Patents by Inventor Sartaj Chaudhary

Sartaj Chaudhary 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: 11796621
    Abstract: Techniques are disclosed related to determining a modulation quality measurement of a device-under-test (DUT). A modulated signal is received from a source a plurality of times, and each received modulated signal is transmitted to each of a first vector signal analyzer (VSA) and a second VSA. The first VSA and the second VSA demodulate the received modulated signals to produce first error vectors and second error vectors, respectively. A cross-correlation calculation is performed on the first error vectors and second error vectors of respective received modulated signals to produce a complex-valued cross-correlation measurement, and a real component of the cross-correlation measurement is averaged over the plurality of received modulated signals. A modulation quality measurement is determined based on the averaged cross-correlation measurement.
    Type: Grant
    Filed: November 12, 2021
    Date of Patent: October 24, 2023
    Assignee: National Instruments Corporation
    Inventor: Sartaj Chaudhary
  • Publication number: 20220065972
    Abstract: Techniques are disclosed related to determining a modulation quality measurement of a device-under-test (DUT). A modulated signal is received from a source a plurality of times, and each received modulated signal is transmitted to each of a first vector signal analyzer (VSA) and a second VSA. The first VSA and the second VSA demodulate the received modulated signals to produce first error vectors and second error vectors, respectively. A cross-correlation calculation is performed on the first error vectors and second error vectors of respective received modulated signals to produce a complex-valued cross-correlation measurement, and a real component of the cross-correlation measurement is averaged over the plurality of received modulated signals. A modulation quality measurement is determined based on the averaged cross-correlation measurement.
    Type: Application
    Filed: November 12, 2021
    Publication date: March 3, 2022
    Inventor: Sartaj Chaudhary
  • Patent number: 8611470
    Abstract: System and methods and memory media for identifying a rogue base station. A receiver captures an input signal that includes a mixture of the rogue station's transmission and the transmission of a victim base station. The victim station's transmission is removed from the mixture. A plurality of channel signals are extracted from the residual signal. The channel signals are analyzed which of them are “valid”, i.e., contain a GMSK-modulated GSM signal. The “valid” channel signals are low pass filtered and then analyzed to determine which of them corresponds to the beacon channel. Information identifying the rogue base station is extracted from the beacon channel.
    Type: Grant
    Filed: March 4, 2011
    Date of Patent: December 17, 2013
    Assignee: National Instruments Corporation
    Inventors: Utkarsh Gupta, Sartaj Chaudhary, Baijayanta Ray
  • Patent number: 8605828
    Abstract: A computer-implemented system and method for blind demodulation of an offset QPSK input signal, involving repeatedly performing a set of operations, including: (a) applying a phase correction to the input signal based on an estimate of a carrier phase offset of the input signal to obtain a first modified signal; (b) shifting a quadrature component of the first modified signal by half a symbol period relative to an inphase component to obtain a second modified signal; (c) extracting a first sequence of symbols from the second modified signal, where the extraction includes estimating a symbol timing offset from the second modified signal; (d) performing hard-decision demodulation on the first sequence of symbols to obtain a second sequence of reference symbols; (e) computing a phase difference between the first sequence of symbols and second sequence of reference symbols; and (f) updating the carrier phase offset estimate using the phase difference.
    Type: Grant
    Filed: February 17, 2012
    Date of Patent: December 10, 2013
    Assignee: National Instruments Corporation
    Inventors: Sartaj Chaudhary, Vijaya Yajnanarayana, I Zakir Ahmed
  • Publication number: 20130216005
    Abstract: A computer-implemented system and method for blind demodulation of an offset QPSK input signal, involving repeatedly performing a set of operations, including: (a) applying a phase correction to the input signal based on an estimate of a carrier phase offset of the input signal to obtain a first modified signal; (b) shifting a quadrature component of the first modified signal by half a symbol period relative to an inphase component to obtain a second modified signal; (c) extracting a first sequence of symbols from the second modified signal, where the extraction includes estimating a symbol timing offset from the second modified signal; (d) performing hard-decision demodulation on the first sequence of symbols to obtain a second sequence of reference symbols; (e) computing a phase difference between the first sequence of symbols and second sequence of reference symbols; and (f) updating the carrier phase offset estimate using the phase difference.
    Type: Application
    Filed: February 17, 2012
    Publication date: August 22, 2013
    Inventors: Sartaj Chaudhary, Vijaya Yajnanarayana, I Zakir Ahmed
  • Publication number: 20120027064
    Abstract: System and methods and memory media for identifying a rogue base station. A receiver captures an input signal that includes a mixture of the rogue station's transmission and the transmission of a victim base station. The victim station's transmission is removed from the mixture. A plurality of channel signals are extracted from the residual signal. The channel signals are analyzed which of them are “valid”, i.e., contain a GMSK-modulated GSM signal. The “valid” channel signals are low pass filtered and then analyzed to determine which of them corresponds to the beacon channel. Information identifying the rogue base station is extracted from the beacon channel.
    Type: Application
    Filed: March 4, 2011
    Publication date: February 2, 2012
    Inventors: Utkarsh Gupta, Sartaj Chaudhary, Baijayanta Ray