Patents Represented by Attorney, Agent or Law Firm Thomas F. Lenihan
  • Patent number: 7219174
    Abstract: A method and apparatus in which a plurality of demux processors propagates respective received sample streams to adjacent demux processors via an inter-demux bus; and wherein a final one of the plurality of demux processors propagates all of the respective received sample streams toward a next processing element such as a multi-drop bus (MDB) or system processor within a data acquisition device.
    Type: Grant
    Filed: February 12, 2003
    Date of Patent: May 15, 2007
    Assignee: Tektronix, Inc.
    Inventors: Paul M. Gerlach, Samuel J. Peters
  • Patent number: 7191079
    Abstract: An advanced trigger circuit includes two trigger decoders, each triggering on one of respective pluralities of continuous-time trigger events. In one embodiment, a programmable timer begins timing in response to an output signal of the first trigger decoder and generates an end-of-time signal at the expiration of its time period. A reset circuit resets the first trigger decoder if the second selected continuous-time trigger event failed to occur before the end-of-time signal was generated. In another embodiment, a reset decoder generates a reset signal in response to an occurrence of a selected continuous-time trigger event. The reset circuit is responsive to the reset signal for resetting the first trigger decoder if the second selected continuous-time trigger event failed to occur before the reset signal was generated. In other embodiments, the advanced trigger circuit triggers on a serial lane skew violation or on a beacon width violation.
    Type: Grant
    Filed: March 23, 2005
    Date of Patent: March 13, 2007
    Assignee: Tektronix, Inc.
    Inventors: Patrick A. Smith, Que Thuy Tran, John C. Delacy, Daniel G. Knierim, David L. Kelly, John C. Calvin
  • Patent number: 7114956
    Abstract: An insulated Bayonet Neill Concelman (BNC) connector includes a replaceable non-metallic insulating shell. The non-metallic shell is attached to a metallic portion of the BNC connector such that, when mounted on an oscilloscope, or other electronic instrument, the non-metallic shell may be disconnected from the metallic portion of the BNC connector without having to gain access to the interior of the instrument housing. Thus, in the event of damage to the non-metallic shell, the damaged non-metallic shell may be quickly and easily replaced by a user, instead of having to return the instrument to the manufacturer for repair.
    Type: Grant
    Filed: December 16, 2004
    Date of Patent: October 3, 2006
    Assignee: Tektronix, Inc.
    Inventors: Robert R. Kreitzer, James H. Mc Grath, Jr.
  • Patent number: 7110897
    Abstract: The subject apparatus and method measures the Total Average Power Loss and isolates the different power loss components of Total Average Loss such as Ton Loss and Toff loss at switching devices such as, MOSFETs, BJTs and IGBTs that may be used in a switching power supply. It provides separation of the components of Total Average Loss as Turn Ton Loss, Turn Toff Loss and allows derivation of conduction loss. It also has the capability to measure Total Average Loss and Switching Loss, while amplitude, duty cycle and frequency of the switching signal is varying in a switching power supply.
    Type: Grant
    Filed: September 20, 2004
    Date of Patent: September 19, 2006
    Assignee: Tektronix, Inc.
    Inventors: Srikrishna H. Nadig, Godfree Coelho
  • Patent number: 7071787
    Abstract: A phase locked loop type frequency synthesizer utilizing a reference signal source includes a voltage controlled oscillator (VCO), a phase comparator, a programmable pre-scaler and a modulator. The programmable pre-scaler divides the output of the VCO according to a sequence of divide ratios to produce a divided signal having a frequency approximating the reference signal frequency. The phase comparator compares the phases of the divided signal and the reference signal and, in response to a difference, adapts the VCO to reduce the detected difference. The modulator provides a next value in the sequence of divide ratios by accumulating an error between a present value and an average value in the sequence of divide ratios, accumulating the accumulated error values, and determining the next value in the sequence of divide ratios such that the multiply-accumulated error values are maintained within finite bounds.
    Type: Grant
    Filed: November 14, 2003
    Date of Patent: July 4, 2006
    Assignee: Tektronix, Inc.
    Inventors: Daniel G. Knierim, David L. Knierim
  • Patent number: 7068087
    Abstract: A method and apparatus for an improved timer circuit and improved pulse width detection includes initiating a ramp timer and setting a timer latch output level substantially simultaneously in response to the occurrence of an input signal. The occurrence of the input signal also causes a counter to be enabled to count clock cycles. The ramp timer signal of the ramp timer is frozen (i.e., paused) by a timer control circuit, upon the occurrence of a first clock cycle following the enabling of the counter. The counter then counts a predetermined number of clock cycles after the ramp timer signal is frozen and, upon the occurrence of a last one of a predetermined number of clock cycles, generates a terminal count signal. Upon receiving the terminal count signal, the timer control circuit unfreezes ramp timer signal. The ramp timer runs until completion at which time the ramp timer generates an end of ramp control signal. The control signal is communicated to timer latch to reset timer latch output level.
    Type: Grant
    Filed: February 24, 2004
    Date of Patent: June 27, 2006
    Assignee: Tektronix, Inc.
    Inventors: John F. Stoops, Steven K. Sullivan
  • Patent number: 6980212
    Abstract: Apparatus in accordance with the subject invention maintains an exponentially decayed histogram of the counts of new pixels for each active channel, together with a running count of time and number of acquisitions. At regular intervals determined by a maximum time or by a minimum number of acquisitions it computes a new threshold for each active channel. This threshold will theoretically produce “N” nominally unusual waveforms per second where N is defined by a user “sensitivity” control. The raw histogram is smoothed to provide a stable “tail” of small probabilities. Once a threshold has been determined, subsequent waveforms with more than this number of new pixels are re-examined to determine the number of “really new” pixels. “Really new” pixels are defined as those that are not adjacent to pixels remaining from earlier acquisitions. Only those waveforms that have more “really new” pixels than a specified fraction of the basic threshold are reported as anomalies.
    Type: Grant
    Filed: April 17, 2002
    Date of Patent: December 27, 2005
    Assignee: Tektronix, Inc.
    Inventor: Peter J. Letts
  • Patent number: 6938172
    Abstract: A data transformation algorithm is selectively applied to each data vector as it enters the pipelined structure. In a selection step, the algorithm compares the bit value of the new data vector with the corresponding bit values of the preceding data vector, and sums the number of logic transitions. The transformation algorithm is applied to the new data vector only if it would reduce the resulting number of transitions, otherwise the data vector is propagated unmodified. Bit inversion is a data transformation algorithm according to the present invention that provides up to a 50% reduction in the number of logic transitions.
    Type: Grant
    Filed: January 18, 2002
    Date of Patent: August 30, 2005
    Assignee: Tektronix, Inc.
    Inventor: Michael S. Hagen
  • Patent number: 6917889
    Abstract: A test and measurement instrument acquires a signal from a device under test, displays that signal as a source waveform, and makes measurements on that source waveform with regard to a predetermined property or event. The test and measurement instrument employs the method of the subject invention for placing these measurements into a waveform and directly correlating a position in the measurement waveform to the same area on the source waveform where they were measured. Specifically, the subject invention displays the correlation of points on a source waveform and a measurement waveform without requiring the use of a common horizontal time scale. In one embodiment of the invention, the measurement waveform is a histogram and a pointer to a given location in the histogram causes identification of corresponding areas in the source waveform.
    Type: Grant
    Filed: February 26, 2003
    Date of Patent: July 12, 2005
    Assignee: Tektronix, Inc.
    Inventors: Benjamin A. Ward, John J. Pickerd
  • Patent number: 6895349
    Abstract: A gate comparator control panel, in accordance with the subject invention, allows a user to define up to four different gate regions that may exist on any of the live waveforms, maths waveforms, or REF waveforms. A menu for each gate controls the position of each gate and selects the source for the signal that is to be gated. All gates must be the same width. A high level application copies the gated region of a waveform into a REF memory. For example, Gate 1 would go into REF 1, gate 2 into REF2 and so on. A user-settable tolerance value is used to determine if difference between the waveforms of the gates reaches a point at which a violation is indicated. A master gate position control causes all gates to move by the same amount, thus maintaining a constant distance between them. A master gate width control causes all gates to change width.
    Type: Grant
    Filed: November 8, 2001
    Date of Patent: May 17, 2005
    Assignee: Tektronix, Inc.
    Inventors: John J. Pickerd, Paul H. Buckle
  • Patent number: 6895536
    Abstract: A logic analyzer according to the subject invention employs a bi-directional counter that can be incremented in response to detection of certain events, and decremented in response to detection of other, different, events. Both an overflow (incremented to a predetermined count) and an underflow (decremented to a predetermined count) can be tested by a trigger machine of the Logic Analyzer.
    Type: Grant
    Filed: September 23, 2002
    Date of Patent: May 17, 2005
    Assignee: Tektronix, Inc.
    Inventors: David A. Holaday, Gary K. Richmond
  • Patent number: 6892150
    Abstract: A combined analog and DSP trigger system for a digital storage oscilloscope (DSO) enables the DSO to real-time trigger on events in an input analog signal based on traditional trigger events in the input analog signal and/or predetermined anomalous events detected in digitized samples of the input analog signal. A processor receives the digitized samples at the input of an acquisition memory to detect the anomalous events and provides an event detect signal to the trigger system. Predetermined amounts of the digitized samples around the events are acquired in an acquisition memory for further processing and display.
    Type: Grant
    Filed: May 24, 2002
    Date of Patent: May 10, 2005
    Assignee: Tektronix, Inc.
    Inventors: John J. Pickerd, Que Thuy Tran
  • Patent number: 6876936
    Abstract: A method and apparatus for measuring inductance. The method and apparatus include processing current and voltage waveform data associated with an inductive device to determine edge and slope parameters for each of a plurality of current waveform data cycles. Furthermore, proportional magnetic flux and proportional magnetic current is determined from the acquired current waveform data and the voltage waveform data proximate determined edge regions of the waveform data. An inductance value of the inductive device may then be calculated from the proportional magnetic flux and proportional magnetic current.
    Type: Grant
    Filed: July 25, 2003
    Date of Patent: April 5, 2005
    Assignee: Tektronix, Inc.
    Inventors: P. E. Ramesh, Srikrishna Nadig
  • Patent number: 6853933
    Abstract: A method for identifying spectral impulses applies a window filter to an acquired waveform to produce a filtered waveform, and performs an FFT function on the filtered waveform to produce a spectrum of bins. An estimating window is located on the spectrum and centered on a target bin. Bins adjacent to the target bin are excluded and the remaining bins are used to form a noise estimate. The estimate is compared to the target bin and if the result exceeds a threshold value, a spectral impulse is identified.
    Type: Grant
    Filed: February 26, 2003
    Date of Patent: February 8, 2005
    Assignee: Tektronix, Inc.
    Inventors: Kan Tan, Mark L. Guenther
  • Patent number: 6847199
    Abstract: An instrument includes a probe providing a single signal path for conveying a signal from a circuit under test to the instrument. A receiver circuit within the instrument divides the path into an analog path and a digital path. The digital path includes a comparator for determining the logic state of the signal and producing a digital representation of the signal under test. The analog path includes a multiplexer to selectively couple one of a plurality of analog input signals to an output terminal for viewing on an oscilloscope. Preferably, the probe head includes a buffer amplifier to reduce loading on the circuit under test and to increase bandwidth of the signals conveyed along the test cable to the instrument. An electrically trimmable resistor is employed to terminate the transmission line of the test cable in its characteristic impedance in order to reduce reflections and maintain transmission bandwidth.
    Type: Grant
    Filed: February 11, 2003
    Date of Patent: January 25, 2005
    Assignee: Tektronix, Inc.
    Inventors: A. Roy Kaufman, Roland E. Andrews, Colin L. Shepard, William R. Mark, Lester L. Larson, Donald F. Murray
  • Patent number: 6836738
    Abstract: A first method for rendering an eye diagram synchronized to a recovered clock and based on a single shot acquisition of a digital storage oscilloscope, acquires a waveform and measures the timing of its edges. It then estimates the symbol rate of the waveform and derives clock signals in accordance with the edge timing and the estimated symbol rate. The waveform data is then sliced into frames with respect to the derived clock signals, and the frames are partially overlapped and aligned to form an eye diagram. In a second embodiment of the invention, the frames are aligned, without being overlapped, to form an eye diagram.
    Type: Grant
    Filed: March 14, 2003
    Date of Patent: December 28, 2004
    Assignee: Tektronix, Inc.
    Inventors: Kalev Sepp, John C. Calvin
  • Patent number: 6831588
    Abstract: A range recognizer applies acquired data to the inputs of a plurality of boundary comparators simultaneously, treating an entire range of values for the data as a single continuum which is partitioned by a series of internal boundaries that are monitonically increasing. Each boundary comparator compares the value of the data with its unique boundary value and provides the results to a single range encoder logic to generate a single binary word as an encoded result indicative of the comparison for the entire range. An upper boundary result of one boundary comparator is combined with a lower boundary result of an adjacent higher boundary comparator prior to input to the single range encoder logic. The result is a reduction In the number of output pins required on an integrated circuit (IC) for reporting the encoded result for a corresponding plurality of range recognizers.
    Type: Grant
    Filed: September 17, 2002
    Date of Patent: December 14, 2004
    Assignee: Tektronix, Inc.
    Inventor: Kevin C. Spisak
  • Patent number: 6832172
    Abstract: A jitter separation apparatus and method, based on spectrum analysis, separates deterministic jitter and random jitter using their spectral properties. Deterministic jitter is periodic and nature and exhibits a spectrum of impulses, whereas random jitter exhibits a broad, flat spectrum. A time domain histogram and a frequency domain histogram of the signal are investigated to obtain jitter components.
    Type: Grant
    Filed: May 16, 2002
    Date of Patent: December 14, 2004
    Assignee: Tektronix, Inc.
    Inventors: Benjamin A. Ward, Kan Tan, Mark L. Guenther
  • Patent number: 6832174
    Abstract: A system comprising a plurality of digital storage oscilloscopes (DSOs) in which each DSO acquires a common signal under test (SUT) according to respective clock signals having common frequency parameters and respective phase parameters such that a plurality of acquisition records may be interleaved to produce a higher effective resolution acquisition record.
    Type: Grant
    Filed: December 17, 2002
    Date of Patent: December 14, 2004
    Assignee: Tektronix, Inc.
    Inventors: Que Thuy Tran, David L. Kelly, Douglas A. Blegen
  • Patent number: 6812688
    Abstract: A test and measurement apparatus and method wherein a software implemented phase lock loop recovers a clock signal associated with the received data signal, the recovered clock signal being used to do TIE measurement, to generate eye diagram and to do mask testing.
    Type: Grant
    Filed: December 10, 2002
    Date of Patent: November 2, 2004
    Assignee: Tektronix, Inc.
    Inventors: Kan Tan, Benjamin A. Ward