Patents Assigned to Ralink Technology Corp.
  • Patent number: 8300738
    Abstract: A power-saving method for Viterbi decoder and bit processing circuit of wireless receiver is provided. In response to various computational load of bit processing circuit and/or Viterbi decoder of a wireless receiver, the method is used for adjusting duty cycle of the bit processing circuit and/or the Viterbi decoder so as to save power in addition, in response to various data rates of the wireless receiver, the Viterbi decoder and the bit processing circuit are provided with power based on various duty cycles of related time pulse signals, thereby preventing the Viterbi decoder and/or the bit processing circuit from consuming power while being idle (during time segments of idle operation), so as to reduce power consumption.
    Type: Grant
    Filed: December 4, 2008
    Date of Patent: October 30, 2012
    Assignee: Ralink Technology Corp.
    Inventor: Shih-Yi Yeh
  • Patent number: 8279949
    Abstract: A method for estimating a length of a channel in a wired communication system includes receiving a plurality of signals transmitted continuously via the channel, determining relation between a signal and at least one signal in the of the plurality of signals, to generate a decision result, and determining the length of the channel according to the decision result.
    Type: Grant
    Filed: June 23, 2010
    Date of Patent: October 2, 2012
    Assignee: Ralink Technology Corp.
    Inventors: Wen-Sheng Hou, Li-Hua Weng, Guan-Henry Lin
  • Patent number: 8269556
    Abstract: A method for cancelling magnetic coupling in an amplifier is disclosed. The amplifier includes a first path and a second path for outputting a first signal and a second signal, respectively, and the first signal and the second signal have a specific phase difference. The method includes forming a first LC tank and a second LC tank in the first path, and forming a third LC tank and a forth LC tank in the second path.
    Type: Grant
    Filed: January 12, 2011
    Date of Patent: September 18, 2012
    Assignee: Ralink Technology Corp.
    Inventor: Pi-An Wu
  • Patent number: 8269551
    Abstract: A complex filter for processing an in-phase signal and a quadrature-phase signal includes a first low-pass filter, a second low-pass filter, a connection unit between the first low-pass filter and the second low-pass filter, a first compensation resistor and a second compensation resistor. The first compensation resistor and the second compensation resistor are interlacedly coupled to input resistors of the first low-pass filter and the second low-pass filter.
    Type: Grant
    Filed: September 30, 2010
    Date of Patent: September 18, 2012
    Assignee: Ralink Technology Corp.
    Inventor: Che-Hung Liao
  • Patent number: 8254479
    Abstract: A method and related system of transmission channel detection condition in a wireless communication system are disclosed. The method includes receiving a symbol, performing a channel estimation operation to generate a channel estimation result according to the symbol, performing a cross correlation operation on the channel estimation result and an initial channel estimation result to generate an operation result, and determining whether the condition of the transmission channel have changed or not.
    Type: Grant
    Filed: July 12, 2009
    Date of Patent: August 28, 2012
    Assignee: Ralink Technology, Corp.
    Inventors: Yung-Szu Tu, Jiunn-Tsair Chen, Yen-Chin Liao, Cheng-Hsuan Wu
  • Patent number: 8239672
    Abstract: A method for a access point device having first network identity information to automatically establish a security link with a peer access point device in a wireless communication system includes searching and receiving a beacon corresponding to the peer access point device by radio frequency scan, obtaining second network identity information corresponding to the peer access point device from the beacon, determining a primary-secondary relationship for the access point device and the peer access point device according to the first and second network identity information, generating or receiving security data according to the primary-secondary relationship, and then establishing the security link with the peer access point device according to the security data.
    Type: Grant
    Filed: May 19, 2009
    Date of Patent: August 7, 2012
    Assignee: Ralink Technology, Corp.
    Inventors: Chih-Chang Chen, Sung-Chien Tang
  • Patent number: 8228074
    Abstract: A method for estimating cable length includes steps of generating a detection signal to a cable, wherein the detection signal includes a first pulse and a second pulse with opposite voltages in sequence; receiving a refection signal of the detection signal from the cable; and determining length of the cable according to a superposed waveform of the detection signal and the refection signal.
    Type: Grant
    Filed: July 12, 2009
    Date of Patent: July 24, 2012
    Assignee: Ralink Technology, Corp.
    Inventors: Guan-Henry Lin, Tsung-Hsuan Wu, Wen-Sheng Hou
  • Patent number: 8222925
    Abstract: A multimode line driver circuit is provided. The multimode line driver circuit has a first driver circuit for receiving a first differential input signal and transmitting a first differential output signal, and a second driver circuit for receiving a second driver circuit for receiving a second differential input signal and transmitting a second differential output signal. The multimode line driver circuit also has a first switch coupling the first driver circuit to a first power supply and a second switch coupling the second driver circuit to a second power supply. The multimode line driver circuit also has a transformer coupled to the output interface for transforming the first differential output and the second differential output and a mode controller configured to close the first switch in the first mode and to close the second switch in the second mode.
    Type: Grant
    Filed: September 29, 2009
    Date of Patent: July 17, 2012
    Assignee: Ralink Technology Corp.
    Inventors: Hsin-Hsien Li, Chin-Chun Lin, Tsung-Hsien Hsieh, Zi-Long Huang
  • Patent number: 8189702
    Abstract: The present invention discloses a scattering-parameter estimation method for a transceiver of a half-duplex multicarrier communication system. The scattering-parameter estimation method includes steps of converting a first frequency-domain transmit signal to generate at least one symbol period of the first time-domain transmit signal; transmitting the first time-domain signal in a first specific time period; receiving and storing at least one symbol period of the first echoed signal of the first time-domain transmit signal in the first specific time period; converting at least one symbol period of the first echoed signal into a first frequency-domain echoed signal after a first transmission period; and estimating the S11 parameters corresponding to carriers respectively according to the first transmit signal and the first echoed signal.
    Type: Grant
    Filed: May 24, 2011
    Date of Patent: May 29, 2012
    Assignee: Ralink Technology Corp.
    Inventor: Ching-Kae Tzou
  • Patent number: 8145154
    Abstract: An approximation method for SNR soft information for a transmitter of a communications system includes obtaining a conditional probability density function (PDF) corresponding to a response message of a transmitted packet, obtaining a PDF of a probability distribution model, and a mean and a variance of the PDF, by approximating the conditional PDF corresponding to the response message with the probability distribution model, and calculating a second mean and a second variance of a second PDF approximated to a conditional PDF of SNR corresponding to the transmitted packet according to the mean and the variance of the PDF, and a first mean and a first variance of a first PDF approximated to a conditional PDF of SNR corresponding to another transmitted packet immediately preceding the transmitted packet.
    Type: Grant
    Filed: June 7, 2009
    Date of Patent: March 27, 2012
    Assignee: Ralink Technology, Corp.
    Inventors: Yung-Szu Tu, Jiunn-Tsair Chen, Chun-Hsien Wen, Cheng-Hsuan Wu, Chien-Cheng Lin
  • Patent number: 8095807
    Abstract: A method and a system for power saving and state retention in an electronic device are provided. The method for power saving and state retention in an electronic device includes recording a state variation of electronic components of a plurality of groups in a second circuit of the electronic device in a variation table stored in memory of a first circuit or the second circuit of the electronic device; before stopping providing power to the second circuit, selecting some groups from the plurality of groups according to the variation table and making a backup of states of electronic components of the selected groups; and after restoring power to the second circuit, restoring the states of electronic components of the selected groups according to states in the backup.
    Type: Grant
    Filed: December 19, 2008
    Date of Patent: January 10, 2012
    Assignee: Ralink Technology Corp.
    Inventor: Kuo-Cheng Lu
  • Patent number: 8068796
    Abstract: A power divider includes a substrate, a signal reception terminal formed in a first layer of the substrate for receiving signals, a first output terminal formed in the first layer for outputting radio-frequency (RF) signals, a matching terminal formed in a third layer of the substrate, a second output terminal formed in the third layer for outputting RF signals, a grounding plate formed in a second layer of the substrate, surrounding a hole and forming a circular shape, a first block transmission line formed at a position corresponding to the hole in the first layer and coupled to the signal reception terminal and the first output terminal, and a second block transmission line formed at a position corresponding to the hole in the third layer, coupled to the matching terminal and the second output terminal, and having a shape identical to a shape of the first block transmission line.
    Type: Grant
    Filed: December 10, 2009
    Date of Patent: November 29, 2011
    Assignee: Ralink Technology Corp.
    Inventors: Min-Chung Wu, Shao-Chin Lo
  • Patent number: 8064845
    Abstract: A RF transceiver includes an antenna, a receiver, a baseband circuit, a transmitter, and a T/R switch circuit. The T/R switch circuit is used for coupling the antenna and the receiver or coupling the antenna and the transmitter. The T/R switch circuit is coupled to the baseband circuit so as to receive biases provided from the baseband circuit. The T/R switch circuit includes four transistors and a power detector. The power detector detects the power of the output signal of the T/R switch circuit, so that the baseband circuit can adjust biases provided to the T/R switch circuit according to the power of the output signal.
    Type: Grant
    Filed: November 30, 2008
    Date of Patent: November 22, 2011
    Assignee: Ralink Technology, Corp.
    Inventors: Chun-Hsueh Chu, Jiunn-Tsair Chen
  • Patent number: 8050633
    Abstract: A wireless communication system is disclosed. The present invention mainly includes a transceiver, a first filter unit, a second filter unit, and a first amplifying unit, wherein the first filter unit is a harmonic oscillation circuit having an inductive component and a capacitive component serially coupled to each other, and the harmonic oscillation circuit as well as the circuit of the second filter unit efficiently filter out a local oscillation frequency signal and intermediate frequency signal traveling along with a radio frequency signal, thereby preventing neighboring communication systems from electro-magnetic interference due to radiation of the local oscillation frequency signal and intermediate frequency signal into air via an antenna after being amplified by the first amplifying unit.
    Type: Grant
    Filed: February 24, 2009
    Date of Patent: November 1, 2011
    Assignee: Ralink Technology Corp.
    Inventor: Yude Liao
  • Patent number: 8031675
    Abstract: A system for detecting wireless base stations and a method thereof are provided. The system includes a detection module, a count module, a storage module, and a switch module. The method includes sending a detection request to a channel, determining whether a wireless base station corresponding to the channel physically exits, and whether the channel is detected, based on a detection response returned by the channel; returning a detection response; calculating the sum of the detection request and the detection response so as to create a count result to be stored in the storage module; and switching directly from the wireless base station currently in use and the corresponding channel to the next undetected channel and a corresponding wireless base station, based on the count result.
    Type: Grant
    Filed: February 24, 2009
    Date of Patent: October 4, 2011
    Assignee: Ralink Technology Corp.
    Inventor: Hsin-Yi Lee
  • Patent number: 8022758
    Abstract: A circuit comprises an amplifier circuit and a trimming circuit. The amplifier circuit includes an operational amplifier. The operational amplifier has a first input configured to receive input signals, and the operational amplifier also has a second input and an amplifier output. One of the first input or the second input is a negative input. The trimming circuit is coupled to the amplifier output. The trimming circuit includes a termination resistor coupled in parallel with at least one trimming resistor. The termination resistor is coupled to a first switch in series, and the trimming resistor is coupled to a second switch in series. The amplifier output is connected back to the negative input through the first switch.
    Type: Grant
    Filed: January 6, 2010
    Date of Patent: September 20, 2011
    Assignee: Ralink Technology Corp.
    Inventors: Hsin-Hsien Li, Chin-Chun Lin, Tsung-Hsien Hsieh, Zi-Long Huang
  • Patent number: 7999612
    Abstract: An operational amplifier includes an input stage for generating a first differential output signal pair according to a first differential input signal pair, an output stage for generating a second differential output signal pair according to at least a second differential input signal pair, and a high-pass filtering circuit coupled between the input stage and the output stage for performing high-pass filtering on the first differential output signal pair, for generating the at least a second differential input signal pair.
    Type: Grant
    Filed: January 27, 2010
    Date of Patent: August 16, 2011
    Assignee: Ralink Technology Corp.
    Inventor: Yi-Bin Hsieh
  • Patent number: 7990176
    Abstract: A line driver for a communications system requiring multiple power sources for different modes of operation comprises a current source and a voltage source coupled in parallel with the current source. The current source has a first terminal and a second terminal. The line driver further comprises a first source resistor coupled to the first terminal of the current source and a second source resistor coupled to the second terminal of the current source. The current source provides a driving current and the voltage source provides a driving voltage at the same time during operations of the communications system.
    Type: Grant
    Filed: September 23, 2009
    Date of Patent: August 2, 2011
    Assignee: Ralink Technology Corp.
    Inventors: Hsin-Hsien Li, Chin-Chun Lin, Tsung-Hsien Hsieh, Zi-Long Huang
  • Patent number: 7948427
    Abstract: A method for detecting radar signal comprises the steps of: sampling a received signal so as to obtain a plurality of sampling values; taking an absolute value of the sampling values so as to obtain at least two parameters; and determining whether the received signal includes radar signals in accordance with the at least two parameters.
    Type: Grant
    Filed: September 29, 2008
    Date of Patent: May 24, 2011
    Assignee: Ralink Technology Corp.
    Inventors: Chun Hsien Wen, Jiunn Tsair Chen
  • Patent number: 7903017
    Abstract: A comparator for a pipelined ADC includes a sampling circuit coupled to a plurality of differential input voltages and a plurality of differential reference voltages, for sampling the plurality of differential input voltages according to a first clock signal and sampling the plurality of differential reference voltages according to a second clock signal, a preamplifier coupled to the sampling circuit comprising a positive input terminal, a negative input terminal, a positive output terminal, and a negative output terminal, for amplifying a voltage across the positive input terminal and the negative input terminal for generating a plurality of differential output voltages, and a latch circuit coupled to the preamplifier for latching the plurality of differential output voltages.
    Type: Grant
    Filed: August 28, 2009
    Date of Patent: March 8, 2011
    Assignee: Ralink Technology Corp.
    Inventors: Yi-Bin Hsieh, Heng-Chih Lin