An all-optical phase detector by amplitude modulation of the local field in a Rydberg atom-based mixer

Recently,a Rydberg atom-based mixer was developed to measure the phase of a radio frequency(RF)field.The phase of the signal RF(SIG RF)field is down-converted directly to the phase of a beat signal created by the presence of a local RF(LO RF)field.In this study,we propose that the Rydberg atom-based mixer can be converted to an all-optical phase detector by amplitude modulation(AM)of the LO RF field;that is,the phase of the SIG RF field is related to both the amplitude and phase of the beat signal.When the AM frequency of the LO RF field is the same as the frequency of the beat signal,the beat signal will further interfere with the AM of the LO RF field inside the atom,and then the amplitude of the beat signal is related to the phase of the SIG RF field.The amplitude of the beat signal and the phase of the SIG RF field show a linear relationship within the range of 0 toπ/2 when the phase of the AM is set with a differenceπ/4 from the phase of the LO RF field.The minimum phase resolution can be as small as 0.6°by optimizing the experimental conditions according to a simple theoretical model.This study will expand and contribute to the development of RF measurement devices based on Rydberg atoms.

Design of Digital Multi-Radian Phase Detector on J-TEXT

A real time system used to detect phase difference between two sinusoidal signals is proposed in this paper. The system is designed to process the phase signal of the far-infrared （FIR） hydrogen cyanide （HCN） interferometer on J-TEXT. It is based on zero-crossing detection and makes use of the digital circuit. Compared with a traditional zero-crossing phase detector, it doesn＇t need to sacrifice the time resolution to expand the phase range. The phase difference is divided into two parts, the integer part and the fraction part. In each detecting cycle, they are detected separately. It outputs digital signals that are more stable for transmission. A prototype was built on J-TEXT using discrete components. A practical method is proposed to deal with the counting error caused by the deviation of electronic components in manufacture. Reasonable results were obtained on the prototype. The phase resolution reaches 2π/64 in test, and can still be improved by raising the clock frequency.

Robust CMOS phase frequency detector for high speed and low jitter charge pump PLL

In order to improve the performance of the existing phase frequency detectors （PFDs）, a systematical analysis of the existing PFDs is presented. Based on the circuit architecture, both classifications and comparisons are made. A new robust CMOS phase frequency detector for a high speed and low jitter charge pump phrase-locked loop （PLL） is designed. The proposed PFD consists of two rising-edge triggered dynamic D flip-flops, two positive-edge detectors and delaying units and two OR gates. It adopts two reset mechanisms to avoid the LIP and DN signals to be logic-1 simultaneously. Thus, any current mismatch of the charge pump circuit will not worsen the performance of the PLL. Furthermore, it has hardly any dead-zone phenomenon in phase characteristic. Simulations with ADS are performed based on a TSMC 0. 18-μm CMOS process with a 1.8-V supply voltage. According to the theoretical analyses and simulation results, the proposed PFD shows a satisfactory performance with a high operation frequency （≈ 1 GHz）, a wide phase-detection range [ ± 2π], a near zero dead-zone （ 〈 0. 1 ps）, high reliability, low phase jitter, low power consumption （ ≈100 μW） and small circuit complexity.

fs-level laser–RF synchronization with a fiber-loop optical-microwave phase detector

In order to improve the precision of the laser–radio-frequency（RF） synchronization system from sub-picosecond to femtosecond（fs）, a synchronization system between a picosecond laser and a 1.3 GHz RF generator has been developed based on a fiber-loop optical-microwave phase detector（FLOM-PD）. Synchronization with fs-level（3.8 fs） rms jitter, integrated from 10 Hz to 1 MHz, is achieved for the first time, to the best of our knowledge, in this kind of configuration. This system will be used for the superconducting RF accelerator at Peking University.

Design of IREDM System with a DSP Phase Detector

The design and realization of a new generation of infra-red electronic distance measurement (IR EDM) system are presented.A DSP(Digital Signal Process) phase detector based on high speed analog-to-digital converter and DSP technique has been designed,in order to improve the precision and reliability of IR EDM system.As a result,the EDM system developed with a DSP phase detector has a precision of 3 mm in the measuring range of 2 km.

Design of 0.5V low-voltage phase and frequency detector for frequency synthesizer in wireless sensor networks

Based on 0.13μm complementary metal-oxide-semiconductor（CMOS） technology,a phase and frequency detector（PFD） is designed with a low supply voltage of 0.5V for frequency synthesizers used in wireless sensor networks（WSNs）.The PFD can compare the frequency and phase differences of input signals and deliver a signal voltage proportional to the difference.Low threshold transistors are used in the circuits since a power supply of 0.5V is adopted.A pulse latched structure is also used in the circuits in order to increase both the detection range of phase errors and the maximum operation frequency.In experiments,a phase error with a range from-358° to 358° is measured when the input signal frequency is 2MHz.The PFD has a faster acquisition speed compared with conventional digital PFDs.When the input signals are at a frequency of 2MHz with zero phase error,the circuits have a power consumption of 1.8[KG＊8]μW,and the maximum operation frequency is 1.25GHz.

Passive round-robin differential-quadrature-phase-shift quantum key distribution scheme with untrusted detectors

In this paper, we proposed the scheme for a passive round-robin differential-phase-shift quantum key distribution（RRDPS-QKD） set-up based on the principle of Hong–Ou–Mandel interference. Our scheme requires two legitimate parties to prepare their signal state with two different non-orthogonal bases instead of single in original protocol. Incorporating this characteristic, we establish the level of security of our protocol under the intercept-resend attack and demonstrate its detector-flaw-immune feature. Furthermore, we show that our scheme not only inherits the merit of better tolerance of bit errors and finite-sized-key effects but can be implemented using hardware similar to the measurement device independent QKD（MDI-QKD）. This ensures good compatibility with the current commonly used quantum system.

离子色谱技术研究进展

离子色谱技术作为分析无机离子的首选方法,还可实现小分子极性化合物、氨基酸、糖类等生物样品的分析。近年来,离子色谱技术快速发展,广泛应用在环境监测、食品分析、生物医药、农业、地质等多个领域。针对离子色谱技术的综述多是探讨离子色谱技术在环境、烟草、药品、食品等领域的应用进展,而关注离子色谱技术发展动态的研究报道相对较少。专利文献蕴含科技文献未曾报道的技术研发信息,对于归纳总结前沿技术走向具有重要意义。基于全球范围内离子色谱相关技术专利数据,从淋洗液发生装置、色谱柱固定相、离子色谱抑制器、检测器等方面综述离子色谱分析技术的研究进展,旨为国内离子色谱技术创新发展提供参考与依据。研究表明,全球离子色谱技术研究发展迅速,核心技术及基础研究主要分布在美国和日本,超高压淋洗液发生器、优化供电方式的自动再生电解抑制器及温控稳定的检测器是离子色谱领域新近研究方向,围绕固定相的研究侧重于提高离子交换容量,提高分析速度,改善离子色谱柱效、选择性与亲水性等方面性能。

Automatic IQ Phase Calibration Design in a 2.4GHz Direct Conversion Receiver

An automatic IQ phase calibration method implemented in a 2.4GHz direct conversion receiver is proposed. It uses a delay locked loop （DLL） with a proposed quadrature phase detector to greatly reduce the phase error. The receiver is fabricated in a 0.18μm CMOS process. Measurements show that the IQ phase error can be calibrated within 1°,which satisfies the system requirement.

PLL DEMODULATION TECHNIQUE FOR M-RAY POSITION PHASE SHIFT KEYING

The paper presents a kind of transmission system which employs M-ary Position Phase Shift Keying(MPPSK) to send data and Phase Locked Loop(PLL) based techniques for data retrieve.With a single PLL, MPPSK demodulation is achieved, as well as carrier recovery and symbol synchronization.Firstly, MPPSK modulation method is briefly introduced.2PPSK's PSD expression is given with its optimization result.Orthogonal Phase Detector(PD) and static threshold are used for the purpose of wider phase range and simplicity in demodulation.The data rate is alterable, which is 4.65 kbps for 2PPSK and 9.3 kbps for 4PPSK in the paper.Then some indicative comparisons in Signal to Noise Ratio Symbol Error Rate(SNR-SER) are made among 2PPSK, 3PPSK and 4PPSK, of which 4PPSK has proved to be optimal in ten slots each symbol conditions.And finally, it is demonstrated by system simulations that lower than 10-4 Symbol Error Rate(SER) performance can be obtained at 13 dB symbol SNR.

Phase control system for SSRF linac

The design of phase control system in Shanghai Synchrotron Radiation Facility (SSRF) linac is presented in this paper. And digital phase detecting algorithm, the key for phase control system, is fully described. The testing results for phase control system in 100MeV linac are discussed in detail.

Study and ICH validation of a reverse-phase liquid chromatographic method for the quantification of the intact monoclonal antibody cetuximab

Cetuximab （CTX） is a potent chimeric mouse/human monoclonal antibody （mAb） approved worldwide for treatment of metastatic colorectal cancer. Among the various biological and physical analyses per- formed for full study on this biopharmaceutic, the determination of the concentration preparations throughout manufacturing and subsequent handling in hospital is particularly relevant. In the present work, the study and validation of a method for quantifying intact CTX by reverse-phase high-perfor- mance liquid chromatography with diode array detection （（RP）HPLC/DAD） is presented. With that end, we checked the performance of a chromatographic method for quantifying CTX and conducted a study to validate the method as stability-indicating in accordance with the International Conference on Harmo- nization guidelines （ICH） for biotechnological drugs; therefore, we evaluated linearity, accuracy, preci- sion, detection and quantification limits, robustness and system suitability. The specificity of the method and the robustness of the mAb formulation against external stress factors were estimated by compre- hensive chromatographic analysis by subjecting CTX to several informative stress conditions. As de- monstrated, the method is rapid, accurate, and reproducible for CTX quantification. It was also suc- cessfully used to quantify CTX in a long-term stability study performed under hospital conditions.

IDENTIFICATION OF PHASE ERROR BY MULTI-SAMPLING DIGITAL TANLOCKED LOOP(MS-DTL)

A multisampling technique was introduced to the phase error detector of Conventional Digital Tanlocked Loop(C DTL). In this new technique a number of samples ( M ) were taken at nonuniform intervals within one period of the input signal. The novel system is called Multisampling Digital Tanlocked loop(MS DTL). The simulated model on the computer shows that for M =4, the system has a faster locking speed and wider locking in range compared with C DTL.

一种适用于亚采样锁相环的高鲁棒性辅助锁定电路

当前的研究表明,基于亚采样相位检测器(Sub-Sampling Phase Detectors,SSPD)的锁相环(Phase-Locked Loop,PLL)相较传统锁相环架构可以实现显著降低的带内相位噪声。然而,在片上系统(Systems on Chip,SOCs)应用中,PLL容易受到衬底或电源耦合的干扰,这很可能会导致PLL失去锁定,且可能无法恢复。针对此问题,提出一种将辅助锁频环(Frequency-Locked Loop,FLL)和数字锁定检测器(Digital Lock Detector,DLD)相结合的适用于亚采样锁相环(Sub-Sampling Phase-Locked Loop,SSPLL)的高鲁棒性辅助锁定电路。仿真结果表明:与传统SSPLL相比,所提出的电路极大提升了PLL对衬底或电源干扰的鲁棒性,同时保持了其低相位噪声的优点,这对于SSPLL在大规模生产和应用中的可靠性具有重要意义。

低抖动电荷泵锁相环设计及其Simulink建模仿真

随着集成电路工艺技术的进步,电路工作频率越来越高,对时钟信号的抖动和相噪也提出了更高的要求。针对锁相环电路参数多、结构复杂、瞬态仿真耗时长等问题,通过建立电荷泵锁相环系统环路数学模型,并运用MATLAB/Simulink对其进行负反馈系统建模,实现对电荷泵锁相环的快速动态仿真。在TSMC 65 nm CMOS工艺节点下,完成了锁相环的电路设计、版图绘制、物理验证并提取寄生参数及后仿真,得到一款典型值:输入频率为30 MHz,锁定频率1.5 GHz的低抖动电荷泵锁相环。后仿真结果表明该PLL电路性能指标良好,在典型值条件下,PLL的锁定时间为10μs,锁定时峰峰值抖动为2.68 ps,时钟信号占空比为45%。

Extraction and Determination of Three Chlorophenols by Hollow Fiber Liquid Phase Microextraction - Spectrophotometric Analysis, and Evaluation Procedures Using Mean Centering of Ratio Spectra Method

A method termed hollow fiber liquid phase microextraction (HF-LPME) was utilized to extract three chlo- rophenols, 2-chlorophenol (2-CP), 2,4-dichlorophenol (2,4-DCP) and 2,4,6- trichlorophenol (2,4,6-TCP), separately from water. The extracted chlorophenols were then separated, identified, and quantified by UV-Vis spectrophotometry with photodiode array detection (UV-Vis/DAD). In the study, experimental con-ditions such as organic phase identity, acceptor phase volume, sample agitation, extraction time, acceptor phase NaOH concentration, donor phase HCl concentration, salt addition, and UV absorption wavelength were optimized. The statistical parameters of the proposed method were investigated under the selected con-ditions. The analytical characteristics of the method such as detection limit, accuracy, precision, relative standard deviation (R.S.D.) and relative standard error (R.S.E.) was calculated. The results showed that the proposed method is simple, rapid, accurate and precise for the analysis of ternary mixtures.

基于副边解耦极板的电容式无线电能传输系统拾取端失谐评估

对于电容式无线电能传输(CWPT)系统,准确评估拾取端回路的失谐程度是维持系统谐振稳定的前提。然而,由于系统拾取端的感应电压无法被直接观测,难以通过测量感应电压和回路电流间的相位差来评估拾取端回路的失谐程度。文中提出一种能够间接测量拾取端感应电压相位信息,评估拾取端回路失谐程度的CWPT系统。基于Z参数建立三端口CWPT系统的数学模型和等效电路,并依托该模型提出一种基于副边解耦极板的耦合机构。分析在感应电压测量和失谐程度评估过程中存在的误差,提出拾取端回路失谐程度的评估校正方法。搭建了带有副边解耦极板的CWPT系统原理样机,实验结果表明,拾取端谐振时的失谐程度评估误差不超过1Ω,拾取端感性/容性失谐时的失谐程度评估误差分别小于2%和5%。

一种面向SDH应用的低抖动全数字锁相环

为使同步数字体系(Synchronous Digital Hierarchy,SDH)设备获得高质量的时钟信号源,提出了一种使用8 kHz输入时钟信号综合出低抖动9.72 MHz输出时钟信号的全数字锁相环(All-Digital Phase-Locked Loop,ADPLL)。该ADPLL使用了一种新型的滤波式鉴相器,通过特定的算法实现了对极低占空比周期信号的相位检测和比较,并结合数控振荡器对输出时钟信号进行调整,使得9.72 MHz输出时钟信号具备低抖动特性。该设计在Xilinx的Pynq-Z2上进行了验证,测试结果表明,ADPLL锁定范围为7.99836 kHz~8.00164 kHz,相应的输出时钟信号范围为9.7180074 MHz~9.7219926 MHz,9.72 MHz输出时钟信号峰峰值抖动仅为1.6 ns@9.72 MHz,约为0.016UI,远低于ITU-T G.813规范的要求(0.5UI)。

激光外差探测阵列互相关相干累积法

针对粗糙目标导致本振光与信号光波前失配这一技术难题,提出一种基于序列移位与互相关的用于检测微弱外差信号的相干累积法。该方法利用阵列探测器的阵列信号进行互相关运算,将外差信号频谱幅值作为目标函数,快速准确地估计最佳序列偏移量和计算相位调整量,搭建了一套基于高速摄像机阵列探测器的光外差探测系统。仿真分析和实验结果表明,该方法应用于主动光外差探测领域时对相位补偿的精确度更高,信号处理时间可提高到毫秒量级。

便携式生物电阻抗测量系统的设计与应用

生物电阻抗可用于人体成分测量,具有重要的临床意义与应用价值,现阶段的生物电阻抗测量设备仍存在成本高昂、设备笨重的问题。因此,提出了一种便携式生物电阻抗测量系统,其由控制电路、电流发射电路与阻抗测量电路组成,通过微控制器STC12C5A60S2对直接数字频率合成器AD9833、鉴相器AD8302等微型模块的有效控制,实现对不同频率下人体生物电阻抗的精准稳定测量。研究结果表明,该系统在设计复杂度与实现成本远低于商用人体生物电阻抗仪的前提下,实现了与之类似的测量精确度,有望为生物电阻抗测量装置的小型化、便携化、低成本化发展提供新的思路。