Abstract: A Braille mouse uses a character-code carrying member such as a disc, belt or drum to selectively raise Braille pins with a single solenoid. The Braille pins are provided with eccentric fingers which interact with a character-code carrying member, so that the character codes can be arranged in straight radial lines to allow all possible six-pin Braille symbols to be provided on a member of minimum size.

Abstract: Substantial pitch variations in artificial speech produced by dialing out a sequence of stored digital waveforms are made possible without significant distortion by varying pitch both by truncation or extension of pitch period waveforms, and by varying the dialout rate. In another aspect of the invention, pitch changes are made more natural by distributing each pitch change evenly over a large number of pitch periods during voiced phonemes.

Abstract: Artificial speech is produced with minimized memory requirements by using a bank of digital oscillators to produce voiced sounds by combining multiple harmonies of a fundamental-frequency sine wave, and using only one of these oscillators to reproduce stored nonsinusoidal waveforms for unvoiced sounds. Sufficient dynamic range is achieved with a minimum number of oscillators by generating only every other harmonic at the higher frequencies. All harmonics are derived from a single stored digitized sine wave by using stored sets of skip counts and amplitude codes corresponding to various voiced sounds to be produced.

Abstract: An inflow cannula for intraortic blood pumps has a curved, spring-loaded body for blind retrograde insertion through the aortic arch, and a soft, beveled foldable but resilient tip which properly positions the tip, if necessary, with respect to the aortic valve prior to retrograde insertion of the distal end of the cannula through the aortic valve. Auxiliary intake openings are provided in the side walls of the cannula adjacent its distal end to prevent suction from holding the tip in its collapsed state after insertion through the aortic valve.

Abstract: Improved speech sounds are produced from an all-software speech generating program on a computer which does not have a digital-to-analog converter by polling a first timer connected to the computer's speaker until a time-out is found, then applying a sample time value to a second timer so connected, and restarting the first timer. This results in the generation of a variable-duty-cycle carrier without interfering with the computer's operation. In an alternative embodiment, the first timer is used to generate an interrupt at regular intervals, and a sample time value from a storage buffer is then applied to the second timer.

Abstract: The reliability and compactness of a percutaneously insertable intravascular axial flow blood pump are improved by connecting the pump's rotor and drive cable through a resiliently extendable rotor extension. The rotor extension and drive cable fitting are so designed that the thrust bearing surfaces of the purge seal and cable fitting can be preloaded by strongly pulling the cable fitting against the resiliency of the rotor extension to move one of the bearings away from the other, then relaxing it to a predetermined preload, and finally immobilizing the bearing in the position corresponding to that preload.

Abstract: 4800 B/S full duplex operation of a frequency-multiplexing modem over the switched telephone network without cancellation is made possible by combining 900-baud, 32-state operation with a combination of analog filtering and raised cosine digital filtering and stop bit robbing.

Abstract: An implantable ventricular assist system uses a small high-speed axial flow blood pump which may be grafted into the patient's circulatory system. The pump includes a blood tube in which the pump rotor and stator are coaxially contained, and a motor stator surrounding the blood duct. A permanent magnet motor rotor is integral with the pump rotor. Purge fluid for the hydrodynamic bearings of the device and power for the motor are preferably percutaneously introduced from extracorporeal sources worn by the patient. The purge fluid is introduced into the pump stator blades. This construction avoids the creation of discontinuities in the blood path wall due to the routing of drive power and/or fluid supply elements through the blood path wall. The described construction greatly reduces the size of the implant needed for a given blood flow rate and enhances its physiological compatibility with the body.

Abstract: A high-frequency transvalvular blood pump for temporary cardiac assist provides suction to decompress the ventricular cavity during both systole and diastole. The intake end of the pump is connected to a cannula which is inserted into the ventricular cavity through the aortic valve, and which has an intake opening at its distal end. The intake and outflow ends of the pump are closed, respectively, by one-way valves which allow blood flow only in the direction of body perfusion. The pump itself consists of a stiff barrel whose interior volume can be alternately reduced and expanded by a flexible membrane controlled by pneumatic or hydraulic pressure from an extracorporeal location through a percutaneously inserted lumen.

Abstract: A disposable, sterilizable cable drive unit for an intravascular blood pump includes a rotor enclosed in a fluid-tight enclosure which can be slipped into the stator of a drive motor. The unit is connectable to a constant-rate purge fluid supply and to a dual-lumen cable sheath. One lumen provides a sterile purge fluid path; the other carries the drive cable to the blood pump and provides a return path for a flushing fluid in which the cable is immersed. The flushing unit is derived from the purge fluid supply at a constant rate, and the rotor may also be immersed in it if desired. The unit is held in the drive motor by a manually operated detent, and the self-centering action of the rotor aligns it with the stator when the motor is energized. The motor is mounted on a gimbal so as to be alignable with the cable sheath at its point of insertion into the patient's vascular system, in order to prevent stresses on the patient and kinks in the cable sheath.

Abstract: A system for controlling a gate includes a microprocessor which normally automatically recloses a gate after it has been opened in response to a radio or sensor loop signal, and which normally locks the gate against movement when the gate motor is stopped. When an obstruction is sensed in the path of the gate, the automatic reclosing feature and the sensor loops are disabled, the gate drive remains unlocked even though the motor is stopped, and the response of the system to a radio signal is changed to produce alternating opening and closing of the gate on successive radio signals. At all times, the gate drive lock is released before the motor is started and is not engaged until after the gate has come to rest.

Abstract: Turbulent-flow emitter channel sections are vacuum-formed in an extruded flat plastic strip. The strip is then applied to a hose substrate, and inlet and outlet openings are formed at opposite ends of the channel sections. The strip may be hot-melt bonded to the substrate during a co-extrusion process, or it may be applied to the hose substrate in a separate operation. Flow rates are easily controlled without changing the structure of the strip by varying the number of channel sections in which outlet openings are formed.

Abstract: Substantially continuous fluid delivery in a variable-speed peristaltic pump is achieved by operating the pump at maximum speed through most of the deadband regardless of the delivery rate. Safety means are disclosed to monitor the correct operation of the speed control.

Abstract: A copy protection system for computer discs in which a key sequence of 1101 in a copy protection section of the program is deliberately rendered ambiguous by repeatedly recording a word containing that sequence while gradually shifting the phase of the transition forming the central "1" of the sequence until the sequence becomes 1011. When this series of words is repetitively read, successive reads will be inconsistent with one another. The gradual phase shift cannot be reproduced if the disc is copied on a standard personal computer, so that the inconsistency on successive readouts will not be present in a copied disc. The program is so designed that it cannot run unless inconsistencies are detected in the copy protection section of the program. The provision of "1"s on each side of the central, variable two-bit sequence prevents spurious loss of synchronization on the copied disc which could be interpreted as an inconsistency.

Abstract: A miniature high-speed intravascular blood pump is formed as a single stage with two rows of rotor blades and a single row of stator blades within a tubular housing. The rotor's first row produces a mixed centrifugal and axial flow, while the rotor's second row produces a purely axial flow. The blades of the second row are shaped so as to produce a uniform blood flow along the trailing edges of the blades. For this purpose, the bases of the outer trailing edges of the second row blades have a negative propulsion angle. The pump has a purge-sealed hydrostatic bearing which is spring-loaded for minimum gap. The pump is driven by a cable encased in a dual-lumen, fluid-filled cable sheath formed of a coextrusion of a soft, blood-compatible outer layer and a stiff, abrasion-resistant inner layer. The cable sheath serves both as a purge fluid supply for the bearing, and as a means for flushing abraded debris away from the pump.

Abstract: Topological information of the cornea and anterior chamber of an eye is optically developed by projecting toward said eye a target image sharply focused in a movable flat plane. As the plane is moved through the eye, the reflection of the target is in focus first at the center and then at increasingly radially outward locations. The reflection is detected and clipped to delete all image portions which are out of focus. As the image plane is moved through the eye, the clipped reflection traces the topology of the eye. This information can be fed into a computer and used to compute appropriate topological displays. Such computations can readily be made insensitive to any eye movement during the measuring process.