Patents Represented by Attorney, Agent or Law Firm Thomas F. Lenihan
  • Patent number: 6807496
    Abstract: A real time digital storage oscilloscope acquires a long data record in an acquisition memory and processes the data of the long data record to search for predetermined events. Upon detection of such a predetermined event, circuitry generates an event detect signal, and data comprising an acquisition frame surrounding the event is applied to a waveform processing and display system. The long data record can be replayed in order to perform additional searches throughout the data record using different search criteria, thereby permitting multiple waveforms to be displayed simultaneously, each being captured as a result of a different user-defined event. A screen display may be programmed to display a different kind of event such as Runt signal, Overshoot, or Pulsewidth Violation in each waveform, or to display multiple occurrences of the same kind of event such as Runt signal in each waveform.
    Type: Grant
    Filed: May 2, 2002
    Date of Patent: October 19, 2004
    Assignee: Tektronix, Inc.
    Inventor: John J. Pickerd
  • Patent number: 6804306
    Abstract: A method for generating an in-phase (I) output signal and a quadrature-phase (Q) output signal from an input signal reduces phase error in the I/Q generator by delaying-and-doubling an input signal to produce a Q output signal and delaying the input signal twice and subtracting the same from the input signal to produce an I output signal. The I/Q generator includes a first 90°-phase delay circuit receiving an input signal and outputting an intermediate Q signal; a second 90°-phase delay circuit receiving the intermediate Q signal and producing an intermediate I signal. It also includes a signal doubler receiving the intermediate Q signal and producing a Q output signal of twice the amplitude of the input signal at a 90° phase angle. Finally, the generator includes a signal differencer receiving the input signal and the intermediate I signal and producing an I output signal of substantially twice the amplitude of the input signal at a 0° phase angle.
    Type: Grant
    Filed: January 10, 2001
    Date of Patent: October 12, 2004
    Assignee: Tektronix, Inc.
    Inventors: Daniel G. Knierim, Barton T. Hickman
  • Patent number: 6778931
    Abstract: In a test and measurement instrument having M signal input channels, individual samples representing a signal from each channel are compared to mask pixels to detect non-compliance with a given specification. Initial mask and waveform positions on a display screen of the oscilloscope are determined by an AUTOSET TO MASK function. Comparison of mask pixels and waveform pixels to detect collision between a waveform pixel and a mask pixel (i.e., a mask violation) is performed substantially in real time, as the pixels are being composited into a raster memory by a rasterizer. Acquisitions are performed simultaneously and repeatedly. Acquired waveforms from all M signal input channels are sequentially compared to the mask and drawn on screen during the following acquisition period. Thus, M waveforms can be tested for compliance with a telecom mask substantially within a single acquisition time period.
    Type: Grant
    Filed: July 19, 2000
    Date of Patent: August 17, 2004
    Assignee: Tektronix, Inc.
    Inventors: Peter J. Letts, Steven C. Herring
  • Patent number: 6755561
    Abstract: An elastomeric mat is formed by extruding transparent or translucent elastomeric material. Columns made of the same material guide light from an LED source directly to a light port on top of the column, and diffuse the light substantially throughout the column. A coating of opaque material is used to surround the length of the columns to prevent leakage of light. When mounted adjacent to a front panel, off-axis performance is substantially increased over the prior art by, in effect, bringing the light-emitting source adjacent to a clear port of the front panel. The columns of translucent or transparent elastomeric material function as light pipes, and are formed when making the eleastomeric mat. The columns may be cylindrical or rectangular. Either a rectangular or a cylindrical column of translucent or transparent elastomeric material can convey light to illuminate a legend printed directly on top of the column.
    Type: Grant
    Filed: November 20, 2001
    Date of Patent: June 29, 2004
    Assignee: Tektronix, Inc.
    Inventor: Robert D. Kluser
  • Patent number: 6748335
    Abstract: A real time multi-channel digital storage oscilloscope acquires a relatively long data record for each channel in an acquisition memory and processes the data of the relatively long data record to search for predetermined events. Upon detection of such a predetermined event, circuitry generates an event detect signal, and data comprising an acquisition frame surrounding the event is applied to a waveform processing and display system. The relatively long data record can be replayed in order to perform additional searches throughout the data record using different search criteria, thereby permitting multiple waveforms to be displayed simultaneously, each being captured as a result of a different user-defined event. A screen display may be programmed to display a different kind of event such as Runt signal, Overshoot, or Pulsewidth Violation in each waveform, or to display multiple occurrences of the same kind of event such as Runt signal in each waveform.
    Type: Grant
    Filed: May 6, 2002
    Date of Patent: June 8, 2004
    Assignee: Tektronix, Inc.
    Inventor: John J. Pickerd
  • Patent number: 6728648
    Abstract: Initial mask and waveform positions on a display screen may be determined by an AUTOSET TO MASK function. Upon detection of violations that occur after the AUTOSET TO MASK function is complete, control for further alignment of the waveform under test and the mask is assumed by an AUTOFIT TO MASK function. Comparison of the mask pixels and waveform pixels to detect collision between a waveform pixel and a mask pixel (i.e., a mask violation) is performed substantially in real time, as the pixels are being composited into the raster memory by the rasterizer. In the event of a mask violation, a mask violation signal is generated. In a further embodiment of the invention, in response to the mask violation signal, the AUTOFIT TO MASK function uses display rasterization to automatically redraw the waveform at a new location, until the waveform fits within the mask.
    Type: Grant
    Filed: June 22, 2000
    Date of Patent: April 27, 2004
    Assignee: Tektronix, Inc.
    Inventor: Peter J. Letts
  • Patent number: 6725170
    Abstract: The invention involves storing information about the probe frequency response in the probe itself. The information preferably consists of a set of one or more characteristic frequency response data points. Each data point includes at least the gain of the probe at a given frequency. More preferably, each data point includes the complex transfer characteristic of a probe (S21 in FIG. 2) and optionally the complex output reflectivity of the probe (S22 in FIG. 2) and the frequency (F in FIG. 2) at which the data applies. A variable number of frequency points can be stored, as necessary, to adequately describe the probe's response. The probe also preferably stores a header containing the number of stored data points. The invention readily extends to probes having multiple gain settings or multiple bandwidth settings, by simply storing multiple sets of S21, S22 and F data.
    Type: Grant
    Filed: November 22, 2000
    Date of Patent: April 20, 2004
    Assignee: Tektronix, Inc.
    Inventor: Barton T. Hickman
  • Patent number: 6720828
    Abstract: A high impedance attenuator for use in a test and measurement instrument employs compensation to adjust the low frequency attenuation to match the high frequency attenuation exhibited by the attenuator, rather than attempting to adjust the high frequency attenuation exhibited by the attenuator. In an alternate embodiment of the invention, compensation to adjust low frequency attenuation is employed in a feedback loop and an opposite compensation is applied in a parallel attenuation stage to stabilize the input resistance. In yet another embodiment of the invention, compensation to adjust low frequency attenuation is employed by means of an R-C time constant of an additional R-C circuit in a feed forward loop. This additional time constant is matched to the R-C time constant of the input R-C network. The input resistance of the attenuator is not changed.
    Type: Grant
    Filed: November 21, 2001
    Date of Patent: April 13, 2004
    Assignee: Tektronix, Inc.
    Inventors: Theodore G. Nelson, Michael P. Khaw, Daniel G. Knierim, John F. Stoops
  • Patent number: 6704830
    Abstract: An expanded WIRE-OR Bus structure has a first WIRE-OR Bus arrangement and a second WIRE-OR Bus arrangement. Each of the first and second WIRE-OR Bus arrangements have connected thereto at least one driver element and at least one receiver element. An intelligent bi-directional signal coupling circuit includes a buffer element, a bus arbiter, and a bus driver amplifier. The coupling circuit couples signals between the first WIRE-OR bus and the WIRE-OR second bus, and prevents signals originating on one of the WIRE-OR buses from being coupled back to the same WIRE-OR bus.
    Type: Grant
    Filed: December 19, 2000
    Date of Patent: March 9, 2004
    Assignee: Tektronix, Inc.
    Inventors: Kevin C. Spisak, Michael S. Hagen
  • Patent number: 6693576
    Abstract: A method and apparatus enabling the substantially concurrent operation of multiple decimators within a digitizing measurement device such as a digital storage oscilloscope (DSO), wherein the multiple decimators provide multiple processed sample streams that may be used for a composite presentation of input signal data.
    Type: Grant
    Filed: May 23, 2002
    Date of Patent: February 17, 2004
    Assignee: Tektronix, Inc.
    Inventor: Frederick A. Azinger
  • Patent number: 6674026
    Abstract: A rear-mount integrated rotary encoder comprises a mechanical portion and a printed circuit board portion. The mechanical portion of a rear mount integrated rotary encoder comprises a housing including a bushing for receiving one end of a rotatable shaft. The rotatable shaft passes through an open front portion of the housing and is mechanically connected to exposed rotatable circuit contacting members. The printed circuit board portion has an encoder contact pattern formed thereon. The printed circuit board has an area larger than the cross sectional area of the housing. The encoder contact pattern surrounds (or is at least concentric with respect to) an aperture in the circuit board. The rotatable shaft of the rotary encoder is passed through the aperture such that the rotatable circuit contacting members contact the encoder contact pattern on the circuit board.
    Type: Grant
    Filed: May 10, 2002
    Date of Patent: January 6, 2004
    Assignee: Tektronix, Inc.
    Inventors: James H. McGrath, Jr., David F. Hiltner
  • Patent number: 6642926
    Abstract: A telecom mask testing zoom function draws mask. pixels into a raster memory. In this way, the mask is treated as a waveform. Comparison of the mask pixels and waveform pixels to detect collision between a waveform pixel and a mask pixel (i.e., a mask violation) is performed substantially in real time, as the pixels are being composited into the raster memory by the rasterizer. The mask is scalable and repositionable by the rasterizer under control of a controller, because it is treated as a waveform. The mask is lockable to the waveform because both are stored in pixel form in raster memory by the rasterizer under control of the controller.
    Type: Grant
    Filed: June 29, 2000
    Date of Patent: November 4, 2003
    Assignee: Tektronix, Inc.
    Inventor: Peter J. Letts
  • Patent number: 6642741
    Abstract: An integrated circuit includes a termination for a transmission line having a predetermined characteristic impedance. The termination includes a controllable impedance circuit, including a multiplier, coupled to the transmission line. A reference impedance, placed external to the integrated circuit, has an impedance related to the characteristic impedance of the transmission line.
    Type: Grant
    Filed: December 12, 2001
    Date of Patent: November 4, 2003
    Assignee: Tektronix, Inc.
    Inventors: Arthur J. Metz, Daniel G. Knierim, Richard J. Huard
  • Patent number: 6640273
    Abstract: Apparatus for data bus expansion between two instrument chassis comprises a first interface circuit, a connecting cable, and a second interface circuit. Detection circuitry in each interface circuit detects slot position. Slot position determines direction of address and data flow for each card. One of the first and second interface circuits is connected to a controller slot in a first chassis, and the other of the first and second interface circuits is connected to a non-controller slot in a second chassis. Bus interface circuitry for signal and identification are reconfigured in accordance with slot determination. As a result, the assembly formed by connection of two substantially identical interface cards with a cable, is symmetric and reversible.
    Type: Grant
    Filed: December 19, 2000
    Date of Patent: October 28, 2003
    Assignee: Tektronix, Inc.
    Inventors: Kevin C. Spisak, Michael S. Hagen
  • Patent number: 6624721
    Abstract: Apparatus for monitoring a signal at an intermediate point on a series impedance source terminated unidirectional transmission line employs a voltage probe, a current probe, and a summing element. The apparatus provides a useful output signal despite the fact that signals at an intermediate point on the transmission line comprise the sum of incident and reflected waveforms. The voltage probe derives a signal from the transmission line that is representative of the sum of the incident and reflected waveforms. The current probe produces a voltage signal representative of the difference between the incident and reflected waveform currents. The summing circuit algebraically adds the output signals of the voltage and current probes, and produces an output signal representative of only one of the transmitted waveform or the reflected waveform.
    Type: Grant
    Filed: October 13, 2000
    Date of Patent: September 23, 2003
    Assignee: Tektronix, Inc.
    Inventors: Michael S. Hagen, Einar O. Traa
  • Patent number: 6614434
    Abstract: A method for controlling a digital oscilloscope locates a crossing level in an eye diagram (also including a crossing time), of a communications signal. The method includes the steps of locating the crossing time using a horizontal histogram box; and locating the crossing level using a vertical histogram box placed at a horizontal location substantially at the located crossing time.
    Type: Grant
    Filed: June 14, 2000
    Date of Patent: September 2, 2003
    Assignee: Tektronix, Inc.
    Inventor: Warren A. Finke
  • Patent number: 6615148
    Abstract: A “Streaming Distributed Oscilloscope” (SDO) architecture comprises at least one channel including a preamplifier module, a Digitizer Module, and an Acquisition Memory Module. An SDO couples all acquired samples of a waveform being monitored to all of its processing boards. Because multiple processor boards can access all of the sample data, an SDO can perform measurements on substantially all samples of a continuous data stream without dead time. An SDO is readily expandable in terms of memory length by simply adding more memory boards, and can be reconfigured by a user by virtue of its object-oriented architecture. An SDO waveform is defined by a trigger source and an acquisition memory. An SDO is capable of acquiring multiple waveforms based upon different triggers from the same data stream in the same channel. An SDO timebase for a given channel is defined by a decimator followed by an acquisition memory. Multiple timebases can co-exist in the same SDO channel.
    Type: Grant
    Filed: April 5, 2001
    Date of Patent: September 2, 2003
    Assignee: Tektronix, Inc.
    Inventor: John J. Pickerd
  • Patent number: 6571185
    Abstract: Multiple views of the signal are generated by a time-sharing use of the oscilloscope's acquisition hardware. The instrument software makes a set of measurements of the input signal, and from the results of those measurements classifies the input signal as to type. Signals of particular types implicitly select suites of views of the signal. The operator sees examples of the other views available while a related view is the main view. Alternate views can be “live” miniature views, and displayed alongside in simplified form, alongside the main view. By clicking on them, these alternative views may be made to become the main view. The operator can add and modify views. Each view comes with a set of measurements that are automatically performed and the results are displayed on the screen as text annotation to the waveform. A different view of the signal comes with different automatic measurements, and presents the results of these measurements as annotations to the waveform image.
    Type: Grant
    Filed: April 20, 1999
    Date of Patent: May 27, 2003
    Assignee: Tektronix, Inc.
    Inventors: Michael A. Gauland, Steven K. Sullivan, Roy I. Siegel, Frederick A. Azinger, Charles L. Saxe
  • Patent number: 6563365
    Abstract: A method for reducing noise in a four-quadrant multiplier having first and second cross-coupled pairs of differential bipolar transistors, differential input current terminals connected with a first pair of common junctions of the respective pairs of differential transistors and the differential output current terminals cross coupled to form a second pair of common junctions of the respective pairs of differential transistors is described. The method includes providing a noise current path from the differential input current terminals to a bias voltage, the noise current path substantially bypassing the differential output current terminals when the gain of the multiplier is near zero.
    Type: Grant
    Filed: January 10, 2001
    Date of Patent: May 13, 2003
    Assignee: Tektronix, Inc.
    Inventors: Daniel G. Knierim, Barton T. Hickman
  • Patent number: 6543098
    Abstract: A facility for mounting an electronic component includes a first circuit board having of mounting apertures. A mounting element is associate with each aperture, and includes a boss defining a bore. The boss has a first surface contacting a major surface of the first circuit board, and a second surface opposite the first surface. A pin is received in the bore, and has a lower portion protruding from the first surface of the boss and into one of the apertures. The pins lower portion definves a spece to capture a portion of the first circuit board. A fastener connected to the pin may generate compression between the spece and the boss to secure the board, and a corner-shaped protrusion on the second surface may constrain the corner periphery of a second board resting on the second surface, with the fastener also securing the second board against the boss.
    Type: Grant
    Filed: March 2, 2001
    Date of Patent: April 8, 2003
    Assignee: Tektronix, Inc.
    Inventors: Daniel B. Meyer, Kevin Taylor, Mike A. Vilhauer, J. Steve Lyford