Mediatek Corporation

Realtek Semiconductor Inc.

Benq Corporation

Beno Corporation

Bao-Chi Peng

Cheng-Yi Huang

Wei-Ting Wang

Qiang Zhou

Chun-Chia Chen

Gilles Charbit

I-Kang Fu

Chih-Ming Hung

Abdelkader Medles

Chih-Yuan Lin

Tzu-Chin Lin

Charles Chien

Jui-Lin Hsu

Chao-Ching Hung

Balachander Narasimhan

Cheng-Chou Zhan

Yun-Shiang Shu

Hua Wang

Shao-Chou Hung

Provided is an apparatus for transmitting a circularly polarized signal by linearly polarized antennas. A horizontally polarized antenna and a vertically polarized antenna of the apparatus receives a first circularly polarized signal transmitted based on a transmitted baseband signal vector. Based on the first circularly polarized signal, a radio frequency (RF) module of the apparatus generates a received baseband signal vector including a product of the transmitted baseband signal vector and a receiving polarization vector of the transmitted baseband signal vector. Processing circuitry of the apparatus estimates the receiving polarization vector based on the received baseband signal vector and calibrates power amplifiers (PAs) and local oscillator (LO) signals of frequency converters in the RF module based on the estimated receiving polarization vector. The horizontally and vertically polarized antennas transmit a second circularly polarized signal based on the calibrated PAs and the calibrated LO signals of the frequency converters.

Transmitting or receiving circularly polarized signals by linearly polarized antennas

Aspects of the disclosure provide an apparatus for receiving a circularly polarized signal by linearly polarized antennas. A horizontally polarized antenna and a vertically polarized antenna of the apparatus receive a circularly polarized signal that is transmitted based on a transmitted baseband signal vector. A radio frequency (RF) module of the apparatus generates a first baseband signal vector based on the received circularly polarized signal. The first baseband signal vector includes a product of the transmitted baseband signal vector and a receiving polarization vector of the transmitted baseband signal vector. Processing circuitry of the apparatus estimates the receiving polarization vector of the transmitted baseband signal vector based on the first baseband signal vector. The processing circuitry derives a second baseband signal vector based on the estimated receiving polarization vector and the first baseband signal vector.

A system includes a local oscillator (LO) signal generation circuit, a receiver (RX) circuit, and a calibration circuit. The LO signal generation circuit generates an LO signal according to a reference clock, and includes an active oscillator that generates the reference clock. The active oscillator includes at least one active component. The RX circuit generates a processed RX signal by processing an RX input signal according to the LO signal. The calibration circuit checks a signal characteristic of the processed RX signal by detecting if a calibration tone exists within a receiver bandwidth, set a frequency calibration control output in response to the calibration tone being not found in the receiver bandwidth, and output the frequency calibration control output to the LO signal generation circuit. The LO signal generation circuit adjusts an LO frequency of the LO signal in response to the frequency calibration control output.

Apparatus and method for applying frequency calibration to local oscillator signal derived from reference clock output of active oscillator

A wireless system includes a local oscillator (LO) signal generation circuit, a receiver (RX) circuit, and a calibration circuit. The LO signal generation circuit generates an LO signal according to a reference clock. The LO signal generation circuit includes an active oscillator. The active oscillator generates the reference clock, wherein the active oscillator includes at least one active component, and does not include an electromechanical resonator. The RX circuit generates a down-converted RX signal by performing down-conversion upon an RX input signal according to the LO signal. The calibration circuit generates a frequency calibration control output according to a signal characteristic of the down-converted RX signal, and outputs the frequency calibration control output to the LO signal generation circuit. The LO signal generation circuit adjusts an LO frequency of the LO signal in response to the frequency calibration control output.

Apparatus and method for applying frequency calibration to local oscillator signal derived from reference clock output of active oscillator that has no electromechanical resonator

An electronic device has a transmit circuit and a processing circuit. The processing circuit outputs a first portion of compressive sensing (CS) samples corresponding to a signal segment to another electronic device via the transmit circuit, and selectively outputs a second portion of the CS samples corresponding to the signal segment to another electronic device via the transmit circuit according to a response of another electronic device. In this way, a balance between the compression ratio and the reconstruction quality/speed can be achieved. Moreover, the signal reconstruction performed at the processing circuit may employ a multi-resolution/multi-scale reconstruction scheme to achieve a balance between the dictionary size and the reconstruction quality/speed, and/or may employ a multi-stage reconstruction scheme to achieve a balance between the reconstruction algorithm control setting and the reconstruction quality/speed. In addition, dictionary weighting, online dictionary update, and/or point constraints may be used to improve the reconstruction quality.

Electronic device with flexible processing of compressive sensing samples

An electronic device for a wireless communication system is described. The electronic device comprises: a receiver configured to receive a modulated signal on a communication channel; and a processor, coupled to the receiver and configured to: process the received modulated signal; identify a communication channel characteristic based on the processed received modulated signal; select an equalizer having a first set of equalization coefficients based on the identified communication channel characteristic, wherein the first set of equalization coefficients is selected from a plurality of equalization coefficients, each of the plurality of equalization coefficients being associated with different communication channel characteristics; equalize the processed received modulated signal on the communication channel using the selected equalizer; and detect the equalized received modulated signal.

Electronic device with equalization, integrated circuit and methods therefor

A method and apparatus for rejecting an interference signal from an input frequency spectrum. The method includes the steps of receiving the input signal; frequency-shifting the received input signal by a first frequency-shifting amount; and filtering the frequency-shifted input signal to filter out the interference component from the input signal.

Method and apparatus for detecting and rejecting NTSC Interference in ATSC system

A synchronization signal detector includes: a first circuit configured to delay the data signal by a period of at least one data segment of the data signal to generate a delayed signal; a second circuit configured to produce a plurality of similarity signals according to the data signal and the delayed signal, each of the similarity signals representing the similarity between the data signal and the delayed signal, and a third circuit configured to determine the synchronization signal of the data signal according to the similarity signals. The present invention further provides a method corresponding to the signal detector.

Apparatus and method for detecting synchronization signal of data signal utilizing synchronization symbols

An interference detecting circuit for use in an ATSC system and for detecting interference of an ATSC signal includes: a buffering module for delaying to output a first PNsynchronization format data when receiving the first PNsynchronization format data; a correlation arithmetic circuit coupled to the buffering module for receiving the ATSC signal and performing a correlation operation on a second PNsynchronization format data and the delayed first PNsynchronization format data to output a detection signal when receiving the second PNsynchronization format data; and a determining circuit for determining whether performing interference rejection on the ATSC signal or not according to the result of the above-mentioned correlation operation.

Interference detecting circuit utilizing synchronization symbols and method thereof

A carrier recovery system includes an in-phase mixer for mixing an incoming signal with an in-phase reference signal to produce an in-phase baseband signal; a quadrature-phase mixer for mixing the incoming signal with a quadrature-phase reference signal to produce a quadrature-phase baseband signal; a DC detector for measuring a DC offset of the quadrature-phase baseband signal; and a frequency synthesizer for generating the in-phase reference signal and the quadrature-phase reference signal according to the DC offset measured by the DC detector. The quadrature-phase reference signal is the in-phase reference signal phase-delayed by ninety degrees. The DC offset of the quadrature-phase baseband signal is caused by a pilot tone of the VSB signal for a selected carrier in an Advanced Television Systems Committee (ATSC) digital television (DTV) receiver. By minimizing the DC offset, the carrier recover system locks the quadrature-phase reference signal and the in-phase reference signal to the selected channel.

Carrier recovery system and method thereof

A system for reassigning a plurality of tracking units of a wireless receiver, for receiving a plurality of multipath signals in a predetermined time period to reconstruct correspondingly an original signal. The system includes a searcher, a tracker and an assigning management unit. In particular, a predetermined estimating process includes the following steps to generate the assigning value of a combination of matching pairs: subtracting the searching time position and the predetermined tracking time position of every matching pairing the combination and taking absolute values to obtain a plurality of corresponding subtraction values; inputting the plurality of subtraction values to a predetermined estimating function to obtain a plurality of corresponding estimation values; and summing up the plurality of estimation values and obtaining the assigning value of the combination of matching pairs.

Method of tracking finger assignment

A digital television receiver includes a tuner for down-converting an incoming signal to produce a down-converted signal according to a local oscillator signal corresponding to a selected channel. A filter is coupled to the tuner for filtering the down-converted signal to produce an intermediate frequency (IF) signal. A carrier recovery unit is coupled to the filter for locking to a carrier frequency of the IF signal, and a pre-shift unit is coupled to the tuner. By shifting the local oscillator signal in a first direction by a predetermined first frequency shift in a first phase of carrier recovery, and then by shifting the local oscillator signal in a second direction by a second frequency shift in a second phase of carrier recovery, the pre-shift unit ensures a pilot tone of a selected channel is not filtered from the down-converted signal by the filter.

Digital television receiver and method of recovering incoming digital television signal

A WCDMA receiver in which the dependencies of different functional modules are arranged to allow proper tailoring of the Channel Estimation (CE) module bandwidth. A PreCE provides rough estimation results of the channel complex gain. The rough estimation results are passed to the Automatic Frequency Control (AFC). The AFC outputs a signal transmitted to two mixers. The first mixer mixes the output of the PreCe with the output of the AFC and outputs the result to a Velocity estimator (VE) and a PostCE to generate the compensating signals. The output of the VE is also transmitted to the PostCE. The output of the PostCE is sent to a Maximum Ratio Combining module, whose output is mixed by the second mixer with the output of the AFC to generate a final signal.

Signal demodulation in a mobile receiver

A frequency offset detector for AFC under Rayleigh fading. The AFC includes a variable phase generator, an exponential term emultiplied on an incoming signal, a low-pass filter, a gain amplifier, a multiplier, and an offset detector. The offset detector includes a filter, an amplifier, a delay block, three adders, and two blocks that output the absolute value of an inputted signal. The filter is a Finite Impulse Response (FIR) filter that produces a Hilbert Transformation of the inputted complex gain. The Hilbert FIR filter, together with the complex gain and two of the adders, generate two complex signals: Xp and Xn respectively representing the positive and negative frequency components of the inputted complex gain. The detector output is equal to the difference between the magnitudes of Xp and Xn.

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Taipei, Taiwan

Bao-Chi Peng