparatus for audio equipment is operated by the ringing of a telephone to slowly decrease the volume of an audio amplifier during the control's initial operation, maintain the volume at a preselected low volume and slowly increase the volume automatically after the termination of the telephone conversation. In the preferred embodiment, a circuit active indicator also is provided for indicating both proper apparatus operation an activation of the telelphone signal. An attenuation level control also is provided in the form of a switch selector operable to enable the user to preselect a desired attenuation level.

Abstract: A reverberation apparatus is formed of bucket brigade delay circuit having its input connected to a signal source. An output of the delay circuit is connected through a spring-type reverberator to one of two inputs of an adder, the other being connected to the signal input. The output of the adder provides the desired reverberation sound. In one embodiment, two series connected delay circuits and reverberators are provided, each connecting to a respective input of a respective adder. The other inputs of each adder are connected to the signal source and the outputs of the respective adders provide separate stereophonic-like left and right channel outputs.

Abstract: A protective cover is disclosed for the push button array of a push button dial telephone set. The cover comprises a flexible elastomeric sheet having a grid of upwardly-directed pockets, the lower-facing ends of which are open for snugly receiving and thereby overlying the corresponding array of push buttons on said telephone set. The pockets are elastically depressible independently of one another toward their open ends to permit individual displacement of the underlying telephone set push buttons received in the pockets. The sheet includes a skirt portion extending laterally beyond the grid and the sheet is continuous between its lateral edges whereby the entire push button array is overlaid by the cover and thereby protected against spilled liquids or other environmental hazards. The outwardly facing parts of the pocket portions carry readable indicia thereupon corresponding to the indicia on the underlying push buttons.

Abstract: A card reading assembly includes a drive for driving a card carrying recordings on one or more entry regions thereon along the course of travel typically due to the force of gravity on the card. A plurality of stops force the card to a temporary stop during the course of its travel and a pickup head disposed in the course of travel of said card scans said entry regions of the card arrested by the stops for reading the recordings on the entry regions.

Abstract: The variation of the load on a wind-driven A.C. generator (16) in accordance with a predetermined law which relates the load to the speed of rotation, is achieved by detecting the period of each half cycle with the aid of a timing unit (10), calculating the percentage conduction required in each half cycle in accordance with the predetermined mathematical law, and using the calculated result to gate a pair of thyristors (12, 14) to conduct for said calculated percentage in alternate half cycles so as to pass a unidirectional current to said load. By variation of conduction during each half cycle the effective resistance of the load can be matched to the voltage output of the A.C. generator over a wide range of speeds. Not only can the efficiency of the system be increased, but the windmill is prevented from being stalled in light breezes.

Abstract: A plurality of nodes of split vibration of a diaphragm are driven by a plurality of voice coils to prevent split vibration of the diaphragm. The voice coils are inserted between three or more layers of magnetic poles respectively and driven by a magnetic circuit including a plurality of magnets magnetized in the same direction as the vibration of the voice coils.

Abstract: A telephone security system particularly for use with cordless telephone, operates to prevent the base station of the system from being accessed by an unauthorized user.Preselected digits are set by means of switches. In order to receive a dial tone, the correct digits as selected by the switches must be dialed. The security system operates to compare the dialed digits with those digits set by the switches. If a favorable comparison is had, the security device then connects the telephone line to the base station and allows dial tone to be transmitted to thereby enable a call to be implemented by the user.

Abstract: A microphone unit particularly suitable for conference applications is provided, wherein an acousto-electric transducer is disposed between two dish-like back-to-back sound collectors, each having a central aperture exposing one side of the transducer, which preferably has a single planar diaphragm.

Abstract: A method of sequentially moving a stepper through a plurality of positions (steps) and current states associated with each of these positions from an initial step to a final step. When the direction of sequential movement is in a first direction, the number of steps is incremented before the current state associated with the final step is reapplied to the stepper motor. In a preferred embodiment, a shortened period of time is allowed immediately before the current state associated with the final step is applied to the stepper motor. The method diminishes the magnetic hysteresis by always electrically and magnetically approaching the final position (step) from the same direction whether or not the stepper motor physically approaches the final position from the same direction.

Abstract: A circuit arrangement for connecting a communications set to a subscriber line of a subscription communication network in which each subscriber line includes two wires between which the communications set is conductively connected, which arrangement includes an operational amplifier having a noninverting input, an inverting input and an output, a setting transistor connected to have its conductive state controlled by the signal at the amplifier output and connected for influencing the current flowing between the two wires of the associated line and to the communications set, and circuit elements connected for applying to the amplifier inputs respective voltages proportional to the voltage between the two wires of the associated line and proportional to the current flowing between the two wires of the associated line and to the communications set.

Abstract: A gasket is disclosed for use in effectively sealing to communications equipment, a protective cover for a key-actuated switching array which projects through a generally planar surface on the equipment. The protective cover is of the type comprising a flexible elastomeric sheet having one or more recessed pockets adapted to overlie and receive the array of key-actuated switches, whereby each of switches is independently depressible through the sheet. The sheet includes a skirt-like border portion extending laterally beyond the pockets, and the sheet is continuous between its lateral edges, whereby the key switch array may be overlaid by the one or more pockets, with the skirt-like border portion contacting the planar surface beyond the array. The array is thereby protected from spillage of liquids or the like. The gasket is adapted to extend completely around the periphery of the sheet in overlying relation to the border portion.