Abstract: A video signal clamp involves evaluating the difference between the signal level and the desired clamp level during the back porch interval. A correction signal indicates whether the signal level must be increased or decreased to establish the desired clamp level. Generation of the correction signal involves a median filter algorithm. Any required increase or decrease of the signal level occurs continuously throughout each horizontal line interval.

Abstract: A differential current source (50) provides first and second complementary output currents (I1, I2) responsive to a video input signal (S1) which are coupled via respective load networks (52,54) to a common supply terminal (22) and develop first and second complementary video output signals (V1,V2). A first output circuit (56) applies the first output signal to a first output terminal (16) via a voltage follower transistor (Q6) and applies the second output signal to the first output terminal via a current source transistor (Q8). A second output terminal (18) is similarly driven by a second voltage follower transistor (Q5) and a second current source transistor (Q7), all transistors being of the same conductivity type. A tri-state control circuit (Q1,Q2) coupled to the differential current source enables the differential current source in a first operating mode to produce the first and second complementary currents whereby push pull output signals are produced at the output terminals.

Abstract: A method and apparatus for routing a telephone call through a telephone network from a caller to a called party designated by the caller via advertising service apparatus that operates in two modes successively, the parties being in communication with each other in one mode and ads are selected from storage during that mode and the ads are impressed on one or both of the parties during a different mode. Selection of ad messages for use is controlled by many criteria. Delivery of ad is recorded for accounting purposes. The modes may alternate between message intervals whose duration is determined by ad message length and communication intervals whose length is determined by a talking time timer.

Abstract: A VCR controls a cable box, and monitors television signals received from the cable box in a "closed loop" manner. By monitoring an appropriate signal the controller of the VCR can detect perturbations of signal level which indicate that the cable box has changed channels. That is, the output signal of the cable box remodulated on, for example, the RF carrier frequency of channel 3, will be momentarily lost during the period in which the cable box changes channels. Thus, the subject apparatus can determine if the cable box is "off" or "on" by issuing a channel change command and observing if the cable box responds to the channel change command. In one embodiment of the invention the VCR causes an on-screen display of an error message if it determines that it is unable to control the came box.

Abstract: A device for preventing contamination of a clean room during the performance of unclean work. Wall members are provided to be connected in series, to surround and isolate the unclean work. Each wall member includes an interlocking receiving channel that can be slipped over the frame member of an adjacent wall member. This allows the wall members to be connected in series. Each wall member also has wedging means that allows the wall member to be tightly wedged between the ceiling and floor of the clean room, to prevent contaminants produced by unclean work from traveling from the work area to the rest of the clean room. If the unclean work includes making an opening in the wall of the clean room, a similar arrangement can be constructed on the opposite side of the wall, if that area also needs to be kept clean.

Abstract: A tower light controller comprises logic circuitry that easily connects with equipment used in the production of semiconductor wafers. The tower light controller uses the existing signals in the production equipment, namely a process signal, an alarm signal, left and right cassette present signals, and left and right atmosphere signals, to appropriately drive a light tower comprised of a yellow lamp, a red lamp, and a green lamp. The logic circuitry turns on the green lamp when a product is being run. A yellow lamp is continuously driven when the equipment has wafers that are ready to be unloaded and the yellow lamp is flashed when the equipment is ready to be loaded with wafers. The red lamp is flashed during alarm conditions and is driven continuously when the equipment is placed in a repair or in a preventative maintenance mode. The logic circuitry also comprises an oscillator formed by a series connection of three inverters.

Abstract: A data transmission system includes a source of a data signal and a modulator, responsive to the data signal, producing a first modulated signal representing the data signal and a second modulated signal representing a signal 180 out-of-phase with the data signal. The first and second modulated signals are transported via a transmission channel. A first demodulator demodulates the transported first modulated signal and a second demodulator demodulates the transported second modulated signal. A subtractor, responsive to the first and second demodulators, produces a signal representative of the data signal.

Abstract: A probe board is provided with a guide-mask system. The probe board has at least one head which passes through a respective guide-hole located on the filmed guide-mask. The utilization of this guide-mask has the advantage of minimizing slipping of probe heads out of respective mating test terminals of IC chips. Additionally, the utilization of this guide-mask provides accurate probe head positioning and provides enforcement to the heads by way of the filmed guide-mask because of the precise support holes provided in the masks.

Abstract: An impedance matching, reducing, or buffering circuit for permitting smooth signal flow from a first transmission medium to a second transmission medium. The circuit provides a first node adapted for coupling to the first transmission medium and for receiving a signal from the first transmission medium. The circuit further provides a buried channel transistor, that is coupled to the first node and that is biased by additional circuit devices, for transforming the impedance imposed on the signal. The use of the buried mode transistor reduces noise on the surface of the transistor while at the same time keeps other performance standards high. The circuit additionally provides a second node that is coupled to the buried channel transistor and that is adapted for coupling to the second transmission medium for conveying the signal to the second transmission medium.

Abstract: An audio follow video mixer is disclosed which has a display that provides a plurality of monitor indicator LEDs corresponding to a selected audio channel. These LEDs visually indicate which channels are currently being monitored, including playback channels and line out channels. This invention permits an operator to determine which channel is being monitored during a preview operation.

Abstract: The method of making the casing comprises the steps of preparing a powder mixture consisting predominantly of a metal powder mixed with a minor proportion of graphite powder ranging from about 0.2% to about 2%, preferably 0.8% by weight, while the metal powder ranges from about 99.8% to about 98% by weight. The powder material is compressed into a casing mold to a molded density ranging from about 0.21 to about 0.24, preferably 0.23 of a pound per cubic inch. The molded powder is sintered in an inert atmosphere at a temperature ranging from about 1500 to about 1700, preferably 1600.degree. F. for a time sufficient to unite the molded powder into a brittle porous frangible casing. The graphite powder vaporizes and escapes from the molded casing during the sintering step whereby porosity and frangibility are imparted to the casing.

Abstract: A relay circuit connects the headlight circuit and wiper circuit of a motor vehicle to actuate the low-beam lamps whenever the windshield wipers are activated. The relay circuit includes a delay circuit to permit continuous operation of the headlights even during intermittent operation of the windshield wipers, and an interlock to prevent operation to prevent the low beams and high beams from being simultaneously operated. Further, the relay circuit includes means to prevent operation of the vehicles instrument lights as a warning to the operator.

Abstract: A video display having raster correction comprises a cathode ray tube with a deflection coil mounted thereon for raster generation. A deflection amplifier is coupled to the deflection coil for generating a deflection current therein. A corrective waveform modulator is coupled to the deflection amplifier for generating a first corrective current in the deflection coil. An auxiliary coil is mounted on the cathode ray tube for raster correction. An auxiliary coil drive amplifier is coupled to the auxiliary coil for generating a second corrective current in the auxiliary coil. A first corrective signal is coupled to the waveform modulator for generating raster correction at a first raster edge and a second corrective signal is coupled to said auxiliary coil drive amplifier for generating raster correction at an edge opposite the first raster edge.

Abstract: An instrument for surface analysis includes rastering an electron beam across an anode to generate x-rays. A concave Bragg monochromator focuses an energy peak of the x-rays to a specimen surface, the x-rays rastering the surface to emit photoelectrons. An analyzer provides information on the photoelectrons and thereby chemical species in the surface. A second detector of low energy photoelectrons is cooperative with the rastering to produce a scanning photoelectron image of the surface for imaging of the specimen. Alternatively a lens formed of two concave grids transits the photoelectrons to the analyzer with selectively modified energy so that the analyzer detects either higher energy electrons characteristic of chemical species or lower electrons for the image. The monochromator is formed of platelets cut from an array of platelets in a single crystal member.

Abstract: A video display has a first format display ratio. A mapping circuit maps an adjustable picture display are on the video display. A signal processor generates first and second video signals from input video signals having one of different format display ratios. A switching circuit selectively couples video signal sources as the input video signals. The signal processor can manipulate data from the input video signals by selective interpolation and cropping. A synchronizing circuit synchronizes the first and second signal processors with the mapping circuit. A selecting circuit selects as an output video signal between one of the first and second processed video signals and a combination of the first and second processed video signals. A control circuit controls the mapping circuit, the first and second signal processors and the selecting circuit to adjust in format display ratio and image aspect ratio each picture represented in the output video signal.

Abstract: Cache memory input/output apparatus that allows transfer of a single data word and transfer of consecutive sequences of data words in a row of memory, using two independent serial ports and a random access port whose actions are controlled in part by a memory address signal. Data transferred by the serial ports are double buffered, each serial port having two independent registers; and the two registers associated with a serial port may be ganged together to transfer data sequences having word lengths from 16, or multiples thereof, up to arbitrary multiples of the length of a row of data words.

Abstract: Each of the signal processing units of a digital signal processing system is provided with a programmable timing delay unit having identical programming interface to control the signal timing of its signal processing circuitry. Additionally, a central timing unit is provided to the digital signal processing system to provide signal timing control inputs to the programmable timing delay units. Furthermore, a routing switcher is provided to the digital signal processing system to control configuration of the signal path, i.e. the order in which the signal is processed by all or a subset of the signal processing units of the digital signal processing system. As a result, the individual signal processing units are relieved the burden of providing circuitry for timing control, delay equalization and timing derivation.

Abstract: A disposable electrical connector header includes a base portion having a plurality of pin-receiving passages being open on one side. An external adjacent spring member to the open side of the passages provides an interference fit when a terminal pin is inserted from the bottom of the base portion of the disposable header. A plurality of terminal pins are received in the passages and project from the disposable header for insertion into holes in a printed circuit board and for solder connection to circuit traces on the circuit board. The disposable header is then slid off the terminal pins after soldering to the printed circuit board. A top portion is also provided having pin stops located correspondingly above each of the passages to restrict the movement of the terminal pins once inserted into the passages of the disposable header. A flat top at the upper portion of the disposable header is provided for robotic placement or removal of the disposable header.

Abstract: A capacitive liquid level sensor having phase detecting circuitry incorporates a capacitive sensor array, an oscillator generating an input signal, a switching circuit sequentially coupling the input signal to the input plates of the capacitive sensor, one at a time, a pair of phase lock loop circuits (PLLs) each having voltage controlled oscillators (VCOs), a second switching circuit selectively coupling the output plates of the capacitive sensor array, in sequential fashion, to the PLLs, and an exclusive OR-gate (XOR) receiving the outputs of the VCOs from each of the PLLs. The XOR generates a first logic level signal when a difference in the phase of two signals from any two adjacent output plates indicates that a phase difference is present. A second logic signal is generated if no phase difference is detected. The signals are perfectly in phase when any two adjacent output plates are either submerged in fluid or both disposed in air.