Patents by Inventor John J. Pickerd

John J. Pickerd has filed for patents to protect the following inventions. This listing includes patent applications that are pending as well as patents that have already been granted by the United States Patent and Trademark Office (USPTO).

  • Patent number: 10345339
    Abstract: Embodiments of the present invention provide techniques and methods for improving signal-to-noise ratio (SNR) when averaging two or more data signals by finding a group delay between the signals and using it to calculate an averaged result. In one embodiment, a direct average of the signals is computed and phases are found for the direct average and each of the data signals. Phase differences are found between each signal and the direct average. The phase differences are then used to compensate the signals. Averaging the compensated signals provides a more accurate result than conventional averaging techniques. The disclosed techniques can be used for improving instrument accuracy while minimizing effects such as higher-frequency attenuation. For example, in one embodiment, the disclosed techniques may enable a real-time oscilloscope to take more accurate S parameter measurements.
    Type: Grant
    Filed: April 29, 2016
    Date of Patent: July 9, 2019
    Assignee: Tektronix, Inc.
    Inventors: Kan Tan, John J. Pickerd
  • Patent number: 10330700
    Abstract: A signal acquisition probe stores compressed or compressed and filtered time domain data samples representing at least one of an impulse response or step response characterizing the signal acquisition probe. The compressed or compressed and filtered time domain data samples of the impulse response or the step response are provided to a signal measurement instrument for compensating the signal measurement instrument for the impulse or step response of the signal measurement instrument.
    Type: Grant
    Filed: August 18, 2015
    Date of Patent: June 25, 2019
    Assignee: Tektronix, Inc.
    Inventors: Richard A. Booman, John J. Pickerd
  • Patent number: 10274520
    Abstract: A test and measurement instrument, including a splitter configured to split an input signal into two split input signals and output each split input signal onto a separate path and a combiner configured to receive and combine an output of each path to reconstruct the input signal. Each path includes an amplifier configured to receive the split input signal and to compress the split input signal with a sigmoid function, a digitizer configured to digitize an output of the amplifier; and at least one processor configured to apply an inverse sigmoid function on the output of the digitizer.
    Type: Grant
    Filed: September 30, 2015
    Date of Patent: April 30, 2019
    Assignee: Tektronix, Inc.
    Inventors: John J. Pickerd, Kan Tan
  • Publication number: 20190103999
    Abstract: A continuously or step variable passive noise filter for removing noise from a signal received from a DUT added by a test and measurement instrument channel. The noise filter may include, for example, a splitter splits a signal into at least a first split signal and a second split signal. A first path receives the first split signal and includes a variable attenuator and/or a variable delay line which may be set based on the channel response of the DUT which is connected. The variable attenuator and/or the variable delay line may be continuously or stepped variable, as will be discussed in more detail below. A second path is also included to receive the second split signal and a combiner combines a signal from the first path and a signal from the second path into a combined signal.
    Type: Application
    Filed: August 29, 2018
    Publication date: April 4, 2019
    Applicant: Tektronix, Inc.
    Inventors: John J. Pickerd, Kan Tan, Pirooz Hojabri
  • Patent number: 10145874
    Abstract: A method for determining scattering parameters of a device under test using a real-time oscilloscope. The method includes calculating a reflection coefficient of each port of a device under test with N ports, wherein N is greater than one, based on a first voltage measured by the real-time oscilloscope when a signal is generated from a signal generator. The method also includes determining an insertion loss coefficient of each port of the device under test, including calculating the insertion loss coefficient of the port of the device under test to be measured based on a second voltage measured by the real-time oscilloscope when a signal is generated from a signal generator.
    Type: Grant
    Filed: March 30, 2015
    Date of Patent: December 4, 2018
    Assignee: Tektronix, Inc.
    Inventors: Kan Tan, John J. Pickerd
  • Patent number: 10097222
    Abstract: Disclosed is a noise filter. The noise filter includes an input port to receive an analog signal. The noise filter further includes a multiplexer coupled to the input port. The multiplexer separates the analog signal into a plurality of frequency bands. The frequency bands include a high frequency band and a low frequency band. The noise filter also includes a low-band variable attenuator coupled to the multiplexer. The low-band variable attenuator adjustably attenuates the low frequency band relative to the high frequency band.
    Type: Grant
    Filed: September 29, 2017
    Date of Patent: October 9, 2018
    Assignee: Tektronix, Inc.
    Inventors: John J. Pickerd, Pirooz Hojabri
  • Patent number: 10073750
    Abstract: A serial data link measurement and simulation system for use on a test and measurement instrument presents on a display device. A main menu having elements representing a measurement circuit, a simulation circuit and a transmitter. The main menu includes processing flow lines pointing from the measurement circuit to the transmitter and from the transmitter to the simulation circuit. The main menu includes a source input to the measurement circuit and one or more test points from which waveforms may be obtained. The simulation circuit includes a receiver. The measurement and simulation circuits are defined by a user, and the transmitter is common to both circuits so all aspects of the serial data link system are tied together.
    Type: Grant
    Filed: February 4, 2013
    Date of Patent: September 11, 2018
    Assignee: Tektronix, Inc.
    Inventors: John J. Pickerd, Kan Tan, Kalev Sepp, Sarah R. Boen
  • Publication number: 20180123626
    Abstract: Disclosed is a noise filter. The noise filter includes an input port to receive an analog signal. The noise filter further includes a multiplexer coupled to the input port. The multiplexer separates the analog signal into a plurality of frequency bands. The frequency bands include a high frequency band and a low frequency band. The noise filter also includes a low-band variable attenuator coupled to the multiplexer. The low-band variable attenuator adjustably attenuates the low frequency band relative to the high frequency band.
    Type: Application
    Filed: September 29, 2017
    Publication date: May 3, 2018
    Applicant: Tektronix, Inc.
    Inventors: John J. Pickerd, Pirooz Hojabri
  • Patent number: 9933458
    Abstract: A test and measurement instrument including a splitter configured to split an input signal into at least two split signals, at least two harmonic mixers configured to mix an associated split signal with an associated harmonic signal to generate an associated mixed signal, at least two digitizers configured to digitize the associated mixed signal, at least two MIMO polyphase filter arrays configured to filter the associated digitized mixed signal of an associated digitizer of the at least two digitizers, at least two pairs of band separation filters configured to receive the associated digitized mixed signals from each of the MIMO polyphase filter arrays and output a low band of the input signal and a high band of the input signal based on a time different between the at least two digitizers and a phase drift of a local oscillator, and a combiner configured to combine the low band of the input signal and the high band of the input signal to form a reconstructed input signal.
    Type: Grant
    Filed: March 31, 2015
    Date of Patent: April 3, 2018
    Assignee: Tektronix, Inc.
    Inventors: John J. Pickerd, Kan Tan
  • Publication number: 20180026816
    Abstract: Systems and methods directed towards reducing noise introduced into a signal when processing the signal are discussed herein. In embodiments a signal may initially be split by a multiplexer into two or more frequency bands. Each of the frequency bands can then be forwarded through an assigned channel. One or more channels may include an amplifier to independently boost the signal band assigned to that channel prior to a noise source within the assigned channel. This results in boosting the signal band relative to noise introduced by the noise source. In some embodiments, a filter may also be implemented in one or more of the channels to remove noise from the channel that is outside the bandwidth of the signal band assigned to that channel. Additional embodiments may be described and/or claimed herein.
    Type: Application
    Filed: June 8, 2017
    Publication date: January 25, 2018
    Inventors: John J. Pickerd, Kan Tan, Pirooz Hojabri
  • Publication number: 20170328932
    Abstract: Disclosed are systems and methods related to a noise reduction device employing an analog filter and a corresponding inverse digital filter. The combination and placement of the filters within the systems aids in reducing noise introduced by processing the signal. In some embodiments, the combination of filters may also provide for increased flexibility when de-embedding device under test (DUT) link attenuation at higher frequencies. Further, the filters are adjustable, via a controller, to obtain an increased signal to noise ratio (SNR) relative to a signal channel lacking the combination of filters. Additional embodiments may be disclosed and/or claimed herein.
    Type: Application
    Filed: December 30, 2016
    Publication date: November 16, 2017
    Inventors: Barton T. Hickman, John J. Pickerd, Pirooz Hojabri, Patrick Satarzadeh, Khadar Baba Shaik
  • Publication number: 20170292977
    Abstract: Disclosed is a mechanism for reducing noise caused by an analog to digital conversion in a test and measurement system. An adaptive linear filter is generated based on a converted digital signal and measured signal noise. The adaptive linear filter includes a randomness suppression factor for alleviating statistical errors caused by a comparison of a signal circularity coefficient and a noise circularity coefficient in the adaptive linear filter. The adaptive linear filter is applied to the digital signal along with a stomp filter and a suppression clamp filter. The digital signal may be displayed in a complex frequency domain along with depictions of the adaptive linear filter frequency response and corresponding circularity coefficients. The display may be animated to allow a user to view the signal and/or filters in the frequency domain at different times.
    Type: Application
    Filed: March 31, 2017
    Publication date: October 12, 2017
    Inventors: John J. Pickerd, Kan Tan
  • Patent number: 9772391
    Abstract: A test and measurement system including a test and measurement instrument, a probe connected to the test and measurement instrument, a device under test connected to the probe, at least one memory configured to store parameters for characterizing the probe, a user interface and a processor. The user interface is configured to receive a nominal source impedance of the device under test. The processor is configured to receive the parameters for characterizing the probe from the memory and the nominal source impedance of the device under test from the user interface and to calculate an equalization filter using the parameters for characterizing the probe and nominal source impedance from the user interface.
    Type: Grant
    Filed: January 24, 2014
    Date of Patent: September 26, 2017
    Assignee: Tektronix, Inc.
    Inventors: John J. Pickerd, William A. Hagerup, William Q. Law
  • Publication number: 20170168092
    Abstract: Embodiments of the present invention provide techniques and methods for improving signal-to-noise ratio (SNR) when averaging two or more data signals by finding a group delay between the signals and using it to calculate an averaged result. In one embodiment, a direct average of the signals is computed and phases are found for the direct average and each of the data signals. Phase differences are found between each signal and the direct average. The phase differences are then used to compensate the signals. Averaging the compensated signals provides a more accurate result than conventional averaging techniques. The disclosed techniques can be used for improving instrument accuracy while minimizing effects such as higher-frequency attenuation. For example, in one embodiment, the disclosed techniques may enable a real-time oscilloscope to take more accurate S parameter measurements.
    Type: Application
    Filed: April 29, 2016
    Publication date: June 15, 2017
    Inventors: Kan Tan, John J. Pickerd
  • Publication number: 20170089954
    Abstract: A test and measurement instrument, including a splitter configured to split an input signal into two split input signals and output each split input signal onto a separate path and a combiner configured to receive and combine an output of each path to reconstruct the input signal. Each path includes an amplifier configured to receive the split input signal and to compress the split input signal with a sigmoid function, a digitizer configured to digitize an output of the amplifier; and at least one processor configured to apply an inverse sigmoid function on the output of the digitizer.
    Type: Application
    Filed: September 30, 2015
    Publication date: March 30, 2017
    Inventors: John J. Pickerd, Kan Tan
  • Patent number: 9599639
    Abstract: A method of preventing inter-system interference while acquiring waveforms in a test and measurement instrument with variation in a device under test system S-parameters. The method includes receiving a waveform from a device under test at the test and measurement instrument, digitizing the waveform, identifying portions of the digitized waveform with different S-parameter characteristics, separating the identified portions of the digitized waveform into different waveforms, and displaying the different waveforms to a user.
    Type: Grant
    Filed: November 14, 2013
    Date of Patent: March 21, 2017
    Assignee: Tektronix, Inc.
    Inventor: John J. Pickerd
  • Publication number: 20160291056
    Abstract: A test and measurement instrument including a splitter configured to split an input signal into at least two split signals, at least two harmonic mixers configured to mix an associated split signal with an associated harmonic signal to generate an associated mixed signal, at least two digitizers configured to digitize the associated mixed signal, at least two MIMO polyphase filter arrays configured to filter the associated digitized mixed signal of an associated digitizer of the at least two digitizers, at least two pairs of band separation filters configured to receive the associated digitized mixed signals from each of the MIMO polyphase filter arrays and output a low band of the input signal and a high band of the input signal based on a time different between the at least two digitizers and a phase drift of a local oscillator, and a combiner configured to combine the low band of the input signal and the high band of the input signal to form a reconstructed input signal.
    Type: Application
    Filed: March 31, 2015
    Publication date: October 6, 2016
    Inventors: John J. Pickerd, Kan Tan
  • Patent number: 9432042
    Abstract: A test and measurement instrument including a splitter configured to split an input signal having a particular bandwidth into a plurality of split signals, each split signal including substantially the entire bandwidth of the input signal; a plurality of harmonic mixers, each harmonic mixer configured to mix an associated split signal of the plurality of split signals with an associated harmonic signal to generate an associated mixed signal; and a plurality of digitizers, each digitizer configured to digitize a mixed signal of an associated harmonic mixer of the plurality of harmonic mixers. A first-order harmonic of at least one harmonic signal associated with the harmonic mixers is different from an effective sample rate of at least one of the digitizers.
    Type: Grant
    Filed: March 28, 2014
    Date of Patent: August 30, 2016
    Assignee: TEKTRONIX, INC.
    Inventors: Daniel G. Knierim, John J. Pickerd
  • Patent number: 9407280
    Abstract: A harmonic time interleave (HTI) system, including a reference signal, a first summing component to produce a summed reference signal, a de-interleave block to receive an input signal and output a plurality of de-interleaved input signals, a plurality of digital-to-analog converters, each digital-to-analog converter configured to receive a corresponding one of a plurality of de-interleaved input signals and to output a corresponding analog signal, a plurality of mixing components, each mixing component configured to receive the summed reference signal and an analog signal from a corresponding of the plurality of digital-to-analog converters, and to output a corresponding mixed signal, and a second summing component configured to receive the mixed signal from each of the corresponding mixing components and to produce a substantially full-bandwidth analog signal representation of the input signal.
    Type: Grant
    Filed: April 27, 2015
    Date of Patent: August 2, 2016
    Assignee: TEKTRONIX, INC.
    Inventor: John J. Pickerd
  • Publication number: 20160047842
    Abstract: A signal acquisition probe stores compressed or compressed and filtered time domain data samples representing at least one of an impulse response or step response characterizing the signal acquisition probe. The compressed or compressed and filtered time domain data samples of the impulse response or the step response are provided to a signal measurement instrument for compensating the signal measurement instrument for the impulse or step response of the signal measurement instrument.
    Type: Application
    Filed: August 18, 2015
    Publication date: February 18, 2016
    Inventors: Richard A. Booman, John J. Pickerd