Patents Assigned to Tektronix, Inc.
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Patent number: 5481230Abstract: A phase modulator circuit and method for generating an output signal having individually positionable edges is described. The phase modulator includes a programmable pulse generator, such as an interval counter, or a delay for producing the output signal, and a control value source, such as a memory, for delivering a sequence of control values to the generator. The control values determine the time between successive output pulses.Type: GrantFiled: November 14, 1994Date of Patent: January 2, 1996Assignee: Tektronix, Inc.Inventors: Paul Chang, Dan H. Wolaver, J. Howell Mitchell, Jr.
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Patent number: 5479186Abstract: A video monitor color control system including means for calibrating the intensity response of CRT phosphor sets to each of a plurality of electron gun control levels. Provided is a processor (24) that generates a sequence of discrete DAC signals, each DAC signal identifying an electron gun and a DAC value for driving the electron gun at a selected control level. Also provided is a monitor driver (22) connected to the processor (24) and to the monitor (20) and controllable in response to a DAC signal for driving the electron gun identified by the DAC signal at the control level identified by the DAC signal. The driven electron gun excites the associated phosphor set. A sensor (28) is provided for detecting the luminous intensity level of the phosphor excited by the electron gun, and for converting the detected intensity into a representative signal.Type: GrantFiled: February 11, 1991Date of Patent: December 26, 1995Assignee: Tektronix, Inc.Inventors: Paul A. McManus, Robert J. Beaton
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Patent number: 5477135Abstract: A current probe comprising a Hall device and a secondary winding in a flux linking relationship with a magnetic circuit is self-calibrated by disconnecting the Hall device from the winding, passing a current through the winding so as to induce a magnetic flux in the magnetic circuit, measuring voltage developed by the Hall device in response to linking by the magnetic flux, calculating the Hall gain of the Hall device, and then adjusting the gain of a scaling output amplifier on the basis of the calculated Hall gain to compensate for variation in Hall gain due to changes in operating conditions.Type: GrantFiled: February 28, 1995Date of Patent: December 19, 1995Assignee: Tektronix, Inc.Inventor: Clifford E. Baker
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Patent number: 5473361Abstract: A test and measurement system for a cable television (CATV) system measures parameters of a broadband video signal at the headend of the CATV system. Characteristic data is generated from the measured parameters and combined with the broadband video signal for transmission over the distribution system of the CATV system. Also out of service video channels are detected at the headend, and a test sequence is combined with the broadband video signal for each out of service channel. In the field a receiver is coupled to a point in the distribution system to measure the parameters of the broadband video signal at that point. The parameters measured at the receiver are compared with the parameters measured at the headend, as derived from the transmitted characteristic data. The differences between the two sets of parameters are displayed to present a display of the characteristics of the CATV system, with out of service channels represented by the test sequences.Type: GrantFiled: March 21, 1994Date of Patent: December 5, 1995Assignee: Tektronix, Inc.Inventor: Bruce J. Penney
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Patent number: 5471159Abstract: One embodiment of a circuit and corresponding method for generating a trigger signal upon the occurrence of either set up or hold time violations in the same waveform acquisition produces a trigger signal referenced to, but displaced in time from, the input clock signal. Transitions (13) in a data signal initiate a window pulse (14') whose duration is equal to the sum of a set up time requirement and a hold time requirement. The window pulse is used as the D input to a flip-flop (20) that is clocked by a version of a clock signal whose active edge has been delayed (28) for an interval that corresponds to the hold time requirement. The output of the flip-flop (20) is a trigger signal that only occurs when a set up or hold time violation has occurred. In another embodiment, triggers generated as the result of a set up time violation are referenced to the clock edge, while triggers that are generated as the result of a hold time violation are referenced to a transition in the data signal.Type: GrantFiled: September 18, 1992Date of Patent: November 28, 1995Assignee: Tektronix, Inc.Inventors: Carlton Stuebing, George J. Caspell
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Patent number: 5471228Abstract: Crosstalk is reduced in any type of active matrix electro-optical display system (10) by applying a compensating signal, the value of which is dependent upon multiple data drive signals. In a preferred embodiment, a single compensating signal, equal to the inverse weighted average of all of the data drive signals applied during a row address period, can be applied to all data electrodes (20) after the data drive signals are stored in display elements (16). Such a compensating signal simultaneously reduces side-to-side crosstalk and front-to-back crosstalk to levels previously achievable for only one type of crosstalk at a time.Type: GrantFiled: February 1, 1994Date of Patent: November 28, 1995Assignee: Tektronix, Inc.Inventors: Kevin J. Ilcisin, Dennis W. Prince
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Patent number: 5469188Abstract: A method of pre-analyzing video signals obtained from a digital image stores the digital image in a frame buffer store in a specified video digital format. The amplitude, saturation and frequency of the stored digital image when converted into another video format, such as RGB or composite broadcast video, are each analyzed independently to identify areas of the stored digital image that might produce distortions in the final video format when displayed. Amplitude analysis is accomplished by converting the stored digital image into an RGB image, and each component is compared with predetermined limits to detect amplitude errors. Saturation analysis is accomplished by generating a saturation signal from the chrominance components of the stored digital image, and then comparing a function of the saturation signal with predetermined limits to detect oversaturation errors.Type: GrantFiled: April 27, 1992Date of Patent: November 21, 1995Assignee: Tektronix, Inc.Inventors: Suresh Krishnamurthy, Robert A. McCormick, Kenneth F. Cone, Gary L. Brown, Ronald W. Bryant
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Patent number: 5465222Abstract: A barrel shifter or multiply/divide integrated circuit (IC) structure includes a plurality of stages in series. The number of stages is a function of the number of bits in an input digital data word, and each stage in sequence provides for a different power of two rotary or multiply/divide shift of the digital data word at the input if selected. A multiplexer in each stage selects as an output either the shifted digital data word or the input digital data word for output to the next stage according to a shift amount select command. At the input and output of the series of stages an additional reversal multiplexer selects in response to a shift direction command either the digital data word or a reversed version of the digital data word, which determines the effective direction of the shift in the stages. Logic may be included in each stage to determine whether the shift operation is a rotary or multiply/divide shift operation.Type: GrantFiled: February 14, 1994Date of Patent: November 7, 1995Assignee: Tektronix, Inc.Inventor: Michael C. Seckora
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Patent number: 5462591Abstract: An aqueous phase change ink contains a selected concentration of hyperthermogelling component that causes the ink to gel when its temperature is increased to its thermo-inversion point or when the concentration of the hyperthermogelling component is increased by evaporation, or substrate absorption, of water from the ink. The ink may be jetted directly onto a heated and/or absorptive substrate or jetted onto a cooler and/or hydrophobic surface before being transferred to the substrate. The thermo-inversion point is preferably about ambient temperature, and the preferred hyperthermogelling component is a nonionic surfactant, such as an ethylene oxide propylene oxide block copolymer surfactant.Type: GrantFiled: May 6, 1994Date of Patent: October 31, 1995Assignee: Tektronix, Inc.Inventors: B. M. Karandikar, Loc V. Bui, Hue P. Le
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Patent number: 5461395Abstract: A plasma addressing structure having data storage elements (16) uses an ionizable gas to store data in and read data out of the storage elements. The storage elements are defined by the overlapping areas of multiple column electrodes (18) extending in a common direction on a first substrate (22) and multiple channels (20) extending in a common direction on a second substrate (24). A layer of pliant dielectric material (26) separates the first and the second substrates, which are positioned face to face and spaced apart with the direction of the channels transverse to that of the column electrodes. Each of the channels is filled with an ionizable gas and includes two electrodes (46 and 48) electrically isolated from each other. The ionizable gas functions as an electrical switch. The storage element includes a layer (32) of liquid crystal material and receives incident image-carrying light.Type: GrantFiled: March 8, 1993Date of Patent: October 24, 1995Assignee: Tektronix, Inc.Inventor: William W. Stein
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Patent number: 5459466Abstract: A first subset of components of a first set of pairs of complementary differential electrical signals representative of a numerical value expressed in a multi-bit thermometer code, is processed in accordance with a first set of Boolean functions to produce a first set of output electrical signal components , and a second subset of components of the first set of pairs of complementary differential electrical signals is processed in accordance with a second set of Boolean functions to produce a second set of output electrical signal components. The first and second subsets and the first and second sets of Boolean functions are such that the first and second sets of output electrical signal components when combined form a second set of pairs of complementary differential electrical signals representative of the same numerical value expressed in a second multi-bit code with fewer bits than the multi-bit thermometer code.Type: GrantFiled: February 23, 1995Date of Patent: October 17, 1995Assignee: Tektronix, Inc.Inventors: Daniel G. Knierim, Scott L. Williams, Keith H. Lofstrom
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Patent number: 5455620Abstract: A system for automatic generation of vector reference graticules for a vectorscope display acquires the active video portion of a video signal that includes a color bar test signal. The values for each color difference component at each reference color plateau for the acquired color bar test signal are averaged to provide horizontal and vertical displacement values for each reference color, including black. Graticule boxes are electronically generated and positioned for each reference color on a display according to the respective horizontal and vertical displacement values.Type: GrantFiled: January 21, 1994Date of Patent: October 3, 1995Assignee: Tektronix, Inc.Inventors: Douglas C. Stevens, James L. Tallman
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Patent number: 5455604Abstract: A printer accurately controls the passage of print media therethrough and maintains the print media taut as the print media passes through a printing zone while the media is printed by an ink jet printer. The print media sheet is preferably carried by a rotating drum in a first direction through the printing zone, with the drum being reversed to cause the exiting of the print media sheet from the printer. A pressure fixing or fusing apparatus may be positioned to flatten ink spots on the print media as the print media exits from the printer. The pressure fixing or fusing mechanism is preferably used in the case of a hot-melt or phase-change ink jet printer.Type: GrantFiled: August 15, 1994Date of Patent: October 3, 1995Assignee: Tektronix, Inc.Inventors: Ronald L. Adams, Charles Bradford, Edward F. Burke, Eldon P. Hoffman, Rodney B. Gilbert, James D. Rise, Arthur C. Van Horne
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Patent number: 5455615Abstract: An improved ink jet print head includes tapered manifolds (222), ports (234), and inlet channels (214) all leading elevationally upward to sweep bubbles from the head, aided by their buoyancy. The ports opening to the inlet channels are distributed at staggered locations throughout the manifolds with at least some of the ports located adjacent to the elevationally highest edge of each manifold. This aspect of the invention reduces bubble entrapment and improves jetting performance by reducing acoustic cross-talk among ink pressure chambers (204) of the head. Moreover, tapering the ink supply manifolds and other features causes more uniform ink flow rates and reduces flow rate stagnation regions within the head. Purging cycles therefore require smaller volumes of ink than with prior designs.Type: GrantFiled: April 30, 1993Date of Patent: October 3, 1995Assignee: Tektronix, Inc.Inventors: Ronald F. Burr, Laurent A. Regimbal, John S. Moore
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Patent number: 5453660Abstract: An electrode structure (100) for an addressing structure using an ionizable gaseous medium has a substrate (102) and a cover (126). A plurality of channel-defining portions (116, 118, 120, 122, 124) each extend from the substrate to the cover; each pair of adjacent channel-defining portions defines a plasma discharge channel (129, 131, 133, 135, 137) for the ionizable gaseous medium. An electrode (104, 106, 108, 110, 112) extends through each channel-defining portion so that the electrode has a surface exposed to each of the channels defined in part by the channel-defining portion. Each of the channel defining portions or walls separates each electrode from the cover. An addressing structure using the electrode structure of the invention ionizes the gas in each channel by driving the electrodes of the pair of adjacent channel-defining portions that define the channel.Type: GrantFiled: September 15, 1994Date of Patent: September 26, 1995Assignee: Tektronix, Inc.Inventors: Paul C. Martin, Thomas S. Buzak
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Patent number: 5452010Abstract: A system for synchronizing asynchronous video signals with a reference signal for input to a digital video processing system has a first-in, first-out (FIFO) buffer for each input signal that writes the digitized video signal into the FIFO under control of an input clock signal derived from the digitized video signal, and reads the digitized video signal from the FIFO under control of the reference signal. An input state machine monitors the digitized video signal at the input and the occupancy of the FIFO to provide a write enable signal to the FIFO so long as the FIFO is not in danger of overflowing. An output state machine monitors the digitized video signal at the output and the occupancy of the FIFO to provide a read enable signal to the FIFO so long as the FIFO is not in danger of underflowing.Type: GrantFiled: July 18, 1994Date of Patent: September 19, 1995Assignee: Tektronix, Inc.Inventor: Douglas J. Doornink
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Patent number: 5448589Abstract: An automatic equalizer has a circuit for sensing cable effects that generates a control signal for a variable equalizer. A digital signal from a transmission channel is input to the variable equalizer to produce an equalized digital signal as a function of the control signal. The equalized digital signal is input to the sensing circuit which detects over-shoot or under-shoot of transitions in the equalized digital signal and adjusts the control signal accordingly to produce a balance in the transitions.Type: GrantFiled: August 1, 1994Date of Patent: September 5, 1995Assignee: Tektronix, Inc.Inventor: Barry A. McKibben
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Patent number: 5446650Abstract: Methods for producing logic signal displays for an instrument known as a "logic oscilloscope" are disclosed. A digital input signal is first sampled as an analog signal to produce multi-bit digital samples that are representative of the amplitude of the input signal over time. The multi-bit digital samples are then processed using interpolative techniques to ascertain when the input signal crossed a hypothetical logic level threshold or pair of thresholds and when the signal was in one logic state or the other. The resulting transition times and logic states are then used as the basis for generating a variety of digital displays, including logic timing diagrams, state table displays, and cursor readouts similar to those available in a logic analyzer. Setup and hold time violations and measurements may also be obtained using this information.Type: GrantFiled: October 12, 1993Date of Patent: August 29, 1995Assignee: Tektronix, Inc.Inventors: Craig Overhage, Richard Austin
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Patent number: D365527Type: GrantFiled: February 17, 1995Date of Patent: December 26, 1995Assignee: Tektronix, Inc.Inventors: Scott Peterson, Scott R. Ketterer, John B. Gilbert
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Patent number: D365997Type: GrantFiled: March 3, 1995Date of Patent: January 9, 1996Assignee: Tektronix, Inc.Inventors: Jerry L. Wrisley, Keith W. Kirkwood, David T. Rosette