Abstract: There are provided a phase-compensation decision feedback channel equalizer. The phase-compensation decision feedback channel equalizer equalizes phases of signals outputted from a feedforward filter and a feedback filter regardless of a phase distorted by a carrier wave and a ghost, thereby satisfying the same ghost removal performance.

Abstract: Timing recovery device for recovering a symbol clock from a received broadcasting signal, wherein a sign is used as a timing error, which is extracted from a result of multiplication of a difference of two symbol samples and an intermediate sample thereof, thereby very great average gain with respect to the timing error, that shortens a time period required for capturing the timing error. Particularly, since the very great average gain is obtainable even in a case a 0 dB presents, the timing offset can be captured at a short time period.

Abstract: A carrier restoration apparatus for acquiring a frequency offset and tracking a phase jitter from a pass-band digital signal having the frequency offset and the phase jitter is disclosed. In the apparatus, a frequency acquisition PLL section for acquiring the frequency offset and a phase tracking PLL section for tracking the residual phase jitter are separately constructed, and the apparatus operates in two modes for first acquiring the frequency offset and then tracking the residual phase jitter. Thus, a rapid acquisition/tracking is performed so as to minimize the frequency offset and phase jitter of several hundred KHz produced from a tuner or an RF oscillator, and a high-reliability acquisition/tracking can be performed even under the low SNR and serious channel ISI (i.e., ghost).

Abstract: A digital passband matched filter is automatically adapted to a carrier wave ? in accordance with a frequency offset of the carrier wave, to obtain a passband digital signal having no frequency distortion due to the frequency offset. Thus, a receiver in which drawbacks such as decrease of SNR and increase of circuit complexity caused by the fixed baseband/passband matched filter is obtained. Since a cosine wave generating section operates in a carrier wave frequency restoring mode and a carrier wave frequency adaptive mode, respectively, a single cosine wave ROM table can be used regardless of the respective operating modes, thereby reducing circuit complexity. Since the digital passband matched filter acts to renew the filter coefficients adapted to the carrier wave adaptive mode only, power consumption required to operate the filter can be minimized.

Abstract: Disclosed is a quadrature amplitude modulation (QAM) receiver and a carrier recovery method which receive a signal modulated by the QAM method and recover the frequency offset and phase jitter of the carrier particularly using a weighted phase error inversely proportionate to the magnitude of the deciding signal character, as a result of which the phase jitter of the demodulated signal characters is constant in size irrespective of the magnitude of the deciding signal character. Consequently, acquisition/tracking can be rapidly achieved to minimize the frequency offset of several hundreds of KHz and the phase jitter generated from a tuner or an RF oscillator.

Abstract: A lock detecting apparatus for a multimedia digital broadcasting receiver is disclosed. The present invention is a general purpose lock detecting apparatus applicable to a channel equalizer as well as a carrier recovery unit. Also, the present lock detecting apparatus uses two lock threshold values throughout a pull-in and lock-in, to improve the reliability of the lock detector for a false lock.

Abstract: Timing recovery device for recovering a symbol clock from a received broadcasting signal, wherein a sign is used as a timing error, which is extracted from a result of multiplication of a difference of two symbol samples and an intermediate sample thereof, thereby very great average gain with respect to the timing error, that shortens a time period required for capturing the timing error. Particularly, since the very great average gain is obtainable even in a case a 0 dB presents, the timing offset can be captured at a short time period.

Abstract: A carrier restoration apparatus for acquiring a frequency offset and tracking a phase jitter from a pass-band digital signal having the frequency offset and the phase jitter is disclosed. In the apparatus, a frequency acquisition PLL section for acquiring the frequency offset and a phase tracking PLL section for tracking the residual phase jitter are separately constructed, and the apparatus operates in two modes for first acquiring the frequency offset and then tracking the residual phase jitter. Thus, a rapid acquisition/tracking is performed so as to minimize the frequency offset and phase jitter of several hundred KHz produced from a tuner or an RF oscillator, and a high-reliability acquisition/tracking can be performed even under the low SNR and serious channel ISI (i.e., ghost).

Abstract: Disclosed is a quadrature amplitude modulation (QAM) receiver and a carrier recovery method which receive a signal modulated by the QAM method and recover the frequency offset and phase jitter of the carrier particularly using a weighted phase error inversely proportionate to the magnitude of the deciding signal character, as a result of which the phase jitter of the demodulated signal characters is constant in size irrespective of the magnitude of the deciding signal character. Consequently, acquisition/tracking can be rapidly achieved to minimize the frequency offset of several hundreds of KHz and the phase jitter generated from a tuner or an RF oscillator.