Patents by Inventor Karthik Ramasubramanian

Karthik Ramasubramanian 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).

  • Publication number: 20130016010
    Abstract: A GNSS receiver includes at least one buffer and at least one correlator block. The at least one buffer stores a plurality of samples corresponding to a received signal. The at least one correlator block includes a Doppler derotation block configured to perform Doppler derotation corresponding to at least one Doppler frequency on the plurality of samples, a register array configured to be loaded with the plurality of samples on Doppler derotation corresponding to a Doppler frequency of the at least one Doppler frequency, and a correlator engine configured to generate correlation results by correlating the plurality of samples in the register array with a plurality of code phases for at least one GNSS satellite. A presence of at least one GNSS satellite signal may be detected based on coherent accumulation and a non-coherent accumulation of the correlation results.
    Type: Application
    Filed: July 13, 2011
    Publication date: January 17, 2013
    Applicant: Texas Instruments Incorporated
    Inventors: Jasbir Singh Nayyar, Jawaharlal Tangudu, Karthik Ramasubramanian
  • Patent number: 8331898
    Abstract: An electronic circuit includes a receiver circuit (BSP) operable to perform coherent summations having a coherent summations time interval, and a power control circuit (2130) coupled to said receiver circuit (BSP) and operable to impress a power controlling duty cycle (TON, TOFF) on the receiver circuit (BSP) inside the coherent summations time interval. Other circuits, devices, systems, methods of operation and processes of manufacture are also disclosed.
    Type: Grant
    Filed: October 2, 2008
    Date of Patent: December 11, 2012
    Assignee: Texas Instruments Incorporated
    Inventors: Deric Wayne Waters, Karthik Ramasubramanian, Arun Raghupathy
  • Publication number: 20110250931
    Abstract: A personal navigation device configured to determine heading readings continuously using data from a sensor in the personal navigation device. Heading readings are selected corresponding to a periodic event. A representative heading is determined from the selected heading readings. When a portion of the selected heading readings has a value within a range of the representative heading, a static heading indicator is asserted to indicate the personal navigation device is moving in a static heading. The static heading indicator may be used to smooth an estimated trajectory of the personal navigation device.
    Type: Application
    Filed: April 1, 2011
    Publication date: October 13, 2011
    Inventors: Tarkesh Pande, Jaiganesh Balakrishnan, Deric Waters, Goutam Dutta, Jayawardan Janardhanan, Sthanunathan Ramakrishnan, Sandeep Rao, Karthik Ramasubramanian
  • Publication number: 20110187596
    Abstract: An electronic circuit (2250) for a satellite receiver (100, 2200). The electronic circuit (2250) includes a correlator circuit (2310) operable to supply a data signal including ephemeris data and a subsequent satellite time datum, and a data processor (2370, 2380) operable to infer satellite time TS from as few as one of the ephemeris data prior to the satellite time datum. Other circuits, devices, receivers, systems, processes of operation and processes of manufacture are also disclosed.
    Type: Application
    Filed: March 18, 2010
    Publication date: August 4, 2011
    Applicant: TEXAS INSTRUMENTS INCORPORATED
    Inventors: Sandeep Rao, Jawaharlal Tangudu, Karthik Ramasubramanian
  • Publication number: 20110068979
    Abstract: In at least some embodiments, an electronic device includes a navigation system receiver and a receiver motion estimator coupled to the navigation system receiver. The receiver motion estimator determines and provides a receiver motion estimation to the navigation system receiver to reduce complexity of a satellite signal search operation performed by the navigation system receiver.
    Type: Application
    Filed: September 24, 2010
    Publication date: March 24, 2011
    Applicant: TEXAS INSTRUMENTS INCORPORATED
    Inventors: Deric W. WATERS, Karthik RAMASUBRAMANIAN, Ravi BHAT
  • Publication number: 20110026651
    Abstract: Automatic gain control in a receiver. A method for controlling operating range of an analog-to-digital converter (ADC) by an automatic gain control circuit includes estimating a peak-to-average ratio corresponding to an analog signal from digital samples of the analog signal. The method includes determining a peak value corresponding to the analog signal based on the peak-to-average ratio. Further, the method includes maintaining magnitude of the analog signal at an input of the ADC and gain of the receiver based on the peak value.
    Type: Application
    Filed: February 2, 2010
    Publication date: February 3, 2011
    Applicant: Texas Instruments Incorporated
    Inventors: Bijoy BHUKANIA, Jawaharlal Tangudu, Karthik Ramasubramanian
  • Patent number: 7826341
    Abstract: In at least some embodiments, a system may comprise one or more devices configurable to communicate according to a first protocol that implements a first data packet, and one or more devices configurable to communicate according to a second protocol that implements a second data packet having a predetermined quadrature component. The one or more devices configurable to communicate according to the second protocol associate detection of the predetermined quadrature component with a function that is not supported by the one or more devices that communicate according to the first protocol.
    Type: Grant
    Filed: August 24, 2007
    Date of Patent: November 2, 2010
    Assignee: Texas Instruments Incorporated
    Inventors: Arndt Joseph Mueller, Karthik Ramasubramanian
  • Publication number: 20100171659
    Abstract: Embodiments of the invention provide a method for making information in the position engine (PE) available to the measurement engine (ME). With the right information the ME can reduce its power consumption, and improve its performance. Other circuits, devices, systems, methods of operation and processes of manufacture are also disclosed.
    Type: Application
    Filed: February 25, 2010
    Publication date: July 8, 2010
    Applicant: TEXAS INSTRUMENTS INCORPORATED
    Inventors: Deric Wayne Waters, Sandeep Rao, Karthik Ramasubramanian
  • Publication number: 20100119020
    Abstract: An aspect of the present invention detects the presence of interference by examining an input signal received on an input path, and blanks the receiver if interference is detected. Information contained in the input signal may be recovered otherwise. In an embodiment, the duty cycle of a jamming signal is determined by examining the input signal, and a threshold strength having a positive correlation with the duty cycle is determined. If the strength of the jamming signal during the on-interval (start and end of the interference in each cycle) is greater than the threshold strength, then only the receiver is blanked. Otherwise, no blanking is performed, and only the gain of an amplifier in the path from the input path to a baseband processor is reduced. According to another aspect, one or more cycles of the interference is used to detect the start of interference and the receiver is blanked when interference is present.
    Type: Application
    Filed: July 20, 2009
    Publication date: May 13, 2010
    Applicant: TEXAS INSTRUMENTS INCORPORATED
    Inventors: Bijoy Bhukania, Jawaharlal Tangudu, Karthik Ramasubramanian, Arun Raghupathy
  • Patent number: 7710856
    Abstract: In at least some embodiments, a system may comprise one or more devices configurable to communicate according to a first protocol that implements a first data packet, and one or more devices configurable to communicate according to a second protocol that implements a second data packet having a predetermined quadrature component. The one or more devices configurable to communicate according to the second protocol associate detection of the predetermined quadrature component with a function that is not supported by the one or more devices that communicate according to the first protocol.
    Type: Grant
    Filed: February 13, 2004
    Date of Patent: May 4, 2010
    Assignee: Texas Instruments Incorporated
    Inventors: Arndt Joseph Mueller, Karthik Ramasubramanian
  • Patent number: 7701839
    Abstract: A multi-rate interleaved frequency division multiple access (IFDMA) modulation scheme permits users to transmit at different data rates or to vary their data rates while providing frequency diversity and preserving low peak-to-average power ratios and orthogonality between user data rates. The modulation scheme allows user-specific data block and repetition sizes, as well as user-specific modulation codes. Code assignment rules are provided for maintaining orthogonality between the different user data rates. Block and phase ramp modulation codes can be used. Asynchronous transmissions by users are supported by ensuring that the length of the cyclic extension is sufficiently long to tolerate worst case relative signal arrival delays between users and the channel pulse response duration over the communication medium. The modulation scheme can be employed in wireless communication systems, such as cellular or paging systems.
    Type: Grant
    Filed: November 20, 2006
    Date of Patent: April 20, 2010
    Assignee: Motorola, Inc.
    Inventors: Vijay Nangia, Kevin Lynn Baum, Karthik Ramasubramanian
  • Patent number: 7583764
    Abstract: The present invention provides a system for obviating interference effects in packet detection within a wireless communications network. A plurality of reference signals is provided—a first of which corresponds to desired packets, and the remainder of which correspond to undesired packets or interference. A plurality of cross-correlation constructs corresponds, respectively, to the plurality of reference signals. Each cross-correlation construct correlates an incoming signal to a plurality of repetitions of its respective reference signal. An analysis construct compares output from each cross-correlation construct with other cross-correlation construct outputs, and with a threshold value, to determine which incoming signal corresponds to desired packet data. Once this incoming signal is identified, packets from the signal may be reliably received.
    Type: Grant
    Filed: May 26, 2006
    Date of Patent: September 1, 2009
    Assignee: Texas Instruments Incorporated
    Inventors: Karthik Ramasubramanian, Sthanunathan Ramakrishnan
  • Publication number: 20090168843
    Abstract: An electronic circuit includes a receiver circuit (BSP) operable to perform coherent summations having a coherent summations time interval, and a power control circuit (2130) coupled to said receiver circuit (BSP) and operable to impress a power controlling duty cycle (TON, TOFF) on the receiver circuit (BSP) inside the coherent summations time interval. Other circuits, devices, systems, methods of operation and processes of manufacture are also disclosed.
    Type: Application
    Filed: October 2, 2008
    Publication date: July 2, 2009
    Applicant: TEXAS INSTRUMENTS INCORPORATED
    Inventors: Deric Wayne Waters, Karthik Ramasubramanian, Arun Raghupathy
  • Publication number: 20070286067
    Abstract: In at least some embodiments, a system may comprise one or more devices configurable to communicate according to a first protocol that implements a first data packet, and one or more devices configurable to communicate according to a second protocol that implements a second data packet having a predetermined quadrature component. The one or more devices configurable to communicate according to the second protocol associate detection of the predetermined quadrature component with a function that is not supported by the one or more devices that communicate according to the first protocol.
    Type: Application
    Filed: August 24, 2007
    Publication date: December 13, 2007
    Applicant: TEXAS INSTRUMENTS INCORPORATED
    Inventors: Arndt Mueller, Karthik Ramasubramanian
  • Publication number: 20070274205
    Abstract: The present invention provides a system for obviating interference effects in packet detection within a wireless communications network. A plurality of reference signals is provided—a first of which corresponds to desired packets, and the remainder of which correspond to undesired packets or interference. A plurality of cross-correlation constructs corresponds, respectively, to the plurality of reference signals. Each cross-correlation construct correlates an incoming signal to a plurality of repetitions of its respective reference signal. An analysis construct compares output from each cross-correlation construct with other cross-correlation construct outputs, and with a threshold value, to determine which incoming signal corresponds to desired packet data. Once this incoming signal is identified, packets from the signal may be reliably received.
    Type: Application
    Filed: May 26, 2006
    Publication date: November 29, 2007
    Applicant: TEXAS INSTRUMENTS INCORPORATED
    Inventors: Karthik Ramasubramanian, Sthanunathan Ramakrishnan
  • Publication number: 20070091866
    Abstract: A multi-rate interleaved frequency division multiple access (IFDMA) modulation scheme permits users to transmit at different data rates or to vary their data rates while providing frequency diversity and preserving low peak-to-average power ratios and orthogonality between user data rates. The modulation scheme allows user-specific data block and repetition sizes, as well as user-specific modulation codes. Code assignment rules are provided for maintaining orthogonality between the different user data rates. Block and phase ramp modulation codes can be used. Asynchronous transmissions by users are supported by ensuring that the length of the cyclic extension is sufficiently long to tolerate worst case relative signal arrival delays between users and the channel pulse response duration over the communication medium. The modulation scheme can be employed in wireless communication systems, such as cellular or paging systems.
    Type: Application
    Filed: November 20, 2006
    Publication date: April 26, 2007
    Applicant: MOTOROLA, INC.
    Inventors: Vijay Nangia, Kevin Baum, Karthik Ramasubramanian
  • Patent number: 7139237
    Abstract: A multi-rate interleaved frequency division multiple access (IFDMA) modulation scheme permits users to transmit at different data rates or to vary their data rates while providing frequency diversity and preserving low peak-to-average power ratios and orthogonality between users at different data rates. The modulation scheme allows user-specific data block and repetition sizes, as well as user-specific modulation codes. Code assignment rules are provided for maintaining orthogonality between users having different data rates. Block and phase ramp modulation codes can be used. Asynchronous transmissions by users are supported by ensuring that the length of the cyclic extension is sufficiently long to tolerate worst case relative signal arrival delays between users and the channel pulse response duration over the communication medium. The modulation scheme can be employed in wireless communication systems, such as cellular or paging systems.
    Type: Grant
    Filed: September 24, 2001
    Date of Patent: November 21, 2006
    Assignee: Motorola, Inc.
    Inventors: Vijay Nangia, Kevin Lynn Baum, Karthik Ramasubramanian
  • Patent number: 7133474
    Abstract: A timing recovery scheme demarcates a complete range of inter-symbol interference free (ISI-free) sampling positions available in a cyclically extended symbol. The timing recovery scheme computes an ensemble correlation between the cyclic extension and the data part of symbols to estimate timing. The ensemble correlation function retains delay-spread and timing information by separately maintaining the correlation value for each sample position within the symbol duration and combines the correlation values for identical sample positions over an ensemble of symbols. In this manner, the scheme not only provides timing estimates, but can also provide estimates of the multipath delay-spread in a channel. The delay-spread estimates provide valuable information about the nature of the channel. A receiver can use this information, for example, to adjust the frequency-domain channel interpolation filter bandwidth in order to improve performance for the given channel condition.
    Type: Grant
    Filed: July 31, 2001
    Date of Patent: November 7, 2006
    Assignee: Motorola, Inc.
    Inventors: Karthik Ramasubramanian, Kevin Lynn Baum
  • Publication number: 20050180310
    Abstract: In at least some embodiments, a system may comprise one or more devices configurable to communicate according to a first protocol that implements a first data packet, and one or more devices configurable to communicate according to a second protocol that implements a second data packet having a predetermined quadrature component. The one or more devices configurable to communicate according to the second protocol associate detection of the predetermined quadrature component with a function that is not supported by the one or more devices that communicate according to the first protocol.
    Type: Application
    Filed: February 13, 2004
    Publication date: August 18, 2005
    Applicant: Texas Instruments Incorporated
    Inventors: Arndt Mueller, Karthik Ramasubramanian
  • Publication number: 20030026360
    Abstract: A timing recovery scheme demarcates a complete range of inter-symbol interference free (ISI-free) sampling positions available in a cyclically extended symbol. The timing recovery scheme computes an ensemble correlation between the cyclic extension and the data part of symbols to estimate timing. The ensemble correlation function retains delay-spread and timing information by separately maintaining the correlation value for each sample position within the symbol duration and combines the correlation values for identical sample positions over an ensemble of symbols. In this manner, the scheme not only provides timing estimates, but can also provide estimates of the multipath delay-spread in a channel. The delay-spread estimates provide valuable information about the nature of the channel. A receiver can use this information, for example, to adjust the frequency-domain channel interpolation filter bandwidth in order to improve performance for the given channel condition.
    Type: Application
    Filed: July 31, 2001
    Publication date: February 6, 2003
    Inventors: Karthik Ramasubramanian, Kevin Lynn Baum