Patents by Inventor Khurram Muhammad

Khurram Muhammad 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: 8600320
    Abstract: A mobile wireless communications device includes a portable housing, a transmitter carried by the portable housing and configured to modulate an input signal, and an adjustable impedance matching network coupled downstream from the transmitter. An antenna is coupled downstream from the adjustable impedance matching network, and a non-directional coupler is coupled between the adjustable impedance matching network and the antenna. A feedback receiver is coupled to the non-directional coupler to generate a feedback signal. A controller is configured to control the adjustable impedance matching network based upon the input signal and the feedback signal.
    Type: Grant
    Filed: February 8, 2013
    Date of Patent: December 3, 2013
    Assignee: BlackBerry Limited
    Inventor: Khurram Muhammad
  • Patent number: 8594233
    Abstract: A communications device may include In-phase (I) power amplifiers configured to generate I amplified signals, Quadrature (Q) power amplifiers configured to generate Q amplified signals, an I controller coupled to the I power amplifiers and configured to selectively enable some of the I power amplifiers, and a Q controller coupled to the Q power amplifiers and configured to selectively enable some of the Q power amplifiers. The communications device may also include a power combiner configured to combine the I amplified signals and the Q amplified signals in a combined amplified signal, and an antenna coupled to the power combiner.
    Type: Grant
    Filed: March 16, 2011
    Date of Patent: November 26, 2013
    Assignee: BlackBerry Limited
    Inventor: Khurram Muhammad
  • Patent number: 8594579
    Abstract: A mobile wireless communications device includes a transceiver, an auxiliary receiver and a controller. The transceiver includes a transmitter and a receiver. The transmitter upconverts a transmit baseband modulated signal and generates an RF modulated signal having a transmit impairment. The auxiliary receiver is coupled to the transmitter and downconverts the RF modulated signal and generates a receive baseband modulated signal having a receive impairment therein spectrally separated from the transmit impairment. The controller is coupled to the transmitter and the auxiliary receiver and estimates the transmit impairment while ignoring the receive impairment based on comparing the transmit baseband modulated signal with the receive baseband modulated signal. The controller generates an impairment compensation signal based upon the estimated transmit impairment.
    Type: Grant
    Filed: September 6, 2011
    Date of Patent: November 26, 2013
    Assignee: BlackBerry Limited
    Inventor: Khurram Muhammad
  • Patent number: 8588330
    Abstract: A communications device may include In-phase (I) power amplifiers configured to respectively generate I amplified signals, Quadrature (Q) power amplifiers configured to respectively generate Q amplified signals, I antennas respectively coupled to the I power amplifiers, and Q antennas respectively coupled to the Q power amplifiers. The communications device may also include an I controller coupled to the I power amplifiers and configured to selectively enable some of the I power amplifiers, and a Q controller coupled to the Q power amplifiers and configured to selectively enable some of the Q power amplifiers.
    Type: Grant
    Filed: March 16, 2011
    Date of Patent: November 19, 2013
    Assignee: BlackBerry Limited
    Inventor: Khurram Muhammad
  • Patent number: 8581760
    Abstract: A digital-to-analog converter is disclosed. The converter includes a gradient correction module that generates a correction term based on a model of gradient error. The correction term is then applied to the signal path in the digital domain or applied to the output of the digital-to-analog converter in the analog domain. The model used to generate the correction term is based on a vertical gradient error in the array of current source elements, which may be modelled and calibrated using a second-order polynomial. Further, a digital-to-analog converter having a Nyquist DAC and an oversampled DAC is disclosed. When the oversampled DAC is enabled, the resolution of the Nyquist DAC may be increased while slowing the conversion rate.
    Type: Grant
    Filed: October 3, 2011
    Date of Patent: November 12, 2013
    Assignee: BlackBerry Limited
    Inventors: Khurram Muhammad, Tajinder Manku, Semyon Lebedev
  • Patent number: 8553802
    Abstract: A communications device may include an In-phase (I) power amplifier configured to generate an I amplified signal, a Quadrature (Q) power amplifier configured to generate a Q amplified signal, an I digital-to-analog converter (DAC) configured to generate an I signal, and a Q DAC configured to generate a Q signal. The communications device may also include an I power supply circuit coupled to the I power amplifier and to the I DAC and configured to cause the I power amplifier to modulate an I carrier signal into the I amplified signal based upon the I signal, a Q power supply circuit coupled to the Q power amplifier and to the Q DAC and configured to cause the Q power amplifier to modulate a Q carrier signal into the Q amplified signal based upon the Q signal, and at least one antenna coupled to the I and Q power amplifiers.
    Type: Grant
    Filed: March 16, 2011
    Date of Patent: October 8, 2013
    Assignee: Blackberry Limited
    Inventor: Khurram Muhammad
  • Patent number: 8542616
    Abstract: A novel mechanism for simultaneous multiple signal reception and transmission using frequency multiplexing and shared processing. Multiple RF signals, which may be of various wireless standards, are received using one or more shared processing blocks thereby significantly reducing chip space and power requirements. Shared components include local oscillators, analog to digital converters, digital RX processing and digital baseband processing. In operation, multiple RX front end circuits, one for each desired wireless signal, generate a plurality of IF signals that are frequency multiplexed and combined to create a single combined IF signal. The combined IF signal is processed by a shared processing block. Digital baseband processing is performed on each receive signal to generate respective data outputs. Further, simultaneous full-duplex transmission and reception is performed using a single local oscillator.
    Type: Grant
    Filed: October 14, 2008
    Date of Patent: September 24, 2013
    Assignee: Texas Instruments Incorporated
    Inventors: Robert B. Staszewski, Khurram Muhammad, Dirk Leipold
  • Publication number: 20130208827
    Abstract: A communications device includes a plurality of wireless transmitters operable at different respective frequencies and each configured to generate respective IQ signals having an initial IQ imbalance. An auxiliary receiver is coupled to a given wireless transmitter. In addition, a controller is configured to apply predistortion to the each wireless transmitter of the plurality thereof based upon the initial IQ imbalance generated by the given wireless transmitter to reduce the initial IQ imbalance in each wireless transmitter.
    Type: Application
    Filed: February 15, 2012
    Publication date: August 15, 2013
    Applicant: Research In Motion Limited
    Inventors: Khurram MUHAMMAD, Oleksiy KRAVETS
  • Publication number: 20130208770
    Abstract: A communications device includes a plurality of wireless transmitters operable at different respective frequencies and each configured to generate respective IQ signals having an initial IQ imbalance. The communications device also includes a frequency tunable auxiliary receiver, and a controller. The controller is configured to selectively couple a given wireless transmitter to the frequency tunable auxiliary receiver and tune the frequency tunable auxiliary receiver to a frequency of the given wireless transceiver, and apply predistortion to the given wireless transmitter based upon the initial IQ imbalance to reduce the initial IQ imbalance.
    Type: Application
    Filed: February 15, 2012
    Publication date: August 15, 2013
    Applicant: Research In Motion Limited
    Inventors: Khurram Muhammad, Oleksiy Kravets
  • Publication number: 20130195152
    Abstract: A communications device includes a baseband input to receive a baseband signal. A transmitter is coupled to the baseband input and generates a transmit signal based upon the baseband signal, the transmit signal having an initial transmit impairment. An auxiliary receiver is coupled to the transmitter and generates a receive signal having a receive impairment therein resulting from the initial transmit impairment. A controller determines a power of the baseband signal by integrating a product of the receive signal and a complex conjugate of the baseband signal, and determines a power of the receive signal by integrating a product of the baseband signal and the receive signal. The controller also determines the initial transmit impairment based upon the power of the baseband signal and the receive signal, and generates a transmit impairment compensation signal based upon the initial transmit impairment.
    Type: Application
    Filed: January 27, 2012
    Publication date: August 1, 2013
    Applicant: Research In Motion Limited
    Inventor: Khurram Muhammad
  • Publication number: 20130196719
    Abstract: A mobile wireless communications device may include a portable housing, and a supply modulator carried by the portable housing. The supply modulator may include an output node, a linear amplifier coupled to the output node, and a switching amplifier also coupled to the output node. The switching amplifier may include at least one sensing transistor configured to sense current output from the linear amplifier and generate a drive voltage, and a hysteretic comparator coupled to the at least one sensing transistor and configured to be driven by the drive voltage. The mobile wireless communications device may also include a radio frequency (RF) power amplifier coupled to the output node of the supply modulator, and a wireless transceiver carried by the portable housing and coupled to the RF power amplifier.
    Type: Application
    Filed: January 27, 2012
    Publication date: August 1, 2013
    Applicant: Research In Motion Limited
    Inventors: Khurram MUHAMMAD, Seong-Ryong Ryu
  • Publication number: 20130196716
    Abstract: A communications device includes a housing and a wireless transceiver and processor carried by the housing and operative with each other. An input screen is carried by the housing and comprises a plurality of spaced transceivers positioned at the input screen and connected to the processor and each configured to transmit a millimeter wave RF signal and receive reflected signals from an object positioned close to the input screen. The processor is configured to determine the location of the object relative to the input screen based on the reflected signals received at each transceiver.
    Type: Application
    Filed: January 27, 2012
    Publication date: August 1, 2013
    Applicant: Research In Motion Limited
    Inventor: Khurram MUHAMMAD
  • Patent number: 8494468
    Abstract: A mobile wireless communications device may include a portable housing, and a supply modulator carried by the portable housing. The supply modulator may include an output node, a linear amplifier coupled to the output node, and a switching amplifier also coupled to the output node. The switching amplifier may include at least one sensing transistor configured to sense current output from the linear amplifier and generate a drive voltage, and a hysteretic comparator coupled to the at least one sensing transistor and configured to be driven by the drive voltage. The mobile wireless communications device may also include a radio frequency (RF) power amplifier coupled to the output node of the supply modulator, and a wireless transceiver carried by the portable housing and coupled to the RF power amplifier.
    Type: Grant
    Filed: January 27, 2012
    Date of Patent: July 23, 2013
    Assignee: Research In Motion Limited
    Inventors: Khurram Muhammad, Seong-Ryong Ryu
  • Publication number: 20130176011
    Abstract: Provided is an apparatus comprising a DCDC converter having a plurality of converter modules each configured to convert current from a first voltage level to another voltage form. In accordance with an embodiment of the disclosure, the converter modules are configured to be dynamically enabled or disabled such that only each converter module that has been enabled converts current for an output of the DCDC converter. Any inefficiency that would have been introduced by converter modules that are not needed are mitigated or eliminated altogether. The effect is that efficiency can be improved during low load conditions when there is no need to enable all of the converter modules.
    Type: Application
    Filed: January 11, 2012
    Publication date: July 11, 2013
    Applicant: RESEARCH IN MOTION LIMITED
    Inventor: Khurram MUHAMMAD
  • Patent number: 8478213
    Abstract: Various embodiments include a method for controlling power in a transmitter, the method comprising measuring an indication of an output power of the transmitter, comparing a first value corresponding to the indication of the output power to a second value corresponding to a desired output power; and adjusting a bias of at least one component in the transmitter in order to bring the output power closer to the desired output power. Embodiments also include various methods, systems and apparatus.
    Type: Grant
    Filed: October 14, 2011
    Date of Patent: July 2, 2013
    Assignee: Research In Motion Limited
    Inventor: Khurram Muhammad
  • Patent number: 8462030
    Abstract: The present invention is directed to a programmable loop filter, a method of programming the same and a sigma delta analog-to-digital converter (ADC) incorporating the programmable loop filter or the method. In one embodiment, the programmable loop filter includes: (1) a configurable filter structure containing selectably interconnectable alternative filter elements and (2) a configuration controller coupled to the configurable filter structure and operable to interconnect at least a selected one of the filter elements to determine a transfer characteristic of the configurable filter structure and set an operating condition of the sigma delta ADC.
    Type: Grant
    Filed: April 27, 2004
    Date of Patent: June 11, 2013
    Assignee: Texas Instruments Incorporated
    Inventor: Khurram Muhammad
  • Patent number: 8428526
    Abstract: A system and method for tuning baseband filters in wireless transceivers. A method comprises coupling a radio frequency (RF) signal generated by the wireless transmitter at an input of a wireless receiver, the RF signal having a desired frequency, measuring a magnitude of the coupled RF signal at an output of an analog-to-digital converter at an output of an analog baseband filter, wherein the magnitude is measured at the desired frequency, and adjusting a corner frequency of the analog baseband filter in response to the determining that the measured magnitude differs from a specified value.
    Type: Grant
    Filed: March 17, 2008
    Date of Patent: April 23, 2013
    Assignee: Texas Instruments Incorporated
    Inventors: Yongtao Wang, Khurram Muhammad
  • Publication number: 20130095777
    Abstract: Various embodiments include a method for controlling power in a transmitter, the method comprising measuring an indication of an output power of the transmitter, comparing a first value corresponding to the indication of the output power to a second value corresponding to a desired output power; and adjusting a bias of at least one component in the transmitter in order to bring the output power closer to the desired output power. Embodiments also include various methods, systems and apparatus.
    Type: Application
    Filed: October 14, 2011
    Publication date: April 18, 2013
    Inventor: Khurram Muhammad
  • Publication number: 20130082853
    Abstract: A digital-to-analog converter is disclosed. The converter includes a gradient correction module that generates a correction term based on a model of gradient error. The correction term is then applied to the signal path in the digital domain or applied to the output of the digital-to-analog converter in the analog domain. The model used to generate the correction term is based on a vertical gradient error in the array of current source elements, which may be modelled and calibrated using a second-order polynomial. Further, a digital-to-analog converter having a Nyquist DAC and an oversampled DAC is disclosed. When the oversampled DAC is enabled, the resolution of the Nyquist DAC may be increased while slowing the conversion rate.
    Type: Application
    Filed: October 3, 2011
    Publication date: April 4, 2013
    Inventors: Khurram MUHAMMAD, Tajinder Manku, Semyon Lebedev
  • Publication number: 20130058387
    Abstract: A mobile wireless communications device includes a transceiver comprising a transmitter and a receiver, an auxiliary receiver, and a controller. The transmitter is configured to upconvert a transmit baseband modulated signal and generate an RF modulated signal having a transmit impairment. The auxiliary receiver is configured to downconvert the RF modulated signal and generate a receive baseband modulated signal having the transmit impairment. The auxiliary receiver is selectively configured to operate based on a control signal in a single-mixer mode when the transmitter is selectively configured to operate in a dual-mixer mode, and in the dual-mixer mode when the transmitter is selectively configured to operate in the single-mixer mode. The controller is configured to compare the transmit baseband modulated signal to the transmit impairment to determine an error difference therebetween, and generate the control signal based on the error difference.
    Type: Application
    Filed: September 6, 2011
    Publication date: March 7, 2013
    Applicant: Research in Motion Limited
    Inventor: KHURRAM MUHAMMAD