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Challa, CA

Deepak Challa, San Diego, CA US

Patent application numberDescriptionPublished
20100057454SYSTEM AND METHOD FOR ECHO CANCELLATION - An echo canceller for improved recognition and removal of an echo from a communication device. The echo canceller can dynamically reduce echo using an improved energy estimator and an improved adaptive filter. The improved energy estimator can determine if conversation is in a single talk period or a double talk period based on the combined energy of both the near end background noise and speech. The improved adaptive filter can reduce echo by dynamically changing adaptation speed or step size. In double talk, the adaptive filter(s) can dynamically slow-down or stop adaptation. In single talk, the filter can dynamically increase the speed of adaptation to improve accuracy, or decrease adaptation speed for stability.03-04-2010

Madhusudan Challa, San Francisco, CA US

Patent application numberDescriptionPublished
20120005339UTILIZING CAPTURED IP PACKETS TO DETERMINE OPERATIONS PERFORMED ON PACKETS BY A NETWORK DEVICE - Methods and systems for utilizing captured packets to determine the operations performed on packets by a network device are described. One or more packets are captured and forwarded through the network device. Operations performed on the captured IP packets are logged.01-05-2012

Nagesh Challa, Saratoga, CA US

Patent application numberDescriptionPublished
20090194591System, method and apparatus for placing and updating information in a personal digital electronic device for communication to a bar code scanner - A personal digital electronic device is provided with two enhancements, namely (a) an IR receiver and associated circuitry and software/firmware for mimicking a laser scanner operation, so that information existing in physical form with an associated bar code may be entered into the personal digital electronic device at the point of transaction; and (b) a radio receiver and associated circuitry and software/firmware to receive and process RDS feeds, so that offers, coupons and promotions embedded in the RDS feeds may be detected and used to place or update information on the personal digital electronic device. The personal digital electronic device is enabled for communication with a bar code scanner preferably using the “active light” communication technology.08-06-2009
20110215162Method and Apparatus for Communicating Information From a Mobile Digital Device to a Bar Code Scanner - Techniques are described for facilitating the reliable communication of information to bar code scanners from mobile digital devices, thereby enabling mobile digital devices to easily access the current commercial infrastructure. These techniques may be used to access many other goods and services in addition to conventional commercial services. The core enabling technology is the use of various elements commonly found on mobile digital devices to provide light that simulate a reflection of a scanning beam being moved across a static bar code image, and to confirm completion of the scan. The control system may interpret the light provided by the mobile digital device as merely a conventional identification type bar code, although the control system may be enhanced to identify and receive other types of information, including identity and credit information.09-08-2011

Patent applications by Nagesh Challa, Saratoga, CA US

Raghu Challa, San Diego, CA US

Patent application numberDescriptionPublished
20080226001ADJACENT CHANNEL INTERFERENCE DETECTION FOR WIRELESS COMMUNICATION - Techniques for detecting adjacent channel interference (ACI) in a wireless communication system are described. Input inphase (I) and quadrature (Q) samples are filtered with a first filter response to obtain filtered I and Q samples. The first filter response is designed to pass signal in an adjacent frequency channel while suppressing signals in a desired frequency channel and non-adjacent frequency channels. Correlations of the filtered I and Q samples are determined. The presence of ACI is detected based on the correlations of the filtered I and Q samples and the power of the input I and Q samples. If ACI is present, then whether the ACI is from a higher frequency channel or a lower frequency channel is determined based on one or more of the correlations. The input I and Q samples are filtered with a second filter response that is adjusted based on the detection of ACI.09-18-2008
20090003427BURSTY INTERFERENCE SUPPRESSION FOR COMMUNICATIONS RECEIVERS - Techniques are provided for suppressing interference by taking into account the possible bursty nature of co-channel interference in a communication system. In an aspect, interference levels are separately computed for first and second data portions of a desired signal. The computed interference levels may be used to scale the corresponding data portions for subsequent processing.01-01-2009
20090245192Reconfigurable Wireless Modem Sub-Circuits To Implement Multiple Air Interface Standards - A flexible and reconfigurable digital system (for example, a wireless modem) includes a set of sub-circuits. Each sub-circuit includes a task manager and an amount of configurable hardware circuitry for performing a type of operation on a data stream. The task manager of a sub-circuit can configure and control the configurable hardware of the sub-circuit. A central processor configures and orchestrates operation of the sub-circuits by maintaining a set of task lists in a tightly coupled memory. Each task list includes task instructions for a corresponding sub-circuit. The task manager of a sub-circuit reads task instructions from its task list and controls its associated hardware circuitry as directed by the instructions. A timestamp task instruction and a push task instruction and the task list architecture allow modem sub-circuits to be easily reconfigured to operate in accordance with either a first air interface standard or a second air interface standard.10-01-2009
20090245423De-Interlever That Simultaneously Generates Multiple Reorder Indices - A de-interleaver involves logic that receives a seed and that simultaneously generates from the seed a plurality of reorder indices. The plurality of reorder indices is usable for de-interleaving an incoming stream of interleaved code bits. Each plurality of simultaneously generated reorder indices generated corresponds to a set of simultaneously received code bits in the incoming stream. The reorder indices are converted into physical addresses in parallel and these physical addresses are used to store the set of code bits into a memory. Code bits for multiple sub-packets of different sub-packet sizes are typically present in memory at the same time. The code bits are then read out of memory to form an outgoing stream of de-interleaved code bits. The de-interleaver has a pipelined architecture such that sets of code bits are written into the memory at the same rate that sets of code bits are received onto the de-interleaver.10-01-2009
20090245430EFFICIENT PARALLEL SUB-PACKET DECODING USING MULTIPLE DECODERS - A configurable decoder within a receiver (for example, within a wireless communication device) includes numerous decoders. In one mode, the multiple decoders are used to decode different sub-packets of a packet. When one decoder completes decoding the last sub-packet assigned to it of the packet, then that decoder generates a packet done indication. A control circuit receives the packet done indications, and when all the decoders have generated packet done indications then the control circuit initiates an action. In one example, the action is the interrupting of a processor. The processor responds by reading status information from the control circuit, thereby resetting the interrupt. End-of-packet markers are usable to generate packet done indications and to generate EOP interrupts. Similarly, end-of-group markers are usable to generate group done indications and to generate EOG interrupts. The decoder block is configurable to process sub-packets of a packet using either one or multiple decoders.10-01-2009
20110105070Direct conversion receiver architecture - A direct downconversion receiver architecture having a DC loop to remove DC offset from the signal components, a digital variable gain amplifier (DVGA) to provide a range of gains, an automatic gain control (AGC) loop to provide gain control for the DVGA and RF/analog circuitry, and a serial bus interface (SBI) unit to provide controls for the RF/analog circuitry via a serial bus. The DVGA may be advantageously designed and located as described herein. The operating mode of the VGA loop may be selected based on the operating mode of the DC loop, since these two loops interact with one another. The duration of time the DC loop is operated in an acquisition mode may be selected to be inversely proportional to the DC loop bandwidth in the acquisition mode. The controls for some or all of the RF/analog circuitry may be provided via the serial bus.05-05-2011

Patent applications by Raghu Challa, San Diego, CA US

Raghu Narayan Challa, San Diego, CA US

Patent application numberDescriptionPublished
20110150152SYSTEMS AND METHODS PROVIDING FREQUENCY-DOMAIN AUTOMATIC GAIN CONTROL (AGC) - A method for Automatic Gain Control (AGC) in a receiver is performed by a circuit having an inner loop and an outer loop. The method includes performing an outer loop energy detection, mitigating interference using the outer loop energy detection, and performing a frequency domain energy measurement in the inner loop. The method also includes adjusting a digital gain component in the inner loop and an analog gain component in the outer loop in response to the frequency domain energy measurement.06-23-2011