Abstract: A warning system for rotary wing aircraft compares the accumulated altitude loss after take-off of the aircraft with its altitude above ground, and generates a warning if the altitude loss is excessive for the altitude above ground at which the aircraft is flying. The position of the landing gear, the speed of the aircraft and its altitude enable the system only during the take-off and missed approach phases of operation in order to minimize nuisance warnings during other phases. The relationship between radio altitude and altitude loss required to generate a warning is optimized for rotary wing aircaft such as helicopters.

Abstract: A radio frequency transmitter, amplitude modulated, having a single tuner that tunes the frequency oscillator, the isolating filter and the antenna impedance, all at the same time. The transmitter includes a tunable carrier generator for generating a carrier signal of a desired frequency, and a carrier isolator for filtering the carrier signal so as to ensure a clean, isolated carrier signal. A power amplifier is included for amplifying the signal from the carrier isolator. The power amplifier has a certain output impedance. An antenna is connected for transmitting the amplified signal from the power amplifier. The antenna also has a certain impedance. The transmitter further includes an impedance matching device connected between the antenna and the power amplifier for matching the antenna impedance and the power amplifier impedance. Finally, a single control knob is provided for simultaneously controlling the tunable carrier generator, the carrier isolator and the impedance matching device.

Abstract: A dome-shaped acoustic motor diaphragm having a core of aluminum foil in the form of a spider web configuration resulting in the dome shape, the diaphragm being in the form of an annular semi-dome outer diaphragm part and a dome-shaped cylindrical inner diaphragm part. The spider web core also enables a wide variety of diaphragm shapes to be possible. A voice coil bobbin is passed through a lower diaphragm layer and unto the underside of an upper diaphram layer via the core which more or less is the greatest height of the same core in the region of the outer diaphragm part, thereby resulting in a highly effective bonding strength between these parts. Damping is accomplished by means of a cylindrical bellows having a height representing the maximum excursion distance of the movable parts. A bobbin guide positioned within the bobbin and bonded to the inner face of the lower magnetic pole piece prevents the bobbin and voice coil in the annular air gap from contacting the pole pieces.

Abstract: A holder for an electret microphone of the type having a front acoustic aperture and peripheral acoustic apertures is made of insulating material and includes a first sleeve portion of a diameter to receive the microphone snugly and a second sleeve portion of larger diameter. An internal stop limits the extent to which the microphone can be inserted such that the rear portion of the microphone projects into the second sleeve portion. Through holes in the second sleeve portion provide an acoustic passage to the peripheral acoustic apertures. The internal stop is in one embodiment formed by an apertured web. In another embodiment an internal shoulder forms the stop but in that embodiment too an apertured web is provided. A concentric small cylinder extends from the web in that case and terminates short of the shoulder. In either embodiment, a rectangular plate is molded with the sleeves and this forms the cover of a microphone enclosure.

Abstract: A directional microphone operating according to the electrostatic or electrodynamic transducer principle. The pickup effect of the microphone is determined by a single phase-shifting delay line section between the rear side of the active transducer diaphragm and at least one sound entry opening provided in the microphone housing at a distance behind the plane of the diaphragm. The microphone includes at least one acoustic element coupled to the delay line section. The delay line section is arranged with the acoustic element or elements so as to have a lower limit frequency in the range of 300 Hz.

Abstract: The invention relates to a system for interconnecting memory slot machines, for example parking meters or ticket vending machines. Each slot machine (B.sub.1, B.sub.2, . . . ) includes a circuit (C.sub.1, C.sub.2, . . . ) which receives data to be transferred. These circuits are interconnected by a seizure loop (18; 20, 22) and by a data transmission loop (26, 28). When information becomes available at a slot machine, this causes the seizure circuit to be powered up, thereby supplying power to the data transfer loop and to the data-receiving circuits (C.sub.1, C.sub.2, . . . ) of the other slot machines. Once the information has been transmitted to the other slot machines, the above-mentioned circuits are no longer powered.

Abstract: An automatic utility meter reading and monitoring system comprises at each customer premises at least one sensor for automatically reading the amount of usage of a utility service, processing means for accepting data for said at least one sensor, and a communications interface connected to said microcomputer, and at a central office a main computer for accepting data relating to the amount of usage of the utility service at each customer premises over a remote link connected to said communications interface, said main computer being arranged to poll said microcomputers periodically at said customer premises on a basis to obtain therefrom billing and local management information. The continuous polling of said customer premises not only allows for easy conversion to time-of-day metering, but also provides information relating to load distribution on an ongoing basis.

Abstract: The power transmitted by an r.f. transmitting and receiving station, such as a mobile station, to a fixed base station, is controlled as a function of power received by the mobile station to obtain a constant receiving power level in the fixed station despite variations in the relative location of the stations. The power received by the mobile station is measured and sampled at predetermined instants. At each predetermined instant, the power to be received by the mobile station at a following predetermined instant is estimated as a function of the measured power, to derive an estimated power. R.f. signal power transmitted by the mobile station is reduced between the successive instants in proportion to the estimated power.

Abstract: A subscriber communication system includes a base station in a network with a plurality of subscriber stations, wherein control information is communicated between the base station and the subscriber stations over a radio control channel (RCC) at a frequency selected by the base station from a plurality of predetermined frequencies. The a base station transmits control messages including a unique network number over the RCC. Each subscriber station processes the network number in the control message received over the RCC to enable the subscriber station to process the control message in accordance with whether the subscriber station is in the same network as the base station. The timing of communications transmitted by a subscriber station over a given communication channel between a base station and the subscriber station is refined upon initial establishment of the communication channel.

Abstract: A semaphore for use in a detection system for a high voltage device and for signalling a predetermined state of the device. The semaphore comprises a housing supporting therein a retroreflector element. The housing has an aperture and the retroreflector has a reflective surface supported in a alignment with the aperture. The housing is mounted in close proximity to the device. A linkage is associated with the housing and the device and is actuated upon the occurrence of a predetermined condition whereby to expose the reflective surface in the housing for the reflection of signals through the apertures. A remote scanning device continuously generates infrared signals in the direction of the aperture and detects reflective signals from the reflective surface.

Abstract: A transmitter for repeatedly transmitting a measured value in the form of a digital signal through a two-wire transmission line, includes a receiving unit for receiving a digital command signal from a communicator through the two-wire transmission line, and a processor for sending out a response signal in response to the command signal upon reception thereof. The measured value is sent using a newest measured value after repetitive transmission of the measured value is interrupted. The measured value is transmitted from the transmitter by a change in current supplied to the two-wire transmission line, and reception of the command signal is performed by a change in interline voltage of the two-wire transmission line.

Abstract: A threshold detection circuit for improving the output of a two-wire transmitter is disclosed. The transmitter comprises a sensing means which has a sensor responsive to a parameter to be sensed by the transmitter and an excitation means which provides an excitation output to excite the sensor. A threshold detection circuit is coupled to the sensor output and provides a detector output representative of an undesired change in excitation output which can produce a sensor output not substantially representative of the sensed parameter. An output means is coupled to the sensor output and detector output and provides the transmitter output as a function of the sensor output and detector output. A distinctive transmitter output representative of an undesired change in excitation output thus detected is provided, thereby improving the transmitter output.

Abstract: The utility meter is a microprocessor-based circuit using Hall effect electric current sensors to measure power usage by residential and commercial customers. An analog signal from the Hall effect sensor is converted to a digital signal which is fed to the microprocessor for analysis and storage in random access memory. Using a real time clock, the microprocess or determines time of use information which is also stored in random access memory. The memory may be remotely interrogated via a telephone line or serial communication link. If desired, the meter can receive utility usage inputs from other utility meters, such as water, gas, etc. and to fire and intrusion alarms. To effect a submetering configuration useful in apartment complexes, institutional and manufacturing applications, a mutiplicity of meters are multiplexed to a data collection computer which is in turn networked with other data collection computers to a central billing computer.

Abstract: A utility meter reading system permits reading a meter with a noncontact shaft angle detector and simultaneous visual inspection of the dials of the meter from a laterally spaced viewing position. Each of the dials defines a patterned disc for concentric rotation with the shaft and a beveled circumferential surface which extends around the patterned disc and bears a plurality of numerical indicia. The dials are configured to be adhesively mounted over dial pointers on an existing utility meter, thus permitting retrofitting of meters with noncontact shaft angle detectors.

Abstract: Computer graphics for an industrial process installation or other computer-controlled system in which the system is graphically displayed on the screen of the computer terminal. Each controllable element in the system, such as a valve, a control dial or a switch, is marked on the display by an action point. In order for an operator to select any desired action point on the display to carry out an action appropriate thereto, a cursor is provided which can be manipulated by a key matrix to occupy a position coinciding with any action point thereon. The key matrix is a three-by-three-matrix constituted by a home key surrounded by eighty arrow keys whose arrows are directed to the major axes of a compass rose. Only one action point can be selected at a time. The selected point then effectively becomes the compass center, the previously selected point being then de-selected.

Abstract: The present invention discloses a selecting device for interfacing between a telephone line and two facsimile apparatuses and comprises a telephone line; terminal adapted to be coupled with the telephone line; two facsimile apparatus terminals adapted to be coupled with the two facsimile apparatuses respectively; a loop selection circuit coupled with the telephone line terminal and the facsimile apparatus terminals; and means, coupled with the loop selection circuit, for controlling the loop selection circuit selectively to couple two of the telephone line terminal and the facsimile apparatus terminals with each other.

Abstract: A remote sensing and communications system for installation on energized high voltage conductors is disclosed herein. The sensor modules are capable of measuring electrical, mechanical or environmental parameters in the vicinity of a high voltage conductor. The module digitizes and communicates the measured quantities via a communications subsystem mounted on and powered by an energized high voltage conductor without requiring a circuit interruption. Communications to a Central or Regional dispatch center at any desired distance from the sensing location is achieved using Ku-band or C-band spread spectrum satellite communications, or using the Geosynchronous Orbiting Environmental Satellites (GOES), or through fiber optic communications links.Individual subsystem modules are generally toroidal in shape and can be mounted on an energized high voltage conductor using a hot-stick or other means.

Abstract: The present invention relates to a device for use in an amplitude modulated RF transmitter. The device protects power transistors located in the RF transmitter particularly in the modulator and power amplifier portions of the transmitter. The device is comprised of a capacitor unit which is adpated to be charged in a first direction; a detector which detects an audio modulating signal; and a discharge unit which is connected to both the capacitor unit and the detector which selectively discharges the capacitor unit when the value of the audio modulating signal reaches a first preset level for a preset time duration during a portion of the audio modulating signal which causes positive modulation of the RF transmitter. The device also comprises a switch unit connected to the capacitor unit and which is activated when the capacitor unit discharges to a predetermined level. The switch unit is operable to remove, when activated, the audio modulating signal from the power transistors.

Abstract: A current injection compensation circuit for dynamically compensating for the effect of ambient conditions on phototransistor output is disclosed. An output voltage is maintained at a nominal reference voltage level independent of ambient light input to allow use of a large output for a detected signal. Phototransistor current is a function only of ambient conditions, especially incident ambient light and is unaffected by compensation current injection. The ambient compensation current injection network can be employed with interactive touch input devices, such as infrared touch entry systems used with video displays.

Abstract: A method and device for converting movement of an optical mouse on a surface having any random surface pattern of relatively light and dark areas separated by edges to electrical signals representing a direction of motion relative to two non-parallel axes. A plurality of prechargeable photon sensors are disposed on the mouse in a row along each axis and facing the surface periodically. The presence of an edge is periodically sensed in at least one preselected portion of each row of sensors, defining a sensor state for each axis for each period upon the sensing of an absence of an edge. Successive sensor states are compared to determine if movement has occurred relative to each axis and a signal representative of the movement determined is produced.