共查询到19条相似文献,搜索用时 312 毫秒
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在高功率条件下,由于受到多种因素的影响,单频光纤激光器输出激光的谱线宽度大幅展宽,输出激光的稳定性也不高。相位调制光外差稳频(PDH)技术在高功率条件下可以实现高频率稳定性。为实现对中心波长为1 064 nm的单频光纤激光器的稳频,理论分析了PDH稳频系统的原理并搭建PDH稳频系统。实验发现100 MHz相位调制光外差信号的检测是稳频系统的关键。实验中首先利用自行设计的探测器前置放大电路,基于Si探测器,实现了信号的探测和放大;其次,设计解调电路,通过将光电转换后的信号与参考信号进行混频实现解调,得到鉴频曲线,实现对光外差信号的检测。 相似文献
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《中国激光》2016,(3)
分析了传统Pound-Drever-Hall(PDH)激光稳频方法的工作原理,设计了一种基于正交解调原理的PDH激光稳频方案。该方案采用直接数字频率合成器同时产生两路频率均为10 MHz的正弦和余弦信号,其中正弦信号分为两路:一路用于驱动电光相位调制器以产生相位边带,另一路与余弦信号一起作为相位解调的参考信号。经相位调制后的激光束耦合进入F-P参考腔,所产生的光外差干涉信号由光电探测器进行探测,其输出信号分别与两路正交参考信号进行混频,经低通滤波后得到误差信号的两个正交分量,二者经A/D转换后进入微处理器进行正交相敏检波运算,即可得到PDH稳频系统的误差信号。建立了正交解调PDH激光鉴频实验系统,对F-P参考腔的腔长进行线性扫描,观察到了鉴频曲线,其鉴频灵敏度为1.82 V/MHz,最大频率变化量为5.48 MHz。实验结果表明,所设计的正交解调PDH稳频方案可行。 相似文献
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干涉型集成光学加速度计信号处理及SOPC设计 总被引:2,自引:0,他引:2
介绍了集成光学芯片、光纤质量块简谐振子和可编程片上系统(SOPC)混合集成光学加速度计的设计方法。采用迈克尔逊干涉方法实现加速度信号光相位调制,综合交流相位跟踪零差补偿技术(PTAC)和合成外差信号解调技术(SHSD)补偿误差并解调出加速度信号,应用SOPC技术设计和实现数字信号处理(DSP)系统,同时实现DSP和智能化数据传输接口并行工作,使系统实时、线性地跟踪到加速度信号。系统设计灵敏度达4.8902V/g。实际测量灵敏度达4.62V/g,工作频带10~1066Hz。 相似文献
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由于激光外差干涉测量系统光机平台无法模拟多普勒频移,并且商用信号发生器无法实现多种类、高复杂度的星间外差干涉信号模拟,不能对空间引力波探测的相位计进行全面测试。通过分析外差干涉信号的特性,研究信号模拟系统的实现原理及方法,设计了空间引力波探测激光外差干涉信号模拟系统。首先,应用直接数字合成器(DDS)模拟外差干涉信号。其次,通过频率偏移方式模拟多普勒效应,应用混合同余算法生成散粒噪声并调制到外差干涉信号中。最后,基于FPGA搭建系统硬件平台,通过示波器及频谱分析仪分析生成信号的时频特性。实验结果表明,信号模拟系统在2~20 MHz的频率范围内杂波抑制度为?53 dBc,谐波(二次)抑制达到?47 dBc,生成信号的时频特性符合理论预期,满足空间引力波探测相位计的地面测试需求。 相似文献
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为了能够快速精确地测量波片相位延迟量和快轴方位角,实现测量系统的集成化和自动化,设计了基于弹光调制技术与数字锁相技术相结合的波片测量系统。采用弹光调制器对检测激光进行调制,运用基于FPGA的数字锁相技术提取调制信号的一、二倍频项,利用优化算法解调出波片相位延迟量和快轴方位角,步进电机带动波片转动使快轴到达零度位置,相位延迟量由LCD显示出来。搭建了实验系统,并对1/4波片进行了测量。实验结果表明:该系统对1/4波片快轴方位角的测量精度优于0.31,相位延迟量的测量精度和重复度分别优于99.47%和0.14。测量系统的弹光调制器驱动信号、电机驱动信号、数据运算都由FPGA控制,实现了光机电一体化。 相似文献
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为了对抽运源的稳频技术做出对比和选择,采用内调制技术和相位调制光外差技术,以周期性极化KTP晶体作为非线性晶体,实现了894.6nm连续光两镜驻波倍频腔的稳频运转。结果表明,在不同注入光功率下,用这两种方法锁定倍频腔后获得的蓝光功率基本相同;在最大注入光功率为350mW时,获得178mW的447.3nm蓝光,相应的转化效率为50.8%;在最大注入光功率下,利用内调制技术和相位调制光外差稳频技术获得的蓝光在2h内功率起伏分别为3.4%和2.3%。该研究对获得稳定输出的447.3nm蓝光用来制备铯原子D1线的非经典光的实验是有帮助的。 相似文献
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Onodera R. Ishii Y. Ohde N. Takahashi Y. Yoshino T. 《Lightwave Technology, Journal of》1995,13(4):675-681
A dynamic interferometer with a frequency-ramped laser diode (LD) has been constructed that is based on an optical heterodyne technique. Effect of LD power change on the optical heterodyne interferometry has been investigated theoretically and experimentally. A general formulation of the interferometry has been presented in which the demodulation scheme is analyzed in the frequency domain by Fourier-transforming a beat signal. Phase errors caused by the LD-power variation alter sinusoidally with the same period as the interference beat signal. The error can be eliminated by using an amplitude-stabilized, frequency-modulated laser diode source in the interferometer. The stabilization of the LD amplitude can be achieved by a feedback system with a superluminescent diode as an external light-power controller 相似文献
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无人机着陆采用微波着陆系统(MLS)作导航系统具有很大优势,针对MLS信号高精度2DPSK解调和AM解调的要求,提出了一种基于FPGA的中频数字化解调方案;分析了改进科斯塔斯环法(Costas)实现载波同步及数字正交AM解调的原理;重点介绍了利用坐标旋转数字式计算机(CORDIC)算法实现数控振荡器(NCO)、鉴相、AM解调关键模块的设计过程。该算法采用流水线结构,只有加法和移位,资源消耗低、效率高、易于FPGA实现。应用VHDL硬件语言进行编程,采用同一电路完成了2DPSK解调和AM解调。仿真结果证明了方案的可行性和准确性,该方案可广泛应用于多种数字中频接收机,具有广阔的应用前景。 相似文献
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This paper describes the design and performance of anM ary frequency shift keyed (FSK) signaling and demodulation scheme for an optical communication system using semiconductor lasers and heterodyne detection. Frequency or phase noise in semiconductor lasers causes spectral spreading, producing a nonzero linewidth laser signal. This degrades communication performance when compared to a system using an ideal laser with zero linewidth. We present estimates of the bit error rate (BER) performance ofM -ary frequency shift keying (FSK) with noncoherent demodulation in the presence of white Gaussian frequency noise and additive channel noise. This is typical of an optical system using semiconductor lasers and heterodyne detection. Estimates use the union-Chernoff bound with a simplified channel model to predict the effects of frequency noise. Two effects of frequency noise are identified: signal attenuation or suppression, and crosstalk. These cause an offset in the BER curve from the BER in the absence of frequency noise, and an error rate floor, respectively. The error rate floor is lower than previously predicted. When performance is not crosstalk limited,M -ary FSK is found to perform better than binary FSK with the same system bandwidth constraints, as would be predicted if ideal lasers are used. Theoretical results are compared with Monte Carlo simulations of the system. 相似文献
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Passive demodulation of optical interferometric sensors 总被引:1,自引:0,他引:1
Two techniques for passive (no-feedback) demodulation of signals from a remote two-beam interferometric sensor are discussed. Termed "synthetic heterodyne" and "quadrature recombination," both methods are based on forced sinusoidal modulation of phase within the interferometer. If the phase modulation is generated by linearly proportional frequency modulation of the laser light source, then the interferometer, deployed by means of optical fibers, can be a completely passive remote sensor, and an array of identical sensors can be operated from one light source. The former technique, proposed by Cole, Danver, and Bucaro permits standard FM demodulation. The latter technique, proposed by Cable and Green, employs arithmetic operations that are appropriate to digital implementation. Constraints on application of the technique, especially frequency distribution and amplitude of phase noise (out-of-band) versus signal amplitude (in-band), are analyzed and an implementation is proposed that is consistent with Contemporary analog-to-digital conversion technology. 相似文献
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GMSK信号是一种连续相位调制方式,由于它具有较好的功率效率和频谱利用率,因此在无线通信领域得到广泛的应用。在此给出一种适合于数字化处理的突发GMSK调制信号的相干解调方式,利用基于FFT的载波频偏及符号时钟误差联合估计算法,实现前导字检测以及频偏和符号定时误差的估计和补偿。采用基于匹配滤波的前向位同步技术实现位同步,对存在残留频偏误差情况下该相干解调系统的解调性能进行了计算机仿真分析。仿真和实验表明,该解调方法具有良好的误码性能。 相似文献