Patents by Inventor Pei-Jun Shih
Pei-Jun Shih 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).
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Patent number: 8611475Abstract: A channel estimation method for use with a received signal by a receiver is disclosed. The received signal comprises multiple data bursts which are transmitted to the receiver via multiple path channels, with each of the data bursts having a plurality of preamble symbols which are decoded. The channel estimation method includes the following steps: firstly, at least one correlation pattern is generated according to the decoded preamble symbols. Then, a cross correlation of the correlation pattern with the received signal is performed to yield at least one correlation result of channel impulse response (CIR). Wherein, the symbol boundary of the received signal is decided according to the correlation result.Type: GrantFiled: June 13, 2011Date of Patent: December 17, 2013Assignee: Himax Media Solutions, Inc.Inventors: Pei-Jun Shih, Ching-Sheng Ni, Shin-Shiuan Cheng
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Patent number: 8451386Abstract: The invention discloses a digital IF demodulator for processing a digital IF signal converted from a radio frequency (RF) signal, including an NCO, a down conversion circuit, a PIF carrier recovery circuit and a video baseband demodulator. The NCO outputs a sine value and a cosine value. The down conversion circuit outputs a first zero IF signal including a first real part signal and a first imaginary part signal, according to the digital IF signal, the sine value and the cosine value. The PIF carrier recovery circuit outputs a loop error signal for the NCO and a second zero IF signal, according to the first zero IF signal and a video synchronization signal. The video baseband demodulator generates a composite video signal according to the second zero IF signal.Type: GrantFiled: June 8, 2009Date of Patent: May 28, 2013Assignee: Himax Media Solutions, Inc.Inventors: Tien-Ju Tsai, Pei-Jun Shih
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Publication number: 20120230453Abstract: A channel estimation method for use with a received signal by a receiver is disclosed. The received signal comprises multiple data bursts which are transmitted to the receiver via multiple path channels, with each of the data bursts having a plurality of preamble symbols which are decoded. The channel estimation method includes the following steps: firstly, at least one correlation pattern is generated according to the decoded preamble symbols. Then, a cross correlation of the correlation pattern with the received signal is performed to yield at least one correlation result of channel impulse response (CIR). Wherein, the symbol boundary of the received signal is decided according to the correlation result.Type: ApplicationFiled: June 13, 2011Publication date: September 13, 2012Applicant: HIMAX MEDIA SOLUTIONS, INC.Inventors: PEI-JUN SHIH, CHING-SHENG NI, SHIN-SHIUAN CHENG
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Patent number: 8139687Abstract: A digital demodulator adapted in a receiver and a digital demodulation method are provided. The digital demodulator includes: a phase splitter, a complex multiplier, an AFC, a limiter, a phase detector, a re-tracker, a post-multiplier and an oscillator. The phase splitter generates a complex signal from the input signal. The complex multiplier multiplies the complex signal by both first and second phase signals to generate first and second base band signals. The AFC generates a first output signal. The limiter generates a trend signal and the re-tracker generates a tuning signal from the first output signal. The phase detector multiplies the trend and second base signal and adjusts the multiplied signal based on the tuning signal. The oscillator generates the first and second phase signals according to the output of the phase detector. The post-multiplier multiplies the trend signal by the first and second base band signals for output.Type: GrantFiled: November 5, 2008Date of Patent: March 20, 2012Assignee: Himax Media Solutions, Inc.Inventors: Pei-Jun Shih, Tien-Ju Tsai, Jeng-Shiann Jiang
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Patent number: 8107014Abstract: A digital receiver includes an analog front-end circuit, an automatic-gain controller, a compensation circuit, and a demodulator. The analog front-end circuit receives an input signal, adjusts an average amplitude of the input signal, and converts the adjusted input signal to generate a digital signal according to a control signal. The automatic-gain controller is coupled to the analog front-end circuit for generating the control signal feedback to the analog front-end circuit according to the digital signal. The compensation circuit is coupled to the analog front-end circuit for detecting an average amplitude of the digital signal to generate a detecting result and for determining whether to compensate the average amplitude of the digital signal to generate a compensated digital signal according to the detecting result. The demodulator is coupled to the compensation circuit for demodulating the compensated digital signal to generate an output signal.Type: GrantFiled: March 9, 2009Date of Patent: January 31, 2012Assignee: Himax Media Solutions, Inc.Inventors: Jeng-Shiann Jiang, Pei-Jun Shih, Kuan-Hung Chen
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Patent number: 8102948Abstract: A carrier recovery apparatus includes a pilot strength detector, a first lock loop, a second lock loop, and a controller. The pilot strength detector determines whether a pilot strength of an input signal is greater than a threshold value to generate a control signal. The first lock loop performs a first carrier recovery on the input signal. The second lock loop performs a second carrier recovery on the input signal. The controller selectively allows the first lock loop to perform the first carrier recovery on the input signal or the second lock loop to perform the second carrier recovery on the input signal according to the control signal. The first lock loop is a pilot-based FPLL and the second locked loop is a pilot-less PLL.Type: GrantFiled: February 25, 2009Date of Patent: January 24, 2012Assignee: Himax Media Solutions, Inc.Inventors: Guo-Hau Gau, Pei-Jun Shih, Shin-Shiuan Cheng
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Patent number: 8045649Abstract: The invention provides carrier recovery systems and carrier recovery methods. The carrier recovery system comprises a compensation signal generator, a compensation device and a mode selector. The compensation signal generator generates a compensation signal based on a coherent demodulated signal. In a first mode, the compensate device is couple behind an equalizer; the coherent demodulated signal is generated by the compensation device which compensates the output of the equalizer with the compensation signal. In a second mode, the compensate device is coupled prior to the equalizer, compensating the output of a synchronizer with the compensation signal to generate the input of the equalizer. In the second mode, the compensation signal generator receives the output of the equalizer as the coherent demodulated signal. The mode selector switches the carrier recover system from the first mode to the second mode when an estimated frequency offset satisfies a first criterion.Type: GrantFiled: February 25, 2008Date of Patent: October 25, 2011Assignee: Himax Technologies LimitedInventors: Pei-Jun Shih, Jeng-Shiann Jiang
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Publication number: 20100309385Abstract: The invention discloses a digital IF demodulator for processing a digital IF signal converted from a radio frequency (RF) signal, including an NCO, a down conversion circuit, a PIF carrier recovery circuit and a video baseband demodulator. The NCO outputs a sine value and a cosine value. The down conversion circuit outputs a first zero IF signal including a first real part signal and a first imaginary part signal, according to the digital IF signal, the sine value and the cosine value. The PIF carrier recovery circuit outputs a loop error signal for the NCO and a second zero IF signal, according to the first zero IF signal and a video synchronization signal. The video baseband demodulator generates a composite video signal according to the second zero IF signal.Type: ApplicationFiled: June 8, 2009Publication date: December 9, 2010Applicant: HIMAX MEDIA SOLUTIONS, INC.Inventors: Tien-Ju Tsai, Pei-Jun Shih
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Publication number: 20100225822Abstract: A digital receiver includes an analog front-end circuit, an automatic-gain controller, a compensation circuit, and a demodulator. The analog front-end circuit receives an input signal, adjusts an average amplitude of the input signal, and converts the adjusted input signal to generate a digital signal according to a control signal. The automatic-gain controller is coupled to the analog front-end circuit for generating the control signal feedback to the analog front-end circuit according to the digital signal. The compensation circuit is coupled to the analog front-end circuit for detecting an average amplitude of the digital signal to generate a detecting result and for determining whether to compensate the average amplitude of the digital signal to generate a compensated digital signal according to the detecting result. The demodulator is coupled to the compensation circuit for demodulating the compensated digital signal to generate an output signal.Type: ApplicationFiled: March 9, 2009Publication date: September 9, 2010Inventors: Jeng-Shiann Jiang, Pei-Jun Shih, Kuan-Hung Chen
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Publication number: 20100215126Abstract: A carrier recovery apparatus includes a pilot strength detector, a first lock loop, a second lock loop, and a controller. The pilot strength detector determines whether a pilot strength of an input signal is greater than a threshold value to generate a control signal. The first lock loop performs a first carrier recovery on the input signal. The second lock loop performs a second carrier recovery on the input signal. The controller selectively allows the first lock loop to perform the first carrier recovery on the input signal or the second lock loop to perform the second carrier recovery on the input signal according to the control signal. The first lock loop is a pilot-based FPLL and the second locked loop is a pilot-less PLL.Type: ApplicationFiled: February 25, 2009Publication date: August 26, 2010Inventors: Guo-Hau Gau, Pei-Jun Shih, Shin-Shiuan Cheng
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Publication number: 20100111240Abstract: A digital demodulator adapted in a receiver and a digital demodulation method are provided. The digital demodulator comprises: a phase splitter, a complex multiplier, an AFC, a limiter, a phase detector, a re-tracker, a post-multiplier and an oscillator. The phase splitter generates a complex signal from the input signal. The complex multiplier multiplies the complex signal by both first and second phase signals to generate first and second base band signals. The AFC generates a first output signal. The limiter generates a trend signal and the re-tracker generates a tuning signal from the first output signal. The phase detector multiplies the trend and second base signal and adjusts the multiplied signal based on the tuning signal. The oscillator generates the first and second phase signals according to the output of the phase detector. The post-multiplier multiplies the trend signal by the first and second base band signals for output.Type: ApplicationFiled: November 5, 2008Publication date: May 6, 2010Applicant: Himax Media Solutions, Inc.Inventors: Pei-Jun Shih, Tien-Ju Tsai, Jeng-Shiann Jiang
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Publication number: 20090213921Abstract: The invention provides carrier recovery systems and carrier recovery methods. The carrier recovery system comprises a compensation signal generator, a compensation device and a mode selector. The compensation signal generator generates a compensation signal based on a coherent demodulated signal. In a first mode, the compensate device is couple behind an equalizer; the coherent demodulated signal is generated by the compensation device which compensates the output of the equalizer with the compensation signal. In a second mode, the compensate device is coupled prior to the equalizer, compensating the output of a synchronizer with the compensation signal to generate the input of the equalizer. In the second mode, the compensation signal generator receives the output of the equalizer as the coherent demodulated signal. The mode selector switches the carrier recover system from the first mode to the second mode when an estimated frequency offset satisfies a first criterion.Type: ApplicationFiled: February 25, 2008Publication date: August 27, 2009Applicant: HIMAX TECHNOLOGIES LIMITEDInventors: Pei-Jun Shih, Jeng-Shiann Jiang