Effects of Impulsive Noise on Phase-Locked Loop FM Demodulator

The effects of impulsive noise on phase-locked loop (PLL) FM demodulators is investigated. The PLL FM demodulator used for the experiments is basically a second order loop employing an active filter. The impulsive noise used for this work is ignition noise. Impulse response of the receiver is investigated and the PLL FM demodulator is digitally simulated. The response of the receiver employing the PLL FM demodulator used in the ground terminal to an input signal consisting of unmodulated carrier and impulses is investigated experimentally. The system margin is fouind to be degraded by about 10 dB.     

Acquisition Behavior of the Cross-Coupled Phase-Locked Loop FM Demodulator

In this work, the acquisition behavior of a cross-coupled phase-locked loop (CCPLL) FM demodulator capable of suppressing cochannel and adjacent channel interferers is examined. This novel detector consists of two phase-locked loop (PLL) demodulators interconnected in such a manner as to permit one PLL to lock onto and track the stronger received signal, while the other loop tracks and demodulates the weaker of two received signals. The demodulator has two separate outputs, namely, the outputs of each PLL, and thus possesses the capability of demodulating both the stronger as well as the weaker received signals even though they are cochannel and share the same frequency band. The transient response of the CCPLL system is obtained using computer-aided analysis of the defining coupled nonlinear differential equations. From these results, steady-state "stability regions" are derived which reveal that range of loop parameters where successful separation and demodulation of the received cochannel signals is assured. The CCPLL receiver has numerous technological applications in suppressing unintentional or intentional CW, AM, FM, and AM/FM interferers. Experimental results demonstrating such potential are included.     

基于相位产生载波技术的光纤解调器

提出一种基于相位产生载波技术的光纤解调器,它可以给光纤检波器阵列提供光能并实现对光纤检波器阵列中光波相位携带震动信息的接收和解调.光纤解调器由光发射机、光接收机、供电电路及通信电路组成.光发射机发出携带调制载波的光脉冲,经过光学复用后注入光纤检波器阵列.通过光接收机对光纤检波器阵列敏感到携带地震信息的光波进行接收,经过光波的解复用后,对干涉信号进行光电转换、数据采集及信号解调,最终得到原始的地震数据.通信电路与GPS授时器、主缆的通信光纤以及光接收机的输出连接,给解调后的数据打时标,并实现与相邻解调器或地震记录仪的通信.     

An Optical Phase-Locked Loop Photonic Integrated Circuit

We present the design, fabrication, and results from the first monolithically integrated optical phase-locked loop (OPLL) photonic integrated circuit (PIC) suitable for a variety of homodyne and offset phase locking applications. This InP-based PIC contains two sampled-grating distributed reflector (SG-DBR) lasers, semiconductor optical amplifiers (SOAs), phase modulators, balanced photodetectors, and multimode interference (MMI)-couplers and splitters. The SG-DBR lasers have more than 5 THz of frequency tuning range and can generate a coherent beat for a wide spectrum of frequencies. In addition, the SG-DBR lasers have large tuning sensitivities and do not exhibit any phase inversion over the frequency modulation bandwidths making them ideal for use as current controlled oscillators in feedback loops. These SG-DBR lasers have wide linewidths and require high feedback loop bandwidths in order to be used in OPLLs. This is made possible using photonic integration which provides low cost, easy to package compact loops with low feedback latencies. In this paper, we present two experiments to demonstrate proof-of-concept operation of the OPLL-PIC: homodyne locking and offset locking of the SG-DBR lasers.      

基于光纤环的光缓存器

提出了一种基于光纤环的光缓存器的结构,对结合半导体光放大器作光开关的此结构的物理模型进行了详细描述,并根据此模型分析了其增益、噪声、信噪比等方面的特性.     

一种基于Costas环的BPSK解调设计

设计了一种基于软件无线电思想的中频数字化接收机系统,该系统由数据采集模块、数字下变频（DDC）模块和数字解调模块构成。文中重点研究了基于Costas环的BPSK相干解调,并介绍了载波同步及BPSK解调的工作流程图,最后通过Simulink对BPSK解调原理进行了仿真验证。     

VSB解调器中的载波相位跟踪环

本文提出了一种专门用于数字ＶＳＢ解调的载波相位跟踪环，它实际上包括两个可视相互独立的子环，其一用于相位跟踪，另一用于幅度抖动补偿，在噪声和非噪声环境下，该环路均具有较好的性能，文中对此进行了理论分析和计算机仿真，结果表明，在ＨＤＴＶ地面传输系统约１５ｄｂ的信噪比门限下，该环路仍能可靠地工作。     

一种基于电荷泵锁相环的高精度数字移相方法

移相器是相控阵雷达的核心器件,随着工作频率的逐步提升,传统移相器的插入损耗和相位控制误差恶化严重,导致额外增加的功耗及波束性能变差.本文基于电荷泵锁相环（Charge Pump Phase-Locked Loop,CP-PLL）开展了高精度数字移相方法的研究.在分析CP-PLL相位数学模型与移相机理的基础上,提出了通过数控电流源的方法实现对输出信号相位的精确控制,建立电路模型开展仿真分析,并设计了实验电路模块,通过仿真和实测的对比验证了该方法的有效性和精确性,实现了移相步进优于1°,移相精度优于移相值的10%.该CP-PLL可通过作为本振信号或直接产生发射信号应用于相控阵雷达系统中,具有精度高、功耗低、易集成等特点,从而取代移相器,有效提升相控阵雷达的性能.     

一种具有相位噪声跟踪补偿的全数字锁相环频率合成器

为了实现频率合成器中的相位噪声跟踪补偿和降低全数字锁相环的复杂性,本文提出了一种新的基于全数字锁相环的频率合成器。它采用了一种低复杂度的数字鉴频鉴相器和非线性相位/频率判决电路以及数控振荡器,从而显著降低了硬件复杂性。同时结构中采用的非线性相位和频率判决电路能够很好地实现噪声跟踪和快速的相位/频率捕获,数控振荡器能够获得高的频率分辨率(大约6kHz)和大的线性频率调谐范围。通过采用90nm CMOS工艺制造的ADPLL实验结果表明,本文所提出的基于全数字锁相环的频率合成器能够实现从100kHz到6MHz的可控环路带宽和相当好的带内相位噪声跟踪性能。     

Properties of Optical Phase-Locked Loop Based on Four Wave Mixing in Semiconductor Laser Amplifiers

In this paper, the properties of the optical phase-locked loop(PLL) based on the four-wave mixing in the semiconductor laser amplifiers (SLAs) are discussed. The components that achieve the function of detecting the bit phase of the input optical signal are concerned and discussed in detail together as a function module named as the optical bit phase detector referred to the general electronic PLL. Therefore, most of the properties of the optical PLL can be analyzed by applying the general phase-locked theory. Here the stability of the optical PLL is discussed. It's shown that the variance of input signal power in the practical application will cause optical PLL system unstable because of its long loop delay. The influence on the output phase jitter of the optical PLL is also investigated.     

A 20-Gb/s Quadrature Phase-Shift-Keying Real-Time Coherent System Based on a Subcarrier Optical Phase-Locked Loop

A 20-Gb/s quadrature phase-shift keying (QPSK) homodyne coherent system was analyzed and experimentally demonstrated. This system is based on subcarrier optical phase-locked loop (SC-OPLL) and it works in real time. In this letter, we present a brief optical receiver analysis and the transmission system performance in terms of simulations and experimental results. We also show that the QPSK system works but it is affected by loop propagation delay effects due to the prototypal implementation. The delay loop effects can be mitigated by an SC-OPLL integrated realization.     

Phase Noise in Millimeter Wave Phase-Locked Loop with Mixer

In order to estimate the phase noise of millimetre wave (MMW) phase-locked oscillator (PLO), the phase noise relation of signals in MMW phase-locked loop (PLL) with frequency conversion is analyzed. The signals include output of MMW PLO, intermediate frequency (IF) output of harmonic mixer and output of microwave oscillator serving as local oscillator (LO). A method to estimate the phase noise of MMW PLO is presented, which is based on the phase noise of LO and IF. At the same time, a W-band PLO is achieved, and the phase noise values of the three signals are measured. It is shown that the experimental result is well coincident with the analysis of phase noise relation.     

基于噪声分析的低抖动全数字锁相环的设计

设计了一个用于时钟产生的全数字锁相环(ADPLL),其数控振荡器(DCO)采用9级环形振荡器,每级延迟单元的延迟时间均是可调的,各级倒相器的尺寸经过精确设计.该电路基于SMIC 0.13μm CMOS工艺,采用1.2 V电源供电,整个芯片的面积为0.13485 mm2.示波器测试结果表明,锁相环的捕获频率范围为100～500 MHz,输出频率为202.75 MHz时,峰-峰值抖动为133 ps,RMS抖动为46 ps.     

基于随机解调器压缩采样的宽带频谱检测方法

宽带频谱检测的目的是完成对宽频段内信号的检测。在Nyquist采样理论下,为瞬时覆盖这么宽的带宽会对模数转换器（ADC,analog—to-digital）的采样率提出过高要求。研究了基于随机解调器压缩采样的宽带频谱检测方法。该方法能够以低于Nyquist采样率的速率完成对宽频段的采样,降低了ADC的负担。仿真结果表明,在频谱满足稀疏性的条件下,所研究的方法能够较准确检测宽频段内的各个信号。     

光电反馈对光锁相环性能的改善

本文分析了自差型光电反馈对半导体激光锁相环(OPLL)性能的影响,给出了自差型光电反馈半导体激光器(LD)作为 OPLL 本振时的相位传递函数,指出它不是理想积分型的。也讨论了这时 OPLL 的最佳自然频率和最小噪声方差。     

基于锁定时间分析的锁相环频率合成器

提出了一种新的针对采用二阶无源滤波器的锁相环频率合成器锁定时间的估算公式,并通过仿真软件及实测结果对该公式进行了验证。基于该估算公式,设计了一种具有快速锁定功能的锁相环频率合成器。实验结果表明该锁相环频率合成器锁定时间小于7μs,具有快速锁定的功能。同时该锁相环还具有良好的相位噪声性能,对于32GHz输出信号相位噪声为-72dBc/Hz@1kHz以及-90dBc/Hz@1MHz。     

Design, Analysis and Experimental Testing of BPSK Homodyne Receivers Based on Subcarrier Optical Phase-Locked Loop

The analysis of a subcarrier optical phase-locked loop (SC-OPLL) is carried out in order to optimize phase-locking performance. A new parameters optimization procedure, useful for OPLL design, is demonstrated theoretically and experimentally. An SC-OPLL based on this procedure has been realized, so a pilot carrier SC-OPLL and a nonlinear SC-OPLL optical receiver have been experimentally constructed and tested. An 8B/10B line coding is employed for pilot carrier SC-OPLL receiver in order to improve performance and a new architecture of decision-driven PLL is experimentally demonstrated.     

Range Extension of a Phase-Locked Loop

The capture capability of a type of hybrid-locked loop (HLL) in a noisy environment has been shown to be better than that of a conventional phase-locked loop (PLL). An approximate method of estimating the locking range and the locking time of the HLL in the noisy environment has been presented. Also given are the experimental results in partial support of the conclusions of the analysis.     

External Synchronization of 160-GHz Optical Beat Signal by Optical Phase-Locked Loop Technique

We have synchronized a 160-GHz optical beat signal with a 40-GHz reference optical pulse train by using an optical phase-locked loop (OPLL). The OPLL consists of an optical beat signal source, comprising a pair of three-electrode distributed feedback laser diodes that works as a voltage controlled oscillator, and an all-optical phase detector based on the two-photon absorption in a silicon avalanche photodiode. Phase-locking operation is confirmed through phase-error measurement and cross-correlation trace measurement. The residual timing jitter of the 160-GHz optical beat signal relative to the reference pulse train, in the bandwidth of 80 MHz, is measured to be as small as 126 fs