Digital receiver systems and clock recovery techniques for use in digital receiver systems are provided to implement asynchronous baud-rate clock recovery systems for high data rate serial receivers multilevel line modulation. A two-stage postcursor ISI equalization system is provided to efficiently emulate a 4-level DFE (decision feedback equalization) system, for example, while converting a 4-level equalized signal to s 2-level equalized signal. For example, a two stage postcursor ISI equalization system includes a DFE stage which operates on a most significant component of a given 4-level data symbol, followed by a DFFE (decision-feedforward equalizer) stage which operates on a least significant component of the given 4-level data symbol. In parallel with the DFFE stage, an estimate of the least significant component is subtracted from the equalized 4-level data symbol to convert the 4-level data symbol to a 2-level symbol.

A device includes a frequency offset (FO) estimation circuit and a frequency offset compensation circuit coupled with the frequency offset estimation circuit. The frequency offset compensation circuit is configured to (i) receive a continuous phase modulation (CPM) signal, (ii) receive, from the FO estimation circuit, an uncompensated frequency offset for a w.sup.th sampling window of the CPM signal, (iii) generate a frequency offset compensation value for a w+1.sup.st sampling window of the CPM signal based on the uncompensated frequency offset for the w.sup.th sampling window, (iv) adjust the CPM signal in the w+1.sup.st sampling window based on the frequency offset compensation value, and (v) provide the adjusted CPM signal to a filter.

Digital receiver systems and clock recovery techniques for use in digital receiver systems are provided to implement asynchronous baud-rate clock recovery systems for high data rate serial receivers multilevel line modulation. A two-stage postcursor ISI equalization system is provided to efficiently emulate a 4-level DFE (decision feedback equalization) system, for example, while converting a 4-level equalized signal to a 2-level equalized signal. For example, a two stage postcursor ISI equalization system includes a DFE stage which operates on a most significant component of a given 4-level data symbol, followed by a DFFE (decision-feedforward equalizer) stage which operates on a least significant component of the given 4-level data symbol. In parallel with the DFFE stage, an estimate of the least significant component is subtracted from the equalized 4-level data symbol to convert the 4-level data symbol to a 2-level symbol.

Digital receiver systems and clock recovery techniques for use in digital receiver systems are provided to implement asynchronous baud-rate clock recovery systems for high data rate serial receivers multilevel line modulation. A two-stage postcursor ISI equalization system is provided to efficiently emulate a 4-level DFE (decision feedback equalization) system, for example, while converting a 4-level equalized signal to s 2-level equalized signal. For example, a two stage postcursor ISI equalization system includes a DFE stage which operates on a most significant component of a given 4-level data symbol, followed by a DFFE (decision-feedforward equalizer) stage which operates on a least significant component of the given 4-level data symbol. In parallel with the DFFE stage, an estimate of the least significant component is subtracted from the equalized 4-level data symbol to convert the 4-level data symbol to a 2-level symbol.

Digital receiver systems and clock recovery techniques for use in digital receiver systems are provided to implement asynchronous baud-rate clock recovery systems for high data rate serial receivers multilevel line modulation. A two-stage postcursor ISI equalization system is provided to efficiently emulate a 4-level DFE (decision feedback equalization) system, for example, while converting a 4-level equalized signal to s 2-level equalized signal. For example, a two stage postcursor ISI equalization system includes a DFE stage which operates on a most significant component of a given 4-level data symbol, followed by a DFFE (decision-feedforward equalizer) stage which operates on a least significant component of the given 4-level data symbol. In parallel with the DFFE stage, an estimate of the least significant component is subtracted from the equalized 4-level data symbol to convert the 4-level data symbol to a 2-level symbol.

Digital receiver systems and clock recovery techniques for use in digital receiver systems are provided to implement asynchronous baud-rate clock recovery systems for high data rate serial receivers multilevel line modulation. A two-stage postcursor ISI equalization system is provided to efficiently emulate a 4-level DFE (decision feedback equalization) system, for example, while converting a 4-level equalized signal to s 2-level equalized signal. For example, a two stage postcursor ISI equalization system includes a DFE stage which operates on a most significant component of a given 4-level data symbol, followed by a DFFE (decision-feedforward equalizer) stage which operates on a least significant component of the given 4-level data symbol. In parallel with the DFFE stage, an estimate of the least significant component is subtracted from the equalized 4-level data symbol to convert the 4-level data symbol to a 2-level symbol.

Digital receiver systems and clock recovery techniques for use in digital receiver systems are provided to implement asynchronous baud-rate clock recovery systems for high data rate serial receivers multilevel line modulation. A two-stage postcursor ISI equalization system is provided to efficiently emulate a 4-level DFE (decision feedback equalization) system, for example, while converting a 4-level equalized signal to s 2-level equalized signal. For example, a two stage postcursor ISI equalization system includes a DFE stage which operates on a most significant component of a given 4-level data symbol, followed by a DFFE (decision-feedforward equalizer) stage which operates on a least significant component of the given 4-level data symbol. In parallel with the DFFE stage, an estimate of the least significant component is subtracted from the equalized 4-level data symbol to convert the 4-level data symbol to a 2-level symbol.

Embodiments of the present disclosure relate to methods and device for receiving PAM data stream. In an embodiment, a method comprises receiving a signal stream modulated with pulse amplitude modulation (PAM) associated with a plurality of bit patterns; determining boundary voltages for the plurality of bit patterns; and calibrating, based on the boundary voltages, a threshold voltage for use in recognition of the plurality of bit patterns. In this way, bit patterns may be accurately recognized based on the calibrated threshold voltage.

The present disclosure discloses a clock and data recovery circuit. A sampling circuit performs burst mode over-sampling on an input analog data signal according to a sampling timing in a burst mode to generate over-sampling results. A selection circuit determines neighboring two of the over-sampling results having opposite logic states in the burst mode to select data edge sampling results and data center sampling results interlaced with each other and having the same time period with input analog data signal from the over-sampling results accordingly to be output sampling results. A phase detection circuit performs phase detection according to the output sampling result to generate a phase locking direction. A phase adjusting circuit adjusts the sampling timing of the sampling circuit according to the phase locking direction to track the input analog data signal.

The present invention is designed to make possible adaptive modulation and coding (AMC) that supports high-order modulation schemes. The adaptive modulation and coding method of the present invention is an adaptive modulation and coding method for a downlink shared channel, and includes, in a user terminal, the steps of measuring channel quality based on a reference signal from the radio base station, acquiring a channel quality indicator to indicate the modulation scheme and the coding rate that are applicable to the downlink shared channel in the channel quality, from a table in which channel quality indicators, modulation schemes and coding rates are associated with each other, and transmitting the channel quality indicator to the radio base station, and the modulation schemes include a modulation scheme of a higher order than 64 QAM.