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: A technique is described for the preparation of stable vinyl chloride polymers wherein a vinyl chloride polymer in solution is reacted with an organotin compound. The polymer is precipitated from solution and subjected to solvent extraction, the resultant polymers evidencing a stability which is comparable with that obtained by means of the conventional prior art stabilizers.

Abstract: Parity for the address of a low order zero in an input data word is generated directly from the input data rather than from the address of the low order zero. A find low order zero circuit (11) generates an address of the low order zero in the data word. Simultaneously with this operation a parity generating circuit (12) operates on the input data word to generate parity for the low order zero address. The parity generating circuit comprises a plurality of individual circuits (30 through 33) each of which operates on a different byte of the input data word. The individual circuits each generate a control signal (E.sub.a,E.sub.b . . . ) according to whether or not its byte contains a low order order zero, and a result signal (R.sub.a,R.sub.b . . . ) which represents the parity of the address of the low order zero, if any, in the byte taking into account the byte position in the input data word. Logic circuitry combines the control and result signals to form the overall parity for the low order zero address.

Abstract: A method for forming a guard zone (21) is disclosed, suitable for a guard ring for a Schottky barrier diode or for a channel guard zone for protecting the channel inversion layer of an insulated gate field effect transistor. The method uses anisotropic (straight-line) etching of a window in a thermally grown silicon dioxide layer (2) on a silicon body (1) combined with deposition of a metallic masking layer (4, 14), such as aluminum, which is subject to a shadow effect of reduced thickness at a sidewall (25) of the window. Slight etching of the metallic masking layer results in an aperture at the resulting edges of the masking layer located in the vicinity of the sidewall of the thermally grown oxide layer. Ions are then implanted with the body through the aperture, to form the guard zone (21).

Abstract: A helical layer on a cable core produces a zero torque response when the lay angle is chosen according to the inventive method. Previously, two helical layers having opposite lay angles have been used to obtain a zero torque response. Lightguide cables having a metallic helical armor layer, for example, advantageously utilize the present technique, which reduces the tendency of the cable to kink.

Abstract: The present invention relates to a dual frequency band, dual-mode feedhorn comprising three serially connected waveguide sections (20, 22, 24) and a separate discontinuity (21, 23) at each joint between waveguide sections. More particularly, the feedhorn comprises a first waveguide section (20) for supporting the TE.sub.11 mode in both frequency bands. A first discontinuity (21) symmetrically increases the first waveguide size for converting a portion of the TE.sub.11 mode in both frequency bands into the TM.sub.11 mode. The second waveguide section (22) connected to the first discontinuity comprises an aperture size for supporting the TE.sub.11 mode in both frequency bands but only the TM.sub.11 mode of the higher frequency band. A second discontinuity (23) symmetrically increases the size of the second waveguide for converting another portion of the TE.sub.11 mode in both frequency bands into the TM.sub.11 mode.

Abstract: Polyoxide capacitors for semiconductor integrated circuits having oxide dielectric films of 500 Angstroms or less are fabricated using in-situ doped polysilicon layers to have electrical field breakdowns of from 6 to 9 MV/cm. The first polysilicon layer is formed by LPCVD using silane and phosphine at a temperature in the range from about 570 degrees C. to 595 degrees C.These capacitors are relatively precisely valued devices used particularly in applications such as filter/codecs. However, they are useful wherever integral capacitors are needed having high dielectric strength polyoxides, including such semiconductor integrated circuit devices as EPROMs and dynamic RAMs.

Abstract: A system for interpolating digital data signals to a frequency band above analog speech signals in a common transmission channel is disclosed. The system utilizes short time frequency analysis techniques to determine the cutoff frequency of the speech signal. Data signals temporarily held in storage within the system are thereafter modulated into an unused frequency band of the transmission channel above that needed for speech signals. The combined speech and data signals in the system are sent to a receiver which relays the respective speech and data signals to their appropriate locations. This system is compatible with digital signal processing techniques using Fast Fourier Transform Technology in conjunction with solid state logic elements.

Abstract: In a conventional CMOS integrated circuit such as a switched capacitor filter, power supply noise signals are coupled from the substrate to high impedance nodes via various parasitic capacitances. To minimize these noise signals and thereby improve the power supply rejection ratio of the circuit, only N-channel transistors are coupled to the nodes. Additionally, the P-tubs of these transistors are connected to an on-chip regulated power supply. Moreover, for certain metallic runners and capacitors of the circuit that are connected to the specified nodes and parasitically coupled to the substrate, grounded P-tubs are formed directly under the runners and capacitors.

Abstract: Under photoluminescence (PL) excitation, the lateral spreading of photo-excited carriers can suppress the photoluminescence signal from double heterostructure (DH) wafers containing a p-n junction. In any DH with a p-n junction in the active layer, PL is suppressed if the power of the excitation source does not exceed a threshold value. This effect can be advantageously used for a nondestructive optical determination of the top cladding layer sheet conductance as well as p-n junction misplacement, important parameters for injection lasers and LEDs.

Abstract: A dye laser (FIG. 1, 5 or 6) includes a pumping laser source (e.g. 11), an optical resonator (e.g. 13-15), and a dye solution or dye cell (e.g. 12) disposed in the path of the pumping laser light in the resonator. The dye cell disclosed herein comprises a pair of closely spaced transparent discs (21). A motor (26) serves to spin the discs at a high rate of speed. The pumping laser light in the resonator is focused on the discs at a predetermined angle (i.e. the Brewster angle). New, unbleached dye is injected axially with respect to the discs so that the spin force causes a radial flow of the dye solution between the spinning discs and, of course, past the pumping laser light spot.

Abstract: Amplifier gain is varied in response to a control voltage by a switched capacitor variable transconductance feedback network. First and second capacitors are connected in series between the input and the output of an operational amplifier. The input side of the first capacitor is switched by a first toggle switch between the input and ground. The output side of the second capacitor is switched by a second toggle switch between the output side and ground. Both toggle switches are operated by a pair of non-overlapping pulse trains. A voltage-controlled variable resistance network is connected between the common node of the capacitors and ground.

Abstract: Numerous laser transitions in the visible and near-infrared in four metal vapors (Li, Al, Ca, and Cu) have been observed in the recombination phase of the expanding plasmas produced by a segmented plasma device employing foil electrodes. Also described is a segmented vapor plasma discharge in using Ni foil electrodes.

Abstract: A toroidal, saturable core reactor (14) is connected in series with the conductors (11,19 and 13,21) of a transmission line. A termination network (16) is connected across the transmission line conductors (19,21). In response to an a.c. test signal transmitted from a generator (48) on one of the conductors (11), a series of voltage spikes are induced at the reactor (14) and superimposed on the a.c. test signal. The superimposed a.c. test signal is returned through the termination network (16) and the other line conductor (13) to a current detector (50) for detecting the spikes. A d.c. signal is then applied along with the a.c. signal. If there is a fault beyond the reactor (14), the spikes will be displaced from their expected positions. If there is a fault before reactor (14), the spikes will not be displaced. For ease in signal discrimination against noise, the d.c. signal is modulated.

Abstract: A non-inverting integrated circuit shift register stage is provided by a combination of four interconnected N-MOS transistors, connected to a two-phase clock pulse voltage source.

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: 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: The present invention relates to a rectangular corrugated waveguide or feedhorn wherein a plurality of adjacent grooves of a predetermined depth and cross-section are formed, preferably by numerical machining, in a major exposed surface of each of four plates of an electrically conductive material. The four plates are then secured together to form a rectangular corrugated passage therebetween where the ends of the line of grooves in one plate substantially meet and are aligned with the ends of corresponding grooves in another plate to form a solid line of electrically conductive material at the corners of the passage.

Abstract: With the advent of digital communications, it is common to transfer packets of information among a plurality of stations, e.g., digital computers. In order to control the transfer of the packets, various protocols have been introduced. However, the efficiency related to known multiples access digital communications system protocols tends to decrease as the digital signal rate increases. To overcome such problems, the instant communications system and protocol contemplate a communications loop having first and second oppositely directed signal paths. At least two stations are coupled to both the first and the second signal paths. A station includes an arrangement for writing a first signal on the first path and an arrangement for reading a second signal from the second path. In addition, the station includes an arrangement for reading a third signal from the first path.

Abstract: A simple, inexpensive, and reliable technique for substantially preventing the unwanted formation of a surface guiding layer during manufacture of light-guiding structures in LiNbO.sub.3 and LiTaO.sub.3 substrates is disclosed. The technique involves addition of an effective amount of a gaseous hydrogen donor to the processing atmosphere during high-temperature processing. A particularly convenient hydrogen donor is water vapor, which can be added to the atmosphere by, for instance, bubbling of the feed gas through a water column. A partial pressure of more than about 9 Torr of H.sub.2 O has been found effective in the practice of the technique.