Abstract: A channel estimator and a channel estimation method are provided. The channel estimator comprises a storage module, for storing a plurality of channel responses of first pilot signals over a plurality of continuous pilot sub-channels, and a plurality of channel responses of second pilot signals over a scatter pilot sub-channel; and a calculation module, for calculating a channel response at a time point without a pilot signal over the scatter pilot sub-channel according to the channel responses of the first pilot signals and the channel responses of the second pilot signals.

Abstract: A broadcast receiver includes a tuner circuit and a demodulator circuit. The tuner circuit tunes a radio frequency (RF) signal to output an intermediate frequency (IF) signal. The demodulator circuit demodulates the IF signal from the tuner circuit and outputs a command signal based on the quality of the IF signal, for changing a take over point (TOP) value, preset in the tuner circuit, at which one amplitude gain control (AGC) stopping and another taking over. A method for regulating a broadcast receiver is also disclosed herein.

Abstract: Disclosed is an automatic video gain control circuit, which includes an analog to digital converter, an envelope detector and an extreme value detector. The analog to digital converter converts an analog video signal to a digital video signal. The envelope detector detects a baseband amplitude signal according to the digital video signal. The extreme value detector generates an extreme value to control RF signal gain.

Abstract: A frequency offset estimating apparatus includes an nth power computing module and a spectrum analyzing module. By raising a received signal to nth power to generate an nth power signal and analyzing the spectrum of the nth power signal, the present invention is capable of quickly and accurately estimating a frequency offset of the received signal. As being unaffected by channel characteristics, the estimating frequency offset apparatus is suitable for all channel environments.

Abstract: The invention discloses a double-estimation channel estimator for calculating a plurality of accurate channel responses from a plurality of synchronization signals. The channel estimator includes a first channel estimator, a second channel estimator, a first equalizer, and a calculation module. The first channel estimator calculates first channel responses according to a plurality of pilot signals and the synchronization signals. The first equalizer calculates first equalization signals according to the first channel responses and the synchronization signals. The second channel estimator calculates second responses according to the first equalization signals and the synchronization signals. Then the calculation module calculates third channel responses according to the first channel responses and the second channel responses.

Abstract: A frequency adjusting method comprises steps of: generating a first adjusting signal according to a frequency of a first output signal; adjusting a frequency of an input signal by using the first adjusting signal to generate the first output signal, so as to adjust the frequency of the first output signal into a first range; generating a second adjusting signal according to a frequency of a second output signal; adjusting the frequency of the first output signal by using the second adjusting signal to generate the second output signal, so as to adjust the frequency of the second output signal into a second range; and adjusting the first adjusting signal and the second adjusting signal according to the second adjusting signal.

Abstract: A broadcast receiver includes a tuner circuit and a demodulator circuit. The tuner circuit tunes a radio frequency (RF) signal to output an intermediate frequency (IF) signal. The demodulator circuit demodulates the IF signal from the tuner circuit and outputs a command signal based on the quality of the IF signal, for changing a take over point (TOP) value, preset in the tuner circuit, at which one amplitude gain control (AGC) stopping and another taking over. A method for regulating a broadcast receiver is also disclosed herein.

Abstract: A phase detecting module capable of optimizing detection accuracy and noise robustness, and a detecting method, are included. The phase detecting module includes a phase detecting circuit, an energy estimating circuit and a selecting circuit. The phase detecting circuit detects a phase of an input signal to generate a phase detection value. The energy estimating circuit estimates energy of the input signal to generate an energy estimation value. The selecting circuit selectively outputs the phase detection value according to the energy estimation value.

Abstract: The invention discloses a double-estimation channel estimator for calculating a plurality of accurate channel responses from a plurality of synchronization signals, comprising a first channel estimator, for calculating a plurality of first channel responses at all time points over all sub-channels according to a plurality of pilot signals and the synchronization signals; a first equalizer, for calculating a plurality of first equalization signals at all the time points over all the sub-channels according to the first channel responses and the synchronization signals; a second channel estimator, for calculating a plurality of second responses at all the time points over all the sub-channels according to the first equalization signals and the synchronization signals; and a calculation module, for calculating a plurality of third channel responses at all the time points over all the sub-channels according to the first channel responses and the second channel responses.

Abstract: A channel estimator and a channel estimation method are provided. The channel estimator comprises a storage module, for storing a plurality of channel responses of first pilot signals over a plurality of continuous pilot sub-channels, and a plurality of channel responses of second pilot signals over a scatter pilot sub-channel; and a calculation module, for calculating a channel response at a time point without a pilot signal over the scatter pilot sub-channel according to the channel responses of the first pilot signals and the channel responses of the second pilot signals.

Abstract: A frequency offset estimating apparatus includes an nth power computing module and a spectrum analyzing module. By raising a received signal to nth power to generate an nth power signal and analyzing the spectrum of the nth power signal, the present invention is capable of quickly and accurately estimating a frequency offset of the received signal. As being unaffected by channel characteristics, the estimating frequency offset apparatus is suitable for all channel environments.

Abstract: A frequency adjusting method comprises steps of: generating a first adjusting signal according to a frequency of a first output signal; adjusting a frequency of an input signal by using the first adjusting signal to generate the first output signal, so as to adjust the frequency of the first output signal into a first range; generating a second adjusting signal according to a frequency of a second output signal; adjusting the frequency of the first output signal by using the second adjusting signal to generate the second output signal, so as to adjust the frequency of the second output signal into a second range; and adjusting the first adjusting signal and the second adjusting signal according to the second adjusting signal.

Abstract: A phase detecting module capable of optimizing detection accuracy and noise robustness, and a detecting method, are included. The phase detecting module includes a phase detecting circuit, an energy estimating circuit and a selecting circuit. The phase detecting circuit detects a phase of an input signal to generate a phase detection value. The energy estimating circuit estimates energy of the input signal to generate an energy estimation value. The selecting circuit selectively outputs the phase detection value according to the energy estimation value.

Abstract: A smart channel scan method and associated apparatus, for searching center frequencies and symbol rates of the video signal channels. The smart channel scan method performs spectrum analysis for the video signal to generate a power spectrum density signal and obtain a plurality of center frequencies and coarse bandwidth. Symbol rates are determined according to the power spectrum density signal and the coarse bandwidth.

Abstract: Disclosed is an automatic video gain control circuit, which includes an analog to digital converter, an envelope detector and an extreme value detector. The analog to digital converter converts an analog video signal to a digital video signal. The envelope detector detects a baseband amplitude signal according to the digital video signal. The extreme value detector generates an extreme value to control RF signal gain.

Abstract: A system and a method for deriving transmitted signals from multiple users for an OFDM-CDMA communication system are described herein. An optimum synchronizer for use in an OFDM-CDMA system is also provided. In one aspect, the system and method incorporate a programmable structure for different OFDM-CDMA systems (e.g., MC-CDMA, MC-DS-CDMA, and MT-CDMA) that can be efficiently implemented. The programmable structure is based on the linear minimum mean square error (LMMSE) or best linear unbiased estimator (BLUE) techniques. In addition, an efficient algorithm for reducing computations of fast Fourier transform (FFT) is presented.

Abstract: A system and a method for deriving transmitted signals from multiple users for an OFDM-CDMA communication system are described herein. An optimum synchronizer for use in an OFDM-CDMA system is also provided. In one aspect, the system and method incorporate a programmable structure for different OFDM-CDMA systems (e.g., MC-CDMA, MC-DS-CDMA, and MT-CDMA) that can be efficiently implemented. The programmable structure is based on the linear minimum mean square error (LMMSE) or best linear unbiased estimator (BLUE) techniques. In addition, an efficient algorithm for reducing computations of fast Fourier transform (FFT) is presented.