Abstract: An ionization smoke and fire detector comprises a molded plastic housing that includes a nodal ring for supporting a vibrating plate that is part of an alarm. The alarm may be driven by piezoelectricity or by an electromechanical device. If the detector is battery powered, a portion of the housing is cut out to permit removal and insertion of a battery holder that makes contact automatically upon insertion to supply electric power to the electronic circuit of the smoke detector. One electrode of a reference chamber for the smoke detector is formed by wave-soldering an open metallized area on the printed-circuit board. Contact with the movable element of the alarm and with a high-impedance input in an integrated circuit are made through springs that are not soldered or welded.

Abstract: An automatic reorder and alarm system for use with residential fuel-oil tanks which sends reorder and alarm data to a central station over the direct-dial telephone network when the fuel-oil level in the tank falls below a predetermined value or when an alarm situation, such as low temperature, occurs at the tank location. An inexpensive sensor/sending unit located at each customer tank includes a simple sensor which mounts on either the tank or an existing fuel-oil level gauge, a microcontroller circuit and a modem circuit. The microcontroller circuit uses a simple low-stability oscillator as a reference for internal operations and for modem transmission frequencies. Because the oscillator frequency cannot be precisely determined due to component tolerances and has a substantial amount of drift, a special data transmission format is used for data transmission over the telephone lines between the microcontroller and the central station.

Abstract: An electronic lock system for a two-way radio. The radio is locked by entering a security code. While locked, the keypad is disabled and cannot be used. In order to unlock the keypad, the proper three-digit code must be entered. If an improper code is entered, the radio automatically transmits a message to indicate the identity of the radio and that an improper code has been entered.

Abstract: A two-wire transmitter having a detecting section for detecting a physical variable to be measured to produce a detection output, first and second constant voltage devices connected in series with a two-wire transmission path, a signal processor driven by a voltage supplied by the first constant voltage device for converting the detection output into representative serial pulse signals and a switching circuit which is connected in parallel with the second constant voltage device and is turned on and off by the serial pulse signals to produce corresponding output signals from the transmitter on the two-wire transmission path by utilizing a current flowing in the two-wire transmission path while enabling the transmitter to connect in a single loop with another two-wire transmitter.

Abstract: A movement parameter sensor for sensing of parameters of movement between a stator member defining a frame of reference and a rotor member movable relative to the stationary member about a rotation axis. The sensor includes field providing means for generating an electric field located at the stator member, the field providing means including a pole arrangement comprising an array of four source electrode means arranged adjacent to each other along a field line around the rotation axis. The field providing means includes an excitation signal generator for generating four equal frequency excitation signals at 90 degree increments of phase, each one of the four excitation signals being applied to a respective one of the four source electrode means such that a virtually moving electric field is created at the source electrode means so that the electric field effectively moves relative to the stator member along the field line.

Abstract: A system is disclosed for transmitting a sensed temperature from a transmitter to a remote receiver over a modulated carrier through the atmosphere. The transmitter and the receiver are battery powered and include timing circuitry having low power consumption. The transmitter and the receiver are both cyclically turned on for a relatively short period and off for a relative long period with the receiver's on cycle being synchronized with the occurrence of the transmission of the modulated carrier. The receiver further employs techniques to minimize the effect of noise on the reception of the transmitted data which can occur from extraneous signal sources broadcasting in the same frequency band or from environmental noise.

Abstract: An electromagnetic transducer is disclosed wherein separate elongated strips of magnetic material are secured on both sides of a plane containing a flat flexible insulating thin-film diaphragm. Conductors attached to the diaphram extend primarily parallel to the magnetic strips and cause movement of the diaphram when excited electrically. The conductors can also deliver current induced by diaphram movement within the field. The magnetic strips are fastened to a frame that clamps the perimeter of the diaphram. The sub-assemblies containing the magnetic strips provide maximum available area for the propagation of acoustic waves to and from the environment and provide increased flux density.

Abstract: A speaker transducer assembly is disclosed which includes first and second speaker diaphragms supported on a frame in over and under juxtaposition. Each of the speaker diaphragms has a central opening defining an inner periphery which is attached to a voice coil form for coaxial movement therewith and in unison. An intermediate baffle is coaxially positioned between the speaker diaphragms to define upper and lower, separately vented chambers. The upper chamber is vented through an outlet in the region of the outer peripheries of the first speaker diaphragm and the intermediate baffle; similarly, the lower chamber is vented through an outlet situated in the region of the outer peripheries of the second speaker diaphragm and the intermediate baffle. Preferably, the two vent systems have different vent exhaust areas to obtain stagger tuning and thus achieve a split of the deepest frequency load.

Abstract: A chordic keyboard including chordic data entry locations corresponding to the five fingers of the human hand and correlation apparatus for correlating a set of chordic data entry location engagement combinations to a set of letters in accordance with a code which is characterized in that available data entry location engagement combinations are arranged in a plurality of groups, the engagement combinations in each group having a predetermined relationship among their fingering patterns, each group being matched with letters forming a recognizable combination of letters, whereby the fingering patterns are readily memorizable.

Abstract: An apparatus for visually indicating abnormal phase relationships between incoming or outgoing phases for a plural phase device, comprised of a plurality of light emitting means interconnected between phases by a logic circuit arrangement whereby the various combinations of on/off indicators present a coded, visual presentation representing the specific mismatch condition of the network. The invention encompasses the concept of incorporating the indicating circuitry within the multiple phase device enclosure and providing an aperture in the enclosure so that the indicators may be viewed without the necessity of gaining access to the interior of the device and exposing individuals to the danger of high voltage/current circuits.

Abstract: A communication apparatus inserted in parallel in a two-wire communication line of a two-wire measuring instrument which consists of a transmitter and a receiver connected to each other through the two-wire communication line and transmits a process value detected by the transmitter to the receiver as an analog signal, the communication apparatus being adapted to communicate with the transmitter, comprising a switching device for separating a closed loop constituted by the transmitter and the receiver into a first loop including the transmitter and a second loop including the receiver, a power source for supplying power to the transmitter in the first loop, and dummy output means for outputtting a dummy signal to the receiver in the second loop.

Abstract: A manually operable touch pad for generating steering signals and enable signals for manipulating an image on a CRT display or for controlling the operation of plural motors whereby the image or object being driven can be positioned using appropriate hand/eye coordination. The touch pad comprises a box-like mounting base supporting a rectangular printed circuit board on which are mounted four opto-switches centered on the respective edges thereof. The printed circuit board also supports other circuit components and the necessary interconnecting conductors. Overlaying the base in covering relation with respect to the printed circuit board is a molded plastic top having a center post which depends downwardly from the underside thereof, passing through an apertrue in the printed circuit card and adaptive to be secured to the center of the base by a flexible coupling.

Abstract: An electrical transducer comprising a magnet system (1), a diaphragm (5) and a voice-coil device (3, 4), coupled to the diaphragm. The voice coil (3) is situated in an air gap (2) of the magnet system and the magnet system is coupled to a chassis (7). The chassis is provided with a connection unit (10) having at least two coupling means (11, 14) each comprising a first terminal (12 and 15 respectively) for receiving an electric signal and a second terminal (13 and 16 respectively) electrically coupled to said first terminal. Each second terminal is electrically coupled to an electrical connection (20 and 21, respectively) of the voice coil via a lead (18 and 19 respectively). The leads (18, 19) are provided with a spacer (22) made of an electrically non-conductive material, for example, a plastic material (FIG. 2a).

Abstract: The invention is primarily directed to sensor modules for mounting directly upon energized electrical power lines to monitor parameters associated with operation thereof, wherein the modules have a more compact lateral configuration than prior art modules designed for the same purpose. The modules include a first, cylindrical housing portion containing the sensing means and other electronic data processing and transmitting elements, and a second housing portion, affixed to the exterior of the first portion and extending not more than about 150.degree. around the periphery thereof, and enclosing mechanical elements of the module mounting means.

Abstract: The present invention relates to a keyboard button structure. Each button has a pair of side mounted "U" shaped plates. Holes are provided in the housing panel and protrusions are formed inside the holes to permit rapid assembly of the button into the holes, and to prevent loss of buttons. A rubber member between the button and the panel provides button return and also permits feel of the contact and comfortable operation. The invention's novel structure provides economic and other advantages.

Abstract: The invention relates to a wide-band loudspeaker in which the overall diaphragm is divided into an inner and an outer diaphragm sub-area. The inner diaphragm sub-area preferably consists of a dome-shaped cover of the moving-coil support. The outer diaphragm sub-area can be formed as a cone or NAWI diaphragm or as a shaped or moulded body, the shaped body having an at least approximately planar front face and its rear boundary face having the form of a cone or NAWI diaphragm. The outer diaphragm sub-area is connected to the moving-coil support by a frequency-dependent yieldable connection with high damping which at high audiofrequencies practically decouples the outer diaphragm sub-area from the moving-coil support but at low audiofrequencies acts like a rigid connection.

Abstract: Cycle stop-light equipment having a deformable member which is squashed upon operation of the hand-brake lever to operate an electrical switch to illuminate the stop-light.

Abstract: A switching device operable to monitor for the presence of an audio signal on a primary input line to a mixer includes a retriggerable timer responsive to activity on the primary line. When activity ceases for a predetermined time interval, the retriggerable timer connects to the mixer a substitute program, for example background music to be played through a different mixer input channel during performers' break. The switching device is operable for professional-type balanced low impedence audio systems wherein the mixer impresses a DC bias on the signal line to power condensor microphones. The microphones remain operational whether or not the substitute program is enabled. Upon resumption of microphone activity on the primary line, the switching device is automatically reset.

Abstract: An intermittently driven transmitter having high power output which is driven intermittently so as to transmit a signal via, for example, a satellite in which the voltage supplied to the transmitter is boosted and supplied to a capacitor. When the signal is to be transmitted, the voltage stored on the capacitor is supplied to a constant voltage circuit which generates a constant voltage which is higher than the voltage supplied to the transmitter and which is supplied to a power amplifier in the final stage of the transmitter and, thus, the intermittent type transmitter with a suitable battery drive system is obtained.

Abstract: An industrial process control transmitter has a modular construction, with a detector module and an output module electrically connected together by a serial bus. The output module includes a microcomputer, a modem for digital communication over the two-wire loop, analog output circuitry for controlling loop current, a digital-to-analog converter, and a memory for storing calibration factors and D/A characterization factors.The detector module includes several sensors with associated circuitry to convert the sensor signals to digital signals. The detector module also includes a memory which contains characterization factors unique to the sensors which can be used by the microcomputer to correct the digital values provided by the detector circuitry. The microcomputer of the output module is considered the master unit, and all of the circuits of the detector board which interface with the serial bus are considered slave units.