Abstract: An integrated circuit photodetector includes a transimpedance amplifier including a differential amplifier stage with PNP emitter-coupled transistors and a PNP input transistor which are biased only by base currents of the emitter-coupled transistors, to achieve low input bias current. Low noise operation is achieved by bypass capacitors coupled between the bases and emitters of the input transistors, respectively. A constant current source supplies a current which develops a small pedestal voltage across a resistor to bias the non-inverting input of the transimpedance amplifier so as to avoid nonlinear amplification of low level light signals. A positively biased N-type guard tub surrounds the photodetector, which is formed in a junction-isolated N region on a P substrate, to collect electrons generated in the substrate by deep-penetrating IR light to prevent them from causing amplification errors.

Abstract: A push-pull output circuit includes first and second transistors each having a base coupled to a first conductor coupled to respond to an input signal. An emitter of the first transistor is coupled by a first resistor to a first supply voltage conductor and an emitter of the second transistor is coupled to the first supply voltage conductor. A pull-up circuit is coupled to the collectors of the first and second transistors. An output conductor is coupled to the collector of the second transistor. A third transistor having an emitter connected to the collector of the first transistor and a base and collector of a fourth transistor. A bias current source is coupled to the base of the third and fourth transistors to maintain the collector of the first transistor and the output conductor at substantially equal voltages.

Abstract: An automatic guitar string tuning device includes a foot-operated switch for controlling an electrical solenoid which rotates a cam shaft mounted upon a guitar or other stringed instrument. The solenoid rotates the cam shaft between first and second positions under the control of the foot switch. Several of the guitar strings are secured to tensioning arms which engage corresponding camming surfaces formed upon the rotating shaft. Rotation of the cam shaft between the first and second positions causes movement of the tensioning arms and thereby changes the pitch of the strings attached thereto.

Abstract: A system discriminates an in-focus image from an out-off-focus image so as to reduce both systematic and statistical errors in a measurement of the in-focus image. The system produces a probe beam and a reference beam from a point source, and antisymmetric spatial properties are produced in the reference beam. An in-focus return probe beam is produced as a result of directing a probe beam into an in-focus image point, and antisymmetric spatial properties are produced in the in-focus return probe beam. The reference beam is interfered with a beam from an out-of-focus image point, and the reference beam is interfered with the in-focus return probe beam. The reference beam is detected by a single-pixel detector as a square of an amplitude of the reference beam, and the in-focus return probe beam is detected by the detector as an interference term between a return reference beam and the in-focus return probe beam.

Abstract: An audio power amplifier module fits in a disk bay of a computer and bolts to the frame of the computer. The module is powered from the power supply in the computer and uses the frame of the computer as a heat sink. The module includes connectors for attachment to an internal sound board and to external speakers. A volume control is provided on the power module, in addition to the volume control typically included in a sound board.

Abstract: A security grate is disposed intermediate a conventional multi-apertured vent on the front of a garage door panel to prevent intrusion through the juxtaposed aperture in the panel. A backing plate may be located on the interior of the panel to further hinder unwanted removal of the vent and the security grate fasteners from the panel to obtain access to the aperture in the panel. Alternatively, the security grate may be disposed adjacent the interior of the panel and then the backing plate may be omitted. A cover of insulating material is attachable adjacent the rear of the panel to prevent air flow through the panel aperture and to provide insulation. A transparent or translucent cover may be substituted for the insulating cover to provide illumination when the garage door is closed. A closeable opening may be provided in the cover to permit airflow therethrough on a selected basis.

Abstract: An infrasonic frequency resonant circuit and method for use thereof. An electric power distribution system is employed both as antenna for ISF signals and as a source of inductive reactance for a resonant circuit tuned to a band within the ISF spectrum. A capacitor is placed from the neutral conductor to the ground conductor at an ac power outlet in a structure to form a resonant circuit ordinarily tuned to a band within the ISF spectrum. An ISF spectrum analyzer is connected to the neutral and ground terminals of the resonant circuit to visualize ISF electromagnetic signals induced on the electric power distribution system in both the frequency domain and the time domain and so as to be more readily evaluated.

Abstract: A column-driver integrated circuit, and related method, for driving the columns of LCD displays uses paired digital-to-analog converters to provide analog signals in an upper voltage range and in a lower voltage range. During a first drive cycle, first and second digital data words are provided to the first and second digital-to-analog converters; the first and second digital data words represent the magnitudes, within the upper voltage range and lower voltage range, respectively, of the analog signals to be driven onto first and second columns of the LCD display. The analog signal generated by the first D/A converter is selected, as by a multiplexer, onto the first column of the display, and the analog signal generated by the second D/A converter is selected onto the second column of the display.

Abstract: Radio frequency power for melting, sealing and welding plastic tubing compressed between a pair of manually or automatically actuated electrically conducting jaws of a hand held or fixed base tubing sealer is regulated by a pulse width modulator controlling the duty cycle of applied constant voltage pulses. A predetermined change of impedance of the tubing during compression and melting is detected to regulate the power applied and to ensure a weld of predetermined physical parameters. On completion of the weld, a first timer is reset and a further weld may be made. In the event of impedance mismatch, a second timer inhibits further application of power and resetting of the first timer. The use of the pulse width modulator enhances conservation of power and accommodates portability of the tubing sealer through use of rechargeable batteries as the power source.

Abstract: A swimming pool debris removal system includes a recirculating pump and a vacuum chamber having an access port, an inlet port, and an outlet port connected to a suction inlet of the pump. The inlet port is connected to receive water and debris pumped from the pool. A removable vacuum seal lid is disposed in the access port, forming a vacuum seal therewith. An air bleed tube coupled to the outlet port draws air trapped between the lid and water in the chamber into the outlet port and suction inlet when the pump is operating, causing the trapped air to be replaced by water and thereby reducing momentum forces of water in the chamber against the lid as the pump is turned off. The lid includes a disk with a circumferential groove and a handle attached to an upper surface of the disk.

Abstract: A method of operating a CMOS microcomputer to minimize power dissipation while accessing a plurality of memories including a first memory operable at a first frequency, a second memory operable at a lower second frequency, including operating the entire CMOS microcomputer at the first frequency while accessing the first memory, causing the CMOS microcomputer to dissipate power at a first level, determining from a user program currently being executed that it is necessary to access the second memory, and operating the entire CMOS microcomputer at the lower second frequency while accessing the second memory to cause the CMOS microcomputer to dissipate power at a second level which is lower than the first level.

Abstract: Residual moisture is removed from an article by placing the article in a chamber, supplying heated fresh air to the chamber via one or more air knives, and evacuating the chamber to remove the residual moisture. The air knives entrain ambient air from within the chamber by Coanda effect air flow, thereby circulating a mixture of fresh air and ambient air about the article. The supply of air to the chamber is interrupted while the chamber is being evacuated to reduce the air pressure within the chamber to on kPa to vaporize residual moisture in the article.

Abstract: A computerized system for teaching handwriting skills to a student displays a character to be written, prompting the student to use a digitizing pen to write the character on a digitizing surface, operating the digitizer to capture pen tilt angle, x,y coordinate values, pen tip pressure, pen tip height, and timing for each pixel. These pen stroke parameters and parameters computed therefrom, including pen tilt direction, are compared with stored corresponding "ideal" or "normal" data and the results of such comparisons are analyzed to determine whether a handwriting "process problem" exists. If so, appropriate "on the spot" corrective feedback information is generated and delivered in audible and/or visual form to the student at the times it will be most beneficial.

Abstract: A multipurpose camera handle includes a base member attachable to the camera. Connected to the base member for rotation about its axis is a first arm which extends transversely of the camera lens axis. A second arm is connected to the first arm at a right angle thereto. The second arm has two telescoping and relatively rotatable sections. A hand grip is connected to the distal end of one of the sections of the second arm. The arrangement permits the hand grip to be positioned at various locations behind, above and beneath the camera.

Abstract: A cellular telecommunications system having a security feature which allows only pre-authorized users no complete cellular telephone calls. The system and method recognizes a cellular radiotelephone's pre-programmed a pre-selected telephone number and a automated number identification code (ANI). The pre-selected telephone number is reserved to the pre-paid cellular telecommunications system. The cellular radiotelephone transmits the ANI and a dialed number identification system code (DNIS) to a cellular switch, which contacts a host computer for call validation the pre-paid service provider.

Abstract: A self-cleaning mixer includes a cylindrical housing and a feedscrew extending longitudinally through the housing for mixing water and cement and conveying the slurry through the housing. A chute at the infeed end of the housing receives a batch of material and directs the material into the housing. The feedscrew turns on a hollow shaft including a plurality of outwardly directed nozzles along a portion of the length of the shaft. The housing includes a plurality of inwardly directed nozzles fed from a pair of manifolds. During a cleaning cycle, one of the manifolds is shut off, thereby increasing the water pressure in the other manifold and increasing the force of the spray to enhance cleaning. The housing is slightly inclined to provide gravity feed of slurry in addition to the feedscrew.

Abstract: A pharmaceutical composition of water, water soluble vinyl polymer gel, amine alcohol dispersant and IEP is used topically to treat herpes labialis and aphthous stomatitis lesions, and also to treat herpes genitalis, chicken pox, allergic conjunctivitis, giant papillary conjunctivitis, stomatitis secondary to chemotherapy, thermal burn, sunburn, decubitus ulcers and shingles.

Abstract: A wrap brush assembly includes an elongated, horizontal upper support arm which pivots from an overhead support about a vertical axis. A pivot link is pivotally connected to the free end of the upper support arm about a horizontal pivot link axis for movement forward and rearward relative to the path traversed by a vehicle to be cleaned. A brush support bracket is pivotally connected to the lower end of the pivot link about an axis lying perpendicular to the pivot link axis for allowing the brush support bracket to swing side to side relative to the path traversed by a vehicle to be cleaned. A motor, brush shaft, and wrap brush are supported from the brush support bracket. A shock absorber dampens forward/rearward movement about the horizontal pivot link axis, and a stop limits inward pivoting movement of the brush support bracket relative to the pivot link to prevent the wrap brush from climbing onto the rear deck of the vehicle.

Abstract: A hood with a depending side wall has vacuum passages formed in the inner surface thereof. An inner shroud positioned internally of the hood cooperates therewith in forming the vacuum passages and has a lower edge elevated above the surface to be cleaned. A foramenous skirt depends from the lower edge of the hood sidewall to contact the surface to be cleaned. The vacuum passages are connected to a source of vacuum. A rotating spray assembly inside the shroud sprays cleaning liquid onto the surface to be cleaned.

Abstract: A quilting frame employs two elongated rails each of which has a pair of legs hingedly attached thereto. Each leg has a foot pivotally mounted at its lower extremity. The pivotal mounting of each foot is such that when the foot is pivoted to a position parallel to the leg and the leg is swung to a position flush with the rail the foot lies alongside the rail.