38 results about "Full Rate" patented technology

The invention discloses an optimization method for secure transmission of an active STAR-RIS assisted RSMA communication system. The optimization method mainly comprises the following steps: S1, constructing an active STAR-RIS assisted multi-input single-output RSMA communication system; s2, the base station transmits the information to legal users in the system through the active STAR-RIS; s3, the base station sends the artificial interference noise while sending the useful signal; constructing an optimization equation for maximizing system private information and safety rate based on beam forming, artificial noise, an active STAR-RIS power amplification matrix, an amplitude matrix and a phase shift matrix as optimization parameters; s4, performing proper conversion on a non-convex objective function and constraints by using a WMMSE criterion, and performing decoupling solution on an optimization problem by using an AO algorithm; s5, updating an auxiliary variable introduced by the WMMSE algorithm according to the closed expression; s6, using an SCA algorithm to optimize and update beamforming and artificial noise of the base station, and a power amplification matrix and an amplitude matrix of the active STAR-RIS; and S7, adopting an SCA algorithm and a PDD algorithm to optimize and update the phase shift matrix of the active STAR-RIS. According to the invention, the security of the communication system is obviously improved.

The invention relates to an electric power communication system optimization technology, in particular to a physical layer security optimization method and equipment for a full-duplex multicarrier power line communication system, and the method combines a full-duplex technology and a time domain artificial noise auxiliary security strategy to construct a multicarrier power line communication system model with a relay; generating a safety rate maximization problem, designing a set of convex approximation method, and performing conversion and simplification of a non-convex optimization problem; designing an iterative solution algorithm, and jointly optimizing the confidential data of the source node, the confidential data of the relay node and the artificial noise power distribution matrix; and optimizing the physical layer safety performance of the full-duplex multi-carrier power line communication system based on the solved power distribution matrix. According to the communication scheme and the solved power distribution vector, the safety performance of the power line communication system is optimized, the limitation of the number of power transmission cables in the power line communication system is avoided, the safety rate maximization of the total transmitting power domain can be realized, and the technical problem that data in an existing multi-hop power line communication system is prone to leakage is solved.

The invention discloses a transmitter based on a high-speed low-power-consumption data serialization and driving circuit, and the transmitter comprises a low-speed serialization module which is used for serializing 32 paths of input parallel low-speed data into 4 paths under the control of a multi-phase clock signal; the FFE 4-tap generation module is used for performing delay operation on the four paths of data under the control of a clock signal to obtain four groups of tap data; and the high-speed 4: 1 MUX hybrid SST driving module is provided with 2N first slices, the N first slices comprise K slices of PRE taps, L slices of MAIN taps, J slices of POST1 taps and H slices of POST2 taps, and the driving module is used for generating full-rate differential data according to the four groups of tap data and switching signals provided externally and realizing impedance matching of an output end. According to the invention, the number of used triggers can be reduced, full-rate nodes in the circuit are eliminated, the power consumption is reduced, the complexity of simulating the FFE is relatively low, and different channel losses can be compensated.

The invention discloses an intelligent transmission surface and intelligent reflection surface combined assisted robust secure transmission method, which considers the condition that a direct channel between a BS and a Bob is shielded by an obstacle, utilizes a bounded error model to perform modeling on uncertainty of an eavesdropping reflection channel, and aims at weighting and safety rate maximization. A multi-user power distribution coefficient, ITS beam forming and IRS phase shifting are jointly optimized by taking base station transmitting power constraints, ITS transmitting element constraints and unit modulus IRS phase shifting constraints into consideration, and the unit modulus constraints of the IRS phase shifting are processed by using continuous convex approximation, alternating optimization and Cauchy-Schwartz inequality and adopting a penalty method. According to the robust beam forming method, signal transmission under the non-ideal condition is considered, and the robust beam forming method is suitable for an ITS and IRS combined auxiliary system.

The invention discloses a finite block length secure transmission method and system based on communication perception integration, and relates to the technical field of communication. Comprising the following steps: S1, constructing a system model, determining an optimization problem, analyzing a safe transmission rate capable of reaching a limited block length, and constructing a safe rate maximization problem; s2, designing an optimization scheme: decomposing the non-convex optimization problem in the S1 into three sub-problems, namely uplink transmission power distribution of IoE equipment, sensing signal design and joint sensing and communication receiving beam forming optimization, converting each sub-problem into a solvable convex optimization problem, and respectively solving the solvable convex optimization problem, and obtaining the solution of the original problem through an alternate iteration method until the algorithm converges or reaches the maximum iteration times. According to the method, a potential threat source is identified more accurately by utilizing a sensing data auxiliary system, and the technologies of beam forming, artificial noise and the like are utilized, so that the secure transmission between legal users is ensured, the quality of a received signal of an eavesdropper is reduced, and the secure fusion of a communication function and a sensing function is realized.

The invention discloses an optimization method of active STAR-RIS auxiliary NOMA (Non-Orthogonal Multiple Access) secure communication transmission. The method comprises the following steps: S1, constructing an active STAR-RIS auxiliary uplink NOMA secure wireless communication system; and S2, the link of the user 1-BS and the link of the user 2-BS are blocked due to obstacles or a long distance, and the legal user transmits information to the base station of the receiving end through STAR-RIS. S3, in order to improve the safety of the system, the base station sends the useful signal and the artificial interference noise at the same time; under the scene that the total emission energy of a base station is limited, an optimization equation which is based on beam forming, artificial noise and IRS phase shift parameters and is used for maximizing the system safety rate sum of optimization parameters is constructed. And performing decoupling optimization solution on active beam forming, artificial noise and IRS phase shift parameters of the base station based on an alternating optimization algorithm. According to the invention, the total safety rate of the system can be obviously improved.

The invention relates to a distortion noise-based RIS auxiliary passive communication system robust transmission method, which belongs to the technical field of low-power-consumption Internet of Things, and comprises the following steps: S1, initializing parameters of a distortion noise-based RIS auxiliary passive communication system; s2, according to the maximum transmitting power of a base station, the minimum safety rate of backscattering equipment, energy collection, transmission time, the phase shift of an RIS reflection unit and channel uncertainty constraints, constructing a resource optimization model based on channel uncertainty by taking the maximization of the total energy efficiency of the RIS assisted passive communication system based on distortion noise as an optimization target; s3, converting the resource allocation model containing the channel uncertainty into a deterministic optimization problem model by utilizing a worst criterion and binary Taylor expansion; and then an alternating optimization method, a variable substitution method and a continuous convex approximation method are used for solving, so that the optimal total energy efficiency is obtained.

A method of operating a memory device includes receiving, from a memory controller, an operation command that is synchronized with a clock signal, receiving a data clock signal having a full-rate frequency and a synchronization pattern provided by at least one of a plurality of data signals. The clock signal and the data clock signal are then synchronized using a synchronization operation based on the synchronization pattern. The data clock signal may be received after a first delay time passes from a time point at which the operation command is received. The first delay time is a delay time necessary to prepare the synchronization operation.

The invention provides an FRIS-assisted physical layer security communication method and system, the physical layer security communication system comprises a base station and an FRIS, the surface available area of the FRIS is divided into a plurality of sub-areas, each sub-area comprises a plurality of reflection units, all the reflection units in each sub-area form a sub-array, and each sub-array comprises a plurality of reflection units. Only one reflection unit in each subarray is selected and activated, and the activated reflection unit is used as an activation unit for reflecting a transmission signal of the base station to a legal user; the method comprises the steps that an optimization problem is solved, the optimization problem takes maximization of the safety rate of a legal user as an optimization target, constant modulus constraint, phase shift discrete constraint and activation unit position constraint are taken as constraint conditions, and an activation unit position and a passive beam forming variable are obtained. Compared with the traditional RIS, the FRIS-assisted physical layer security communication method and system can significantly improve the PLS performance of the system, thereby improving the security communication level of the system.

The application belongs to the technical field of communication, and particularly relates to a full-rate communication system, method, terminal and storage medium based on 5G, which comprises a control module, an acquisition module, a communication module and a power module for powering the whole system; the control module is connected to external equipment through the communication module; the communication module comprises a low-rate communication unit, a medium-rate communication unit and a high-rate communication unit; the system integrates the low-rate, medium-rate and high-rate communication units, can intelligently select the most suitable communication mode for data transmission according to the size and type of target data, the flexibility ensures that the terminal equipment can work at the optimal communication rate and power consumption in different use scenarios, and avoids the problem of shortened battery life caused by long-time use of high-power communication technology in the traditional scheme. Meanwhile, since the communication rate can be flexibly switched according to actual needs, the system also effectively reduces the flow cost of the SIM card.

The invention discloses a shore ship adaptive communication method, system and device based on reconfigurable intelligent surface assistance, and relates to the technical field of communication and deep reinforcement learning. The method comprises the following steps: determining a target equivalent channel, an eavesdropping equivalent channel and a diagonal phase shift matrix to be optimized according to a first RIS phased array and a second RIS phased array; determining a base station channel and a superposition channel according to the diagonal phase shift matrix to be optimized, the target equivalent channel and the eavesdropping equivalent channel; determining a total safety rate according to the to-be-optimized beam forming vector and transmission data of the second base station, the to-be-optimized artificial noise vector of the first base station, a base station channel and a superposition channel; constructing constraint conditions according to the maximum transmitting power of the first base station, the to-be-optimized beam forming vector, the to-be-optimized artificial noise vector and the to-be-optimized diagonal phase shift matrix; and based on a multi-strategy value network fusion algorithm, solving a target optimization result by taking the maximum total safety rate as a target and taking a constraint condition as a constraint.

The application discloses a kind of joint security and covert communication methods based on dynamic mode switching mechanism, which first executes scene task loading and parameter initialization, obtains the task parameter set and channel state information of current transmission period, obtains the reflection coefficient matrix of intelligent reflecting surface.Secondly, according to the channel state information and the reflection coefficient matrix, the candidate parameter set of security communication mode and covert communication mode is generated respectively, and the executable strategy set and the performance evaluation result of two modes are obtained.Finally, according to the performance evaluation result of security communication mode and the preset switching threshold, dynamic switching is carried out between security communication mode and covert communication mode, the system performance of safety rate calculation current period is obtained, and the task parameter of next transmission period is updated.The application solves the problem that security communication and covert communication are usually designed separately, and it is difficult to unify and coordinate control according to real-time channel state, exposure risk and transmission demand.

This invention provides an analog adaptive three-tap decision feedback equalizer circuit for high-speed SerDes, which splits the input signal into three paths, reducing the frequency. Compared to full-rate decision feedback equalizers, this invention reduces timing requirements and the design complexity of the corresponding phase-locked loop (PLL) providing the clock, making it applicable to higher data transmission rates. Furthermore, the analog adaptive loop allows for appropriate adjustment of the multiplier tap coefficients, more effectively eliminating inter-symbol interference. Compared to adaptive circuits in mixed-signal circuits that require counters and DACs, this invention has lower design complexity, better convergence, and meets the requirements of high-speed transmission.

The invention discloses a general inductance integrated waveform design method for realizing physical layer security and target perception of an RSMA system. According to the invention, the base station mainly adopts the RSMA public signal and the artificial noise signal to cooperatively serve as the sensing signal so as to realize target sensing. In the aspect of perception, estimation of azimuth angles and reflection coefficients is mainly carried out, and Cramer-Rao bound is adopted for representation. For a communication link of a known eavesdropper, optimization design is carried out on an emission matrix by taking maximization of a safety rate and safety capacity as a target, and for the condition that an eavesdropper channel is unknown, optimization design is carried out on an emission vector by taking minimization of energy required by communication and perception as a target. Firstly, an optimization problem conforming to a scene is constructed, then, an original problem is converted into a convex problem based on an SCA method, rank 1 constraint is converted into a penalty function in an optimization target, finally, an iterative method is adopted for solving, and eigenvalue decomposition is performed on an optimization solution conforming to conditions to obtain emission vectors. Compared with a mode of sensing by adopting a proprietary sensing signal and an RSMA public signal, the method provided by the invention has better safety energy efficiency on the premise of ensuring safe transmission.

The invention discloses a transmitting device based on a DSP-DAC framework and a high-speed serial communication system, and relates to the field of serial communication, in the device, a digital processing unit processes a signal to be transmitted based on multi-tap FIR feedforward equalization to obtain B paths of parallel A-bit data signals; the low-speed data processing module obtains C paths of parallel A-bit data signals; the differential-pulse generation module under the ith group of DAC slices receives C paths of parallel ith-bit data signals so as to obtain C paths of parallel pulse signals, the merging and serializing driving module performs merging and serializing according to the C paths of parallel pulse signals, driving corresponding to the ith group of slice weight is performed through an SST driving structure so as to output a serialized differential signal corresponding to the ith bit, and the serial differential signal corresponds to the ith bit. And a target serialized differential signal is obtained through superposition. According to the scheme, parallel-to-serial processing and output driving are combined to set the merging-serializing driving module, and a full-rate signal node is only limited at a final output stage, so that the front-end circuit design is simplified, and high speed and completeness of an output signal are ensured.

A method for generating clock signals includes dividing an input clock signal to obtain a first in-phase output clock signal, dividing an inverted version of the input clock signal to obtain a first quadrature output clock signal, delaying edges in the input clock signal to obtain a second quadrature output clock signal, selecting a full-rate output to provide a multiphase output clock in a first mode of operation, and selecting a half-rate output to provide the multiphase output clock in a second mode of operation. The first quadrature output clock signal is a quadrature version of the first in-phase output clock signal. The first in-phase output clock signal and the first quadrature output clock signal are included in the full-rate output. The second quadrature output clock signal is included in the half-rate output and is a quadrature version of the input clock signal.

The present invention discloses a method for maximizing the security rate of an artificial noise-assisted covert communication system, which relates to the field of communication security technology. The method comprises obtaining channel fading coefficients from a friendly source node to a friendly destination node, from a friendly source node to an eavesdropping node, from a friendly source node to an enemy detection node, from a friendly destination node to an eavesdropping node, and from a friendly destination node to an enemy detection node, and a loop self-interference channel fading coefficient of the friendly destination node; calculating the transmission rates of a main link and an eavesdropping link respectively according to the channel fading coefficients to obtain the security rate of the system; performing binary hypothesis testing and concealment measurement analysis on the communication process between friendly nodes to obtain concealment constraint conditions; constructing a system security rate maximization problem for jointly optimizing signal transmission power and artificial noise power with the communication concealment between friendly nodes as a constraint; and solving the optimization problem using an iterative algorithm based on successive convex approximation to obtain the maximum security rate of the system.

This invention discloses a high-efficiency odd-rate clock data recovery circuit. It uses switched capacitors to implement the phase detector, effectively reducing the phase detector's power consumption and area. Furthermore, its equivalent resistance and subsequent small-loop filter capacitor achieve a large loop bandwidth independent of PVT, effectively increasing the frequency acquisition range, eliminating the frequency discrimination loop, reducing lock-in time, suppressing the phase noise of the ring oscillator, and improving the jitter tolerance performance of the CDR loop. In addition, the retiming of random data employs an odd-rate demultiplexing structure, reducing the operating frequency of the N-stage ring oscillator, buffer, and retimer to 1 / N of the full-rate structure. This effectively reduces the power consumption and parasitic effects of the CDR circuit. The use of a frequency accumulator cleverly multiplies the odd-rate sub-rate clock by N to a full-rate clock without introducing excessive power consumption and area, where N is an odd number.

The utility model discloses multi-channel full-rate bit error rate test equipment, which comprises an MCU (Microprogrammed Control Unit) controller, a pseudo-random code pattern generator, a pseudo-random code pattern detector, a clock source circuit, a signal shaping circuit and a power supply circuit, the MCU controller, the clock source circuit and the signal shaping circuit are connected with the pseudo-random code pattern generator and the detector. And the MCU controller receives a user instruction to set test parameters, flexible adjustment can be performed according to different requirements, and the universality and applicability of the equipment are enhanced. The clock source circuit provides a time reference for signal processing, ensures accurate generation and synchronous detection of pseudo-random code patterns, and improves the statistical accuracy of bit error rates. The signal shaping circuit balances and filters input signals, compensates transmission distortion, improves signal quality, reduces misjudgment caused by distortion, and improves error rate calculation precision. The pseudo-random code pattern generator and the detector count the number of error codes and calculate the error rate, and provide key data for evaluating the transmission quality of a communication system.

The invention discloses a high-efficiency low-computing-power physical layer secure communication method and device based on an intelligent metasurface and a medium. The method comprises the steps that S1, channel matrixes h1 and H2 between a base station and an expected user and between the base station and an eavesdropper are input; s2, setting the number of iterations I, and initializing the number of iterations i = 0 and u (0); s3, randomly generating S alternative RIS phase shift matrixes according to the ui; s4, obtaining an equivalent channel matrix according to the channel matrix h1 and an alternative RIS phase shift matrix, and calculating a corresponding precoding matrix W; s5, calculating the maximum reachable safety rate of each alternative RIS phase shift matrix according to the equivalent channel matrix, the channel matrix H2 and the precoding matrix W; s6, arranging the alternative RIS phase shift matrixes theta in a descending order according to the maximum reachable safety rate; s7, selecting S'elite 'RIS phase shift matrixes theta with the maximum safety rate, S8, updating u (i + 1) based on the selected S' elite 'RIS phase shift matrixes theta, and S9, outputting a quasi-optimal RIS phase shift matrix theta for realizing high-efficiency low-computing-power physical layer safety communication.

A decision feedback equalizer providing pulse width adjustment, particularly comprising a pulse width adjustment circuit for receiving a plurality of amplified inputs obtained by corresponding different reference values, and adjusting the pulse width of the amplified inputs to conform to a 3-order adjustment signal according to a 3-order enable signal enabled by an initialization circuit, wherein a plurality of even-numbered channel signals are generated corresponding to a third-order even-numbered channel selection signal, a plurality of odd-numbered channel signals are generated corresponding to a third-order odd-numbered channel selection signal, even-numbered channel and odd-numbered channel half-rate sampling is carried out, first-order operation for reviewing the previous bit and second-order operation for reviewing the previous two bits are realized, and then full-rate output is obtained through combination.

The present invention claims a method for maximizing the minimum safe rate of a drone-assisted non-orthogonal multiple access technology NOMA backscatter communication system. The method takes into account the fairness between backscatterers BD and the difficulty of eavesdroppers to obtain instantaneous channel state information CSI, and satisfies the transmission power of the drone, the decoding order of serial interference cancellation SIC, and the reflection coefficient of BD, energy collection EH and the safety interruption probability constraints. The method realizes the maximization of the minimum safe rate of the drone-assisted NOMA backscatter communication system. The present invention first processes the safety interruption probability constraint by referencing auxiliary variables, and then obtains the optimal solution by using methods such as block coordinate descent, variable substitution, penalty function, scaling and continuous convex approximation SCA. The present invention takes into account the fairness between BDs and the actual eavesdropping scenario at the same time, and has good practicality and feasibility.

The disclosed systems, structures, and methods relate to encoding and decoding information for transmission over a communication channel. The encoding method includes: distributing the information bits among m parallel polar codes such that each of the m parallel polar codes includes a subset of the information bits; dividing the subset of information bits in each of the m parallel polar codes into a guard information portion and a full-rate information portion; guarding the information bits within the guard information portion of each of the m parallel polar codes; setting multiple freeze bits in each of the m parallel polar codes; and generating a polar codeword for each of the m parallel polar codes.

The invention provides a full-space PLS transmission method and system for an STAR-RIS auxiliary wireless communication system. In the STAR-RIS auxiliary wireless communication system, a reflection coefficient and a transmission coefficient of an STAR-RIS and precoding vectors allocated by a base station to a safe user and a public user are obtained by solving a non-convex optimization problem. Wherein the non-convex optimization problem takes the maximization of the weight sum of the safety rate of a safety user and the reachable rate of a public user as an optimization target and takes the power of a base station as a constraint condition; the security rate of the secure user is obtained by performing large-scale system analysis on the average security rate of the secure user. According to the scheme provided by the invention, under the assistance of STAR-RIS, robust full-space physical layer secure transmission can be realized.

The utility model discloses full-rate bit error rate testing equipment which comprises a clock source, an MCU (Microprogrammed Control Unit) control and a power supply circuit. Wherein the clock source circuit plays a key role, and a core chip U1 of the clock source circuit works cooperatively with a plurality of capacitors, resistors and diodes. A plurality of pins of the chip U1 are connected with a capacitor to be grounded, an internal circuit is stabilized, and a stable environment is created for clock signal generation. Accurate clock signals are obtained or output through pins connected with the clock generator, and a stable time reference is provided for error rate testing. The accurate clock signal enables the test equipment to be more accurate when detecting the change of the data transmission signal, effectively avoids the misjudgment caused by the inaccurate clock, remarkably improves the accuracy of the error rate test, and guarantees the reliability of the test result.

A STAR-RIS assisted secure communication method, device and medium for countering cooperative multi-eavesdropping in the present invention solve the problem of improving the system sum-security rate in the case where multiple malicious users cooperate with each other to eavesdrop on legitimate users in a communication system. The present invention includes: S1, initializing the beamforming vectors of each legitimate user and the transmission-reflection coefficients of the STAR-RIS; S2, fixing the transmission-reflection coefficients, constraining the rate upper bound of malicious eavesdropping users, and obtaining the beamforming vectors by maximizing the legitimate user rate; S3, fixing the beamforming vectors, relaxing the feasible region of the transmission-reflection coefficients, and obtaining the solution of the transmission-reflection coefficients by using the penalty concave-convex process; S4, repeating S2 and S3 until the system sum-security rate converges. The present invention is applicable to a STAR-RIS assisted secure communication system in a cooperative multi-eavesdropping scenario, can cover general single-eavesdropping models and independent multi-eavesdropping models, and improves the system sum-security rate.

The invention discloses an IRS-assisted safety rate maximization design method under outage probability constraint, and belongs to the technical field of wireless communication. In order to ensure that the outage probability of the secure transmission system is within a tolerable range, a probability constraint is introduced into the design of the secure transmission system in a transmitter, an intelligent reflecting surface, an expected receiver and a stealer communication system model; a safety rate maximization problem containing probability constraints is provided, wherein phase shift, power distribution and transmission rate are coupled in an objective function and the probability constraints. The method comprises the following steps of: firstly, converting a probability constraint which is difficult to process into a deterministic constraint by means of exponential distribution of received signal power; then, an alternating optimization (AO) method is used for fixing a beam forming matrix of a transmitter and a phase shift matrix of an intelligent reflecting surface respectively, and through inequality transformation and Rayleigh quotient solving, the problem that under the condition that a channel is uncertain, probability constraints of coupling variables are difficult to process, and the probability constraints of the coupling variables are difficult to process is well solved. And the problems of optimal phase shift, power distribution and transmission rate design of secure transmission are solved.

A single-particle reinforced half-rate decision feedback equalization circuit is based on a half-rate decision feedback equalizer circuit structure, and adopts an adder, a decision device, a three-stage multi-node upset resistant latch, an either-or data selector, a buffer and an adaptive controller. After entering the circuit, an input signal is divided into an odd path and an even path which are respectively balanced. A delay signal generated by the multi-node upset resistant latch unit acts with the tap coefficient and then is sent to the adder. Wherein the tap coefficient is determined by the adaptive controller circuit using an adaptive algorithm. Finally, the two paths of half-rate data are integrated into one path of full-rate data to be output. A half-rate structure is adopted, so that the problem that a traditional equalization circuit has strict requirements on a clock is solved. The multi-node upset resistant latch unit is added in the circuit, so that the influence of single event upset on intersymbol interference in a space environment is avoided. And the stability and accuracy of data storage are ensured.

The application discloses a near-far field robust security communication fusion method based on a non-orthogonal multiple access technology, and comprises the following steps: setting a channel model of a near field ISAC system, and acquiring a reachable rate of a user decoded by an eavesdropper; taking an error matched by a weighted beam pattern as an optimization target, setting an optimization problem P1 for the error matched by the weighted beam pattern; and adopting an S-Procedure technology and an alternating optimization technology to split the optimization problem P1 into sub-problems 1-3, and solving the optimization problem P1. The application sets a security rate of a user under eavesdropper interference, establishes a robust near field user model under the condition that an eavesdropping channel has a channel error, and under the influence of the error, guarantees that the near field user has a basic successful decoding rate and a minimum security rate requirement, and jointly optimizes a user service quality and a potential target sensing performance.

The present invention discloses a quarter-rate four-level pulse amplitude modulation (PAM4) clock and data recovery circuit based on three-way phase detection and majority voting, which relates to the field of high-speed communications. The circuit comprises three quarter-rate phase detectors and a majority voter, which identify and determine the phase difference between three thermometer codes and a multiphase clock, reducing phase jitter caused by discrete zero crossings and improving the rate of the PAM4 clock and data recovery circuit. A quadrature voltage-controlled oscillator and a phase interpolator dynamically adjust the output frequency of the quadrature voltage-controlled oscillator to provide a sampling multiphase clock for the quarter-rate phase detector. Three 1:4 multiplexers and a pulse generator use a four-phase pulse signal with a 25% duty cycle as an enable signal to reconstruct four retimed quarter-rate NRZ signals into a single full-rate NRZ signal. The PAM4 clock and data recovery circuit proposed in the present invention has the advantages of high speed, high efficiency, low jitter, and high precision, and has broad application prospects in the field of communication transceivers.