Abstract: An integrated circuit amplifier for a high impedance microphone (100) of the capacitance type is disclosed. The subject amplifier circuit permits the further miniaturization of an electret microphone as it is capable of providing an input impedance simulating a resistor value of hundreds of megohms. The circuit particularly comprises duplicate coupling circuits (101a and 101b), a source of reference direct current voltage (103), and a gain providing circuit (102). The coupling circuits (101a and 101b) comprise a first pair of diodes (Q1 and Q2) symetrically placed about one input terminal (IN1) of the microphone (100). Outputs of the reference voltage source (103) are provided to coupling circuits (101a and 101b) and through the coupling circuits to gain providing circuit 102. Such an arrangement facilitates power supply noise rejection and automatic canceling of direct current voltage drifts. A current repeater circuit (FIG.

Abstract: A video signal actuated switch is disclosed having general application in the area of video home entertainment systems. The present video signal actuated switch comprises an impedance matching circuit (200) for matching the impedance of an incoming video signal (VS) for display. A high impedance amplifier (201), having an associated filtering circuit (201a), amplifies a particular band of frequencies comprising a known component frequency of the video signal (VS). No significant degradation of the standard video signal results from the application of the impedance matching circuit (200) in combination with the amplifier circuit (201). An actuator circuit (202) provides a signal (F) responsive to the output of the amplifier circuit (201) to a control circuit (203). The control circuit (203), responsive to signal (F), provides a control signal (E) for controlling the selection of video inputs to a video terminal (100) and for controlling or powering an RF modulator circuit (206).

Abstract: A maskless process is disclosed for applying a patterned solder mask coating to a circuit board (31). In accordance with the process, there is applied to the surface (30) of the circuit board an uncured material (32) having a cure reaction which is susceptible to inhibition by the presence of oxygen. The surface of the circuit board is covered with the material to a first predetermined thickness. This first predetermined thickness of material on land areas (34) surrounding holes (36) in the circuit board is diminished to a second predetermined thickness by allowing a portion of the material on the land areas to flow into the holes. The uncured material is exposed to a first energy source which delivers a quantity of energy such that a surface layer (38) having the second predetermined thickness has its cure reaction substantially inhibited due to the presence of oxygen.

Abstract: The present key telephone system comprises cordless telephone stations (FIGS. 6 and 7) which communicate over a line-of-sight transmission end link (276 or 277). The system further comprises a central controller (101) for switching communications between the cordless stations and to the message network. The central controller does not provide any station to transmission channel concentration. Concentration occurs in the bidding by a cordless station for access to a channel provided by the line-of-sight transmission end link. A particular number of transmission channels are provided by the line-of-sight end link which are bid for by any practical number of cordless stations. Subsystem controllers (104) are provided in a large cordless key telephone system. The subsystem controller reformats data for transmission between the central controller (101) and a cordless station.

Abstract: An electrical wire handling tool (10) is disclosed. This tool is useful for cutting jumper wires to any required length and at any location, for installing jumper wires into slotted beam connectors, and for removing no longer needed jumper wires from such connectors. The tool is comprised of a handle (20) which has first and second recesses (23,27 and 25,29) in oppositely disposed ends (24,28 and 26,30). In the first handle recess there is affixed means (40) for coupling electrical wires to the connectors. In the second handle recess there is affixed means (60) for removing electrical wires from connectors. The tool further includes a third recess (32) in an intermediate, internal region (31) of the handle which has housed therein means (80) for cutting electrical wires.

Abstract: A tool for stripping insulation from coaxial or multiple conductor cables is disclosed. The tool consists of a support assembly (1) with an integrally connected spring (5) which swivels between an up and down position. The support assembly (1) contains a channel (2) which runs along its length where the spring (5) rests in its down position. A semicircular slot (4) receives the insulated cable. Embedded within support assembly (1) is a knife blade (7), a portion of which is exposed in the slot (4). The knife blade penetrates the insulation when the spring (5) is in its down position causing an incision through the insulation. A ring is placed at one end of the tool in which the user can insert a finger and thereby twirl the tool around to effect relative rotation of the tool and cable to cut through the cable over its entire circumference.

Abstract: An electromagnetic transducer is disclosed that includes a pole assembly (110) comprising a central pole piece (112) upstanding from a back plate (114). A coil assembly (120) is disposed about the central pole piece (112) and rests on the back plate (114). In addition, an inverted cup-shaped permanent magnet (130) having a central opening (132) in its base (131) is positioned so that the wall (134) of the magnet circumscribes the coil assembly (120) and rests on the back plate (114). The rim of the central opening (132) in the base (131) of the permanent magnet (130) is spaced from and encircles the upper end of the central pole piece (112). Also the wall (134) of the permanent magnet (130) is of a height that the upper surface of the base (131) lies in essentially the same plane as the upper surface of the pole piece (112). A central armature (222) is supported by a nonmagnetic diaphragm (221) so as to be positioned above and spaced from the central pole piece (112).

Abstract: The present terminal independent color memory for a digital image display system provides for inter-system compatability, color display systems generally having varying modes of access to color memories, varying color memory capacities, and features such as blinking implemented in varying ways. The data processor (1) of the present system may access color memory (6a) of video controller (6) or color values stored in permanent memory (9) or random access memory (10), responsive to the same command language. The present data processor (1) is also capable of entering color data values comprising color hues and gray levels into color memory for use in a terminal independent manner. Multiple process chained blinking from a particular color to a particular color is also provided by the present processor, the several processes in time-delayed relationship to one another.

Abstract: A method and apparatus, comprising a video data bus (8), a plurality of video memory modules (VM1-VMN), and bus arbitration circuits (BAC1-BACN) associated with each video memory module, are disclosed for compiling digital image information for display. A data processor (1) addresses the plurality of video memory modules over a processor data bus (2), the data processor for assigning a priority value to picture element data stored in the video memory modules. Upon command of the data processor, a frame (5 to 300) of picture element data is serially compiled on the video data bus (8). Data contention between video memory modules for access to the video data bus is controlled by the bus arbitration circuits, the picture element data bidding with the highest priority value gaining access. In one embodiment, the priority value represents the depth of a point of a solid object for display and/or the relative depth of picture element data comprising the object for display.

Abstract: A fiber-optic electronic connector assembly provides for consistent low insertion loss operation by providing for the fiber optic connector assembly to float as a unit in three substantially orthogonal directions.