Loop Phase Research Articles

El viaje del paciente con fibromialgia en Latinoamérica

ObjectivesTo explore the patient journey of people with fibromyalgia (FM) in Latin American countries in order to identify problems in health care and other areas that may be resolvable. MethodsQualitative study with phenomenological and content analysis approach through focus groups and patient journey (Ux; User Experience) methodology. Nine virtual focus groups were conducted with FM patients and healthcare professionals in Argentina, Mexico and Colombia recruited from key informants and social networks. ResultsForty-three people participated (33 were clinicians and 10 were patients). The agents interacting with the patient in their disease journey are found in three spheres: healthcare (multiple medical specialists and other professionals), support and work life (including patient associations) and socioeconomic context. The line of the journey presents two large sections, two loops and a thin dashed line. The two major sections represent the time from first symptoms to medical visit (characterized by self-medication and denial) and the time from diagnosis to follow-up (characterized by high expectations and multiple contacts to make life changes that are not realized). The two loop phases include (1) succession of misdiagnoses and mistreatments and referrals to specialists and (2) new symptoms every so often, visits to specialists, diagnostic doubts, and impatience. Very few patients manage to reach the final phase of autonomy. ConclusionThe journey of a person with FM in Latin America is full of obstacles and loops. The desired goal is for all the agents involved to understand that self-management by the patient with FM is an essential part of success, and this can only be achieved with early access to resources and guidance from professionals.

Optimization of MPB for Sn Substituted Lead Bismuth Zirconate Titanate Thin Films by the Electromechanical Behavior Related to Energy Storage Capacity

In this article, we examined the electromechanical behavior of Sn-substituted Lead Bismuth Zirconate Titanate thin films (PBZST thin films). Using the pulsed laser deposition technique (PLD), the thin film growth parameters of bismuth-doped PZST close to MPB were adjusted by varying the ∼(Zr, Sn)/Ti ratios. Thin films (∼250 nm) with the stoichiometric formula Pb0.985Bi0.01(Zr0.7Sn0.3) x Ti1 – x O3, (x = 0.935, 0.940, 0.945, and 0.950) were grown on a Pt/TiO2/SiO2/Si substrate using PLD technique at optimized conditions. P-E loop confirms that MPB is near x = 0.945, and further PFM measurements also confirmed the same. Analyzing the PFM phase and amplitude hysteresis loops, local piezo-electric coefficient and remnant strain values were computed as d33 = 330 pm/V and 0.33 at the MPB composition (x = 0.945).

Harmonic Disturbance Compensation of a System With Long Dead-Time, Design and Experimental Validation

An internal model control scheme is proposed to compensate both a long dead-time of a system and a harmonic disturbance. The controller is based on an inversion of the first-order model used to approximate the system dynamics together with an input delay. Two other components of the controller consist of a filter and an additional delay by which the harmonic modes are targeted via adjusting the control loop gain and phase shift. The design of the filter-delay pair is fully analytical and the implementation of the scheme is straightforward. The main attention is paid to the complete compensation of a single-harmonic disturbance. Besides, an extension of the scheme is proposed to target a double harmonic disturbance. Increased attention is paid to the robustness aspects of the schemes. Outstanding performance in terms of harmonic disturbance compensation of the proposed schemes is demonstrated on a series of laboratory experiments.

Efficient Slicing of rational Bézier triangles for additive manufacturing

In additive manufacturing a three-dimensional model is created by adding successive layers of material. In recent years, several companies have emerged in the 3D’ printing market in the wake of their advantages over other manufacturing technologies. For one, the 3D printing pipeline allows for a more straightforward prototyping from 3D CAD models, resulting in a faster feedback loop in the prototyping phase thus allowing defects to be corrected more promptly when compared to traditional methods. Despite this, the method still has some shortcomings that can affect some use cases, such as the precision loss produced by the conversion of high-degree curved surfaces to simpler ones, such as polygonal meshes. The proposed method tackles this problem by proposing an efficient conversion-free way to sample points at the intersection between cutting planes and rational Bézier triangles of any degree to an arbitrary precision requirement.

Experimental study of two phase loop thermosyphons for hybrid solar systems

The use of thermosyphon technology to improve the efficiency of solar collectors, in thermal energy applications, has received literature increasing attention. The absence or decrease of solar radiation during nights or cloudy days can be compensated by another energy source, in the so-called hybrid solar systems. In the present paper, these systems, composed by two loop two-phase thermosyphons with independent evaporators, arranged in series and in parallel, are studied and compared between themselves for the first time in the literature. In the series configuration, the backup energy source feeds the evaporator of the auxiliary loop, which condenser is thermally connect to the evaporator of the main loop, also fed by the solar energy. In the parallel arrangement, both loops deliver the heat to a common condenser. These systems are tested under steady state conditions, keeping one or both evaporators active, representing the single (solar) or hybrid operation. The thermal resistance for both configurations are compared. Results of experiments simulating the operation throughout a typical day, including solar intermittency, are shown. In the solar intermittence tests, the backup evaporator, in the parallel arrangement, is able to compensate for solar absence 47% quicker, on average, when compared to the serial configuration. For the daily operation tests, the serial configuration is able to maintain the vapor temperature levels stable, when operating under different heat input rates between evaporators, while, in the parallel arrangement, vapor temperatures and thermal resistances varied significantly along the test.

Fast and robust DC link voltage control of single-phase grid-connected converters supporting 50 Hz and 60 Hz mains with universal magnitudes range

It is well-known that dynamics of single-phase grid-connected power converters employing PI or type-II DC link voltage controllers is limited by the maximum tolerable value of utility-side current total harmonic distortion (THD). Moreover, universal DC link voltage controller must be capable of supporting both 50 Hz and 60 Hz utilities and universal range of magnitudes (85Vrms–265Vrms). As a result, DC link crossover frequency value (and hence corresponding settling time) may vary significantly in case grid voltage magnitude variations are not compensated in the controller. In order to cope with the above-mentioned deficiencies, the paper suggests a design methodology for a novel dual-frequency-tuned utility magnitude insensitive plug-in disturbance observer (DOB), supporting universal utility frequencies and magnitudes so that the transient response of a grid-connected converter is improved without altering the existing PI or type-II DC link voltage controller coefficients. These characteristics are attained by robust modification of DC link voltage loop plant to possess notch-like properties around two frequencies of interest and treating the grid voltage magnitude value as non-measurable uncertainty translated into input disturbance and subsequently cancelled. Analytical design guidelines for obtaining PI + DOB controller coefficients are provided for desired values of utility-side current THD and DC link voltage loop phase margin (PM). Simulations and experimental results are provided to validate the feasibility of proposed design methodology.

Mechanism of Mongolian drug Naru-3 in initiation of neuroinflammation of neuropathic pain from MMP9/IL-1β signaling pathway

Neuropathic pain(NP) has similar phenotypes but different sequential neuroinflammatory mechanisms in the pathological process. It is of great significance to inhibit the initiation of neuroinflammation, which has become a new direction of NP treatment and drug development in recent years. Mongolian drug Naru-3 is clinically effective in the treatment of trigeminal neuralgia, sciatica, and other NPs in a short time, but its pharmacodynamic characteristics and mechanism of analgesia are still unclear. In this study, a spinal nerve ligation(SNL) model simulating clinical peripheral nerve injury was established and the efficacy and mechanism of Naru-3 in the treatment of NPs was discussed by means of behavioral detection, side effect evaluation, network analysis, and experimental verification. Pharmacodynamic results showed that Naru-3 increased the basic pain sensitivity threshold(mechanical hyperalgesia and thermal radiation hyperalgesia) in the initiation of SNL in animals and relieved spontaneous pain, however, there was no significant effect on the basic pain sensitivity threshold and motor coordination function of normal animals under physiological and pathological conditions. Meanwhile, the results of primary screening of target tissues showed that Naru-3 inhibited the second phase of injury-induced nociceptive response of formalin test in mice and reduced the expression of inflammatory factors in the spinal cord. Network analysis discovered that Naru-3 had synergy in the treatment of NP, and its mechanism was associated with core targets such as matrix metalloproteinase-9(MMP9) and interleukin-1β(IL-1β). The experiment further took the dorsal root ganglion(DRG) and the stage of patho-logical spinal cord as the research objects, focusing on the core targets of inducing microglial neuroinflammation. By means of Western blot, immunofluorescence, agonists, antagonists, behavior, etc., the mechanism of Naru-3 in exerting NP analgesia may be related to the negative regulation of the MMP9/IL-1β signaling pathway-mediated microglia p38/IL-1β inflammatory loop in the activation phase. The relevant research enriches the biological connotation of Naru-3 in the treatment of NP and provides references for clinical rational drug use.

Mapping the semi-nested community structure of 3D chromosome contact networks.

Mammalian DNA folds into 3D structures that facilitate and regulate genetic processes such as transcription, DNA repair, and epigenetics. Several insights derive from chromosome capture methods, such as Hi-C, which allow researchers to construct contact maps depicting 3D interactions among all DNA segment pairs. These maps show a complex cross-scale organization spanning megabase-pair compartments to short-ranged DNA loops. To better understand the organizing principles, several groups analyzed Hi-C data assuming a Russian-doll-like nested hierarchy where DNA regions of similar sizes merge into larger and larger structures. Apart from being a simple and appealing description, this model explains, e.g., the omnipresent chequerboard pattern seen in Hi-C maps, known as A/B compartments, and foreshadows the co-localization of some functionally similar DNA regions. However, while successful, this model is incompatible with the two competing mechanisms that seem to shape a significant part of the chromosomes' 3D organization: loop extrusion and phase separation. This paper aims to map out the chromosome's actual folding hierarchy from empirical data. To this end, we take advantage of Hi-C experiments and treat the measured DNA-DNA interactions as a weighted network. From such a network, we extract 3D communities using the generalized Louvain algorithm. This algorithm has a resolution parameter that allows us to scan seamlessly through the community size spectrum, from A/B compartments to topologically associated domains (TADs). By constructing a hierarchical tree connecting these communities, we find that chromosomes are more complex than a perfect hierarchy. Analyzing how communities nest relative to a simple folding model, we found that chromosomes exhibit a significant portion of nested and non-nested community pairs alongside considerable randomness. In addition, by examining nesting and chromatin types, we discovered that nested parts are often associated with active chromatin. These results highlight that cross-scale relationships will be essential components in models aiming to reach a deep understanding of the causal mechanisms of chromosome folding.

Practical Automatic Tuning of Lag-lead Compensators for Feedback Control Systems

This paper proposes a scheme for auto-tuning a lag-lead compensator to satisfy frequency-domain specifications of a feedback control system. Most previous studies proposed algorithms for tuning either lag or lead compensators. A study presented a self-tuning lag-lead compensator whose proportional gain, however, needs to be set manually. In contrast to previous studies, a fully automated tuning process for a lag-lead compensator is devised in this paper. In the proposed scheme, the plant's frequency responses at specific frequencies are first estimated, and an iterative algorithm adapts all controller parameters. To facilitate the estimation of high loop gain at a low frequency, a notch filter is introduced to the control loop while estimating this high low-frequency loop gain. Without this mechanism, a real-time data acquisition system of a wide dynamic range would be required. In addition to fulfilling the requirements for the low-frequency loop gain and phase margin, another feature of the proposed scheme is the satisfaction of the required gain-crossover frequency. However, the proposed method supposes that the frequency-domain specifications can be met for a plant using a lag-lead compensator, which is the plant's requirement for the proposed method. Experimental results for controlling a voice-coil motor are reported in this paper, showing that the proposed auto-tuner can practically provide a lag-lead compensated system satisfying frequency-domain performance requirements.

Implementation of a Wide Band and Low Noise Signal Generator Based on Phase Locked Loop

A signal generator, an essential electronic test instrument with versatile applications, finds its utility in various fields such as cellular communications, radar systems, microstrip antennas, and electronics labs. This research focuses on the simulation and design of a low-phase noise signal generatoroperating in frequency range of 35 MHz to 3 GHz . To accomplish this, an Atmega 328P microcontroller on an Arduino board was employed to control the synthesizer based on the Phase-Locked-Loop (PLL) concept. The signal generator’s performance was assessed, with particular emphasis on predicting and analyzing the phase noise generated by the PLL components. To ensure a robust system, a third-order loop filter was devised to effectively suppress spurs. Through simulation using the ADIsimPLLsimulation tool, optimal values for loop bandwidth (10 kHz) and phase margin (45°) were obtained. The chosen Phase-Locked-Loop chip for this implementation was the ADF4351, manufactured by Analog Devices. By conducting transient analysis, the time required for the PLL system to transition from the minimum to the maximum output frequency was determined. Furthermore, the characteristics of the generator’s signal were investigated in the frequency range of 35-100 MHz using a cathode ray oscilloscope, and for 101-3000 MHz using a spectrum analyzer. The phase noise levels were calculated at different frequencies (35 MHz, 387 MHz, 1 GHz, 2 GHz, and 2.9 GHz) and analyzed at varying offsets (1 kHz, 10 kHz,100 kHz, and 1 MHz). Comparatively, the experimental results indicated a higher level of phase noise than what was obtained through simulation. Notably, as the output frequency increased, there was a corresponding increase in the amount of phase noise. The maximum spur observedoccurred at the third harmonic, measuring -18.6 dBc, while the minimum spur appeared at the fourth harmonic, measuring -44.5 dBc.

Suppression of laser phase noise by using updated common arm locking

The space-borne gravitational wave (GW) detectors, e.g., LISA, TianQin, TaiJi, are designed to measure the GW in the low-frequency regime (0.1 mHz to 1 Hz). The arm length mismatches in the flying constellation prevent exact laser phase noise cancellation. For a typical Michelson interferometric design such as LISA, the two arms will differ by a few percent and the uncanceled fluctuation from the ultra-stable laser is about 5 orders larger than the sensitivity goal in the science band (0.1 mHz to 1 Hz). In this work, we try to resolve this discrepancy in real time by using an arm locking technique. Unlike the analysis in previous literatures, we use the subtraction of one closed loop phase meter output from another one at the main spacecraft to cancel the laser phase noise further. We find that, with a careful design of the arm locking controller, the laser phase noise can be suppressed below the level of secondary noises in most parts of the science band. We point out that since the nulls always exist in the presence the GW transfer function of Michelson interferometer, there is no need to move the nulls to outside the science band by using a complicated arm locking sensor. Then, a study on the Doppler frequency pulling for the system has been carried out, and the result suggests that the pulling rate can meet the requirement. Finally, a good agreement between the time-series simulation in Simulink and theoretical result indicates the feasibility of this scheme. Therefore, the suppression of laser phase noise can possibly be realized in real time with prestabilization and updated common arm locking techniques. Our work can provide a back-up strategy for the implementation of arm locking in future space-borne GW detectors.

Giant dynamic electromechanical response via field driven pseudo-ergodicity in nonergodic relaxors

Enhanced electromechanical response can commonly be found during the crossover from normal to relaxor ferroelectric state, making relaxors to be potential candidates for actuators. In this work, (Pb0.917La0.083)(Zr0.65Ti0.35)0.97925O3 ceramic was taken as a case study, which shows a critical nonergodic state with both double-like P-E loop and irreversible relaxor-normal ferroelectric phase after poling at room temperature. The low-hysteresis linear-like S-P2 loop, in-situ synchrotron X-ray diffraction and transmission electron microscope results suggest that the nonpolar relaxor state acts as a bridge during polarization reorientation process, accompanying which lattice strain contributes to 61.8% of the total strain. In other words, the transformation from normal ferroelectric to nonergodic relaxor state could be triggered by electric field through polarization contraction, which could change to be spontaneously with slightly increasing temperature in the nonergodic relaxor zone. Therefore, pseudo-ergodicity in nonergodic relaxors (i.e. reversible nonergodic-normal ferroelectric phase transition) driven by periodic electric field should be the main mechanism for obtaining large electrostrain close to the nonergodic-ergodic relaxor boundary. This work provides new insights into polarization reorientation process in relaxor ferroelectrics, especially phase instability in nonergodic relaxor zone approaching to freezing temperature.

Stopping Voltage‐Dependent PCM and RRAM‐Based Neuromorphic Characteristics of Germanium Telluride

AbstractRecently, phase change chalcogenides, such as monochalcogenides, are reported as switching materials for conduction‐bridge‐based memristors. However, the switching mechanism focused on the formation and rupture of an Ag filament during the SET and RESET, neglecting the contributions of the phase change phenomenon and the distribution and re‐distribution of germanium vacancies defects. The different thicknesses of germanium telluride (GeTe)‐based Ag/GeTe/Pt devices are investigated and the effectiveness of phase loops and defect loops future application in neuromorphic computing are explored. GeTe‐based devices with thicknesses of 70, 100, and 200 nm, are fabricated and their electrical characteristics are investigated. Highly reproducible phase change and defect‐based characteristics for a 100 nm‐thick GeTe device are obtained. However, 70 and 200 nm‐thick devices are unfavorable for the reliable memory characteristics. Upon further analysis of the Ag/GeTe/Pt device with 100 nm of GeTe, it is discovered that a state‐of‐the‐art dependency of phase loops and defect loops exists on the starting and stopping voltage sweeps applied on the top Ag electrode. These findings allow for a deeper understanding of the switching mechanism of monochalcogenide‐based conduction‐bridge memristors.

A Superflare on YZ Canis Minoris Observed by the Seimei Telescope and TESS: Red Asymmetry of Hα Emission Associated with White-light Emission

Active M-type stars are known to often produce superflares on the surface. Radiation from stellar (super)flares is important for exoplanet habitability, but the mechanisms are not well understood. In this paper, we report simultaneous optical spectroscopic and photometric observations of a stellar superflare on an active M dwarf, YZ Canis Minoris, with the 3.8 m Seimei telescope and the Transiting Exoplanet Survey Satellite. The flare bolometric energy is and the Hα energy is . The Hα emission line profile shows red asymmetry throughout the flare, with a duration of 4.6–5.1 hr. The velocity of the red asymmetry is ∼200–500 km s–1 and the line width of Hα broadens up to 34 ± 14 Å. The redshifted velocity and line width of Hα line decay more rapidly than the equivalent width, and their time evolutions are correlated with that of the white-light emission. This indicates the possibility of the white light, the Hα red asymmetry, and the Hα line broadening originating from nearly the same site, i.e., the dense chromospheric condensation region, heated by nonthermal electrons. On the other hand, the flux ratio of the redshifted excess components to the central components is enhanced one hr after the flare’s onset. This may be due to the main source of the red asymmetry changing to post-flare loops in the later phase of the flare.

Triple and double hysteresis loops in relaxor ferroelectric PMN-0.28PT crystals

The evolution of the dielectric hysteresis loops shape during heating of PMN-0.28PT single crystals possessing rhombohedral symmetry at room temperature was studied in the temperature range from room temperature to 200 °C. Revealed formation of the triple and double dielectric hysteresis loops in the relaxor phase upon switching by an electric field was explained by the influence of depolarizing fields arising at the interface of non-polar inclusions, and by the ineffective screening of polar clusters forming during transition through a percolation threshold, correspondingly. Further size decrease in the polar clusters due to heating led to their transformation to polar nanoregions.

Optimum Setting Algorithm Based PI Controller Tuning for SRF-PLL Used Grid Synchronization System

Synchronous reference frame-phase lock loop (SRF-PLL) is most widely used for grid synchronization applications. PLL structure typically consists of a phase detector (PD), loop filter (LF) and voltage control oscillator (VCO). Design and tuning of proportional-integral (PI) controller based LF is a changeling task under distorted grid voltage conditions. Conventional tuning methods such as symmetrical optimum (SO) and Ziegler-Nichols techniques are used to tune the PI controller, resulting in increased phase margin (PM) of the system. However, high bandwidth develops harmonics in the extracted signals under non-ideal grid conditions and affects the stability. In this research article, a new optimum setting algorithm is proposed to tune the PI controller and effective synchronization is achieved. The plant is reduced as a first-order plus dead time delay (FOPDT) model and critical gain; critical frequency of the open loop system transfer function is used to model the LF of the SRF PLL system. The controller parameters are derived such that minimization of time-weighted integral performance criteria is achieved and phase angle, frequency of the grid voltage is accurately extracted. The performance of the proposed optimum setting algorithm for the SRF-PLL grid synchronization technique is discussed in detail and simulation results are presented.

High-pressure properties of type V Natural Deep Eutectic Solvents: The case of menthol: thymol

This work reports a study on the properties of Menthol: Thymol 1: 1 type V Natural Deep Eutectic Solvent under high pressure conditions (up to 600 bar). The experimental PVT measurements allowed to calculate the most relevant thermophysical properties and its relationships with intermolecular forces and nanostructuring. PC-SAFT equation of state was considered for treating experimental thermodynamic data using a two-components approach, thus leading to a successful prediction of properties considering a single temperature-independent binary interaction parameter. The considered DESs shows atype I global phase behavior, with extremely narrow phase loop and low volatility. Classical Molecular Dynamics simulations provided a detailed nanoscopic picture of the fluid structuring and dynamics upon compression, with results showing minor changes in the nature and extension of hydrogen bonding and the main structural and dynamics features being maintained in the considered pressure range. The combined experimental and modelling study allowed a detailed characterization of the properties of this fluid under high pressure conditions.

A folded π-system with supramolecularly oriented dipoles: single-component piezoelectric relaxor with NLO activity.

Organic molecules with an active dipole moment have a natural propensity to align in an antiparallel fashion in the solid state, resulting in zero macroscopic polarization. This primary limitation makes the material unresponsive to switching with electric fields, mechanical forces, and to intense laser light. A single-component organic material that bestows macroscopic dipole-driven electro-mechanical and optical functions, e.g., piezoelectric, ferroelectric and nonlinear optical (NLO) activity, is unprecedented due to the design challenges imparted by crystal symmetry and dipole orientations. Herein we report a crystalline organic material that self-assembles with a polar order (P 1), and is endowed with a high piezoelectric coefficient (d 33-47 pm V-1), as well as ferroelectric and Debye-type relaxor properties. In addition, it shows second harmonic generation (SHG) activity, which is more than five times that of the benchmark potassium dihydrogen phosphate. Piezoelectric force microscopy (PFM) images validated electro-mechanical deformations. Piezoresponse force spectroscopy (PFS) studies confirmed a signature butterfly-like amplitude and a phase loop. To the best of our knowledge, this is the first report of a folded supramolecular π-system that manifests unidirectionally oriented dipoles and exhibits piezoelectricity, ferroelectricity, and has excellent ability to generate second harmonic light. These findings can herald new design possibilities based on folded architectures to explore opto-, electro- and mechano-responsive multifaceted functions.

Re-entrant transitions of locally stiff RNA chains in the presence of polycations leads to gelated architectures.

The liquid-liquid phase separation of protein and nucleic acid mixtures drives the formation of numerous membraneless compartments in cells. Temperature variation is commonly used for mapping condensate phase diagrams, which often display unique upper critical temperatures. Recent report on peptide-RNA mixtures has shown the existence of lower and upper critical solution temperatures, highlighting the importance of temperature-dependent solvent and ion-mediated forces. In the present work, we employ residue-level coarse-grained models of RNA and polycation peptide chains for simulating temperature-induced re-entrant transitions and shedding light on the role played by mobile ions, temperature-dependent dielectric permittivity, and local chain stiffness. We show that differences in bending rigidity can significantly modulate condensate topology leading to the formation of gelated or fibril like architectures. The study also finds that temperature dependence of water permittivity is generally sufficient for recapitulating experimentally observed closed loop and LCST phase diagrams of highly charged protein-RNA mixtures. However, we find that similar-looking closed-loop phase diagrams can correspond to vastly different condensate topologies.

Weak-light phase locking aided by frequency division phase meter for intersatellite laser interferometry

Weak light phase locking is an important part of intersatellite laser interference ranging. Phase-locked loop (PLL) is used to track the phase of heterodyne interference optical signal. Owing to shot noise, laser frequency and other kinds of noise, there is a phase difference between the internal PLL local oscillator and the heterodyne signal, while the phase detection range of the PLL is only one period. If the phase difference exceeds the phase detection range at a certain time, the local oscillator may enter the wrong operating point under feedback regulation, resulting in cycle clip, which leads to subsequent phase reconstruction errors. In this paper, a cycle clip diagnosis method based on the detection background of gravitational waves is proposed. Based on the original PLL, an auxiliary frequency phase divider with larger phase detection range is introduced, which can provide a basis for judging whether the cycle clip occurs in the PLL. In this paper, a digital weak-light PLL model is established to evaluate the influence of various noise. The theoretical spectral density of the error phase is given according to the two main kinds of noise (laser phase noise and particle noise). Considering the limited detection range of PLL, large error phase may lead to cycle clip, making the PLL work at the wrong locking point. A phase meter with smaller frequency division phase range can be used to solve this problem. First, the input heterodyne sine signal is converted into in-phase square wave N frequency division. Then the phase difference is determined by comparing the output signal with output signal reduced by 1/<i>N</i> through the time-to-degital converter (TDC) Based on the theory of PLL and noise, the theoretical model of frequency division phase meter is established. The simulation results show that the frequency division phase meter can realize a wide range of phase detection under the current theoretical framework and has the ability to judge the cycle clip of weak light phase locking. It can be used in the weak- light phase locking task represented by LISA.