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Journal articles on the topic 'Optical phase locked loops'

Author: Grafiati

Published: 6 September 2023

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1

Naglič, L., L. Pavlovič, B. Batagelj, and M. Vidmar. "Improved phase detector for electro-optical phase-locked loops." Electronics Letters 44, no. 12 (2008): 758. http://dx.doi.org/10.1049/el:20080069.

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2

Satyan, Naresh, Wei Liang, Firooz Aflatouni, Amnon Yariv, Anthony Kewitsch, George Rakuljic, and Hossein Hashemi. "Phase-Controlled Apertures Using Heterodyne Optical Phase-Locked Loops." IEEE Photonics Technology Letters 20, no. 11 (June 2008): 897–99. http://dx.doi.org/10.1109/lpt.2008.922335.

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3

XU Nan, 许楠, 刘立人 LIU Liren, 刘德安 LIU Dean, and 周煜 ZHOU Yu. "Optical Phase Locked Loops in Inter-Satellites Coherent Optical Communications." Laser & Optoelectronics Progress 45, no. 4 (2008): 25–33. http://dx.doi.org/10.3788/lop20084504.0025.

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4

Kim, J., F. X. Kärtner, and F. Ludwig. "Balanced optical-microwave phase detectors for optoelectronic phase-locked loops." Optics Letters 31, no. 24 (November 22, 2006): 3659. http://dx.doi.org/10.1364/ol.31.003659.

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5

Liang, Wei, Naresh Satyan, Firooz Aflatouni, Amnon Yariv, Anthony Kewitsch, George Rakuljic, and Hossein Hashemi. "Coherent beam combining with multilevel optical phase-locked loops." Journal of the Optical Society of America B 24, no. 12 (November 8, 2007): 2930. http://dx.doi.org/10.1364/josab.24.002930.

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6

Zhao Xin, 赵馨, 董岩 Dong Yan, 刘洋 Liu Yang, 宋延嵩 Song Yansong, and 常帅 Chang Shuai. "Optical Phase Locked Loop Technology Based on Multistage Compound Loops." Acta Optica Sinica 38, no. 5 (2018): 0506002. http://dx.doi.org/10.3788/aos201838.0506002.

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7

Zhang, Zhao. "CMOS phase-locked loops in ISSCC 2023." Journal of Semiconductors 44, no. 5 (May 1, 2023): 050205. http://dx.doi.org/10.1088/1674-4926/44/5/050205.

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8

., Madhumita Bhattacharya. "A SCHEME FOR OPTICAL PULSE GENERATION USING OPTOELECTRONIC PHASE LOCKED LOOPS." International Journal of Research in Engineering and Technology 03, no. 03 (March 25, 2014): 349–52. http://dx.doi.org/10.15623/ijret.2014.0303064.

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9

Tsyrulnikova, L. A., B. P. Sudeev, and A. R. Safin. "Wave Analogs of Media Based on Phase Locked Loops." Journal of the Russian Universities. Radioelectronics 23, no. 3 (July 21, 2020): 32–40. http://dx.doi.org/10.32603/1993-8985-2020-23-3-32-40.

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Introduction. At present, phase locked loops (PLLs) are widely used: from optimal signal detection and frequency synthesis to automatic control of phase distribution in phased scanned arrays. One of the simplest structures is a multi-stage (chain) PLL, which may contain a specially selected multi-connected control circuit. Such cascaded PLLs have wide application in solving a number of tasks of the theory of optimal estimates, multi-position phase telegraphy, in synchronizing of many tunable generators while preserving specified phase relations between their oscillations, etc. PLLs are actively used in radio physics both in analog and digital versions. One of the promising directions for collective PLLs development is the study of ensembles of neuromorphic networks based on PLL. Aim. To obtain wave analogues characterizing the collective PLL not as a discrete network, but as a continuous (distributed) media. Materials and methods. An unidirectional model (without mutual control circuits) of the cascade structure of the PLL. Results. Wave analogues of cascade-coupled phase synchronization systems that do not contain mutual control circuits were found. A solution of equations of wave analogues was found. A proof of validity of the obtained approximate solution in comparison with the exact one was presented. Conclusion. It was shown that by selecting a filter in a control circuit of each single-circuit circuit with different transmission coefficients, it is possible to obtain various types of continuous media or wave analogues of chain structures based on phase synchronization systems.

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10

Bhattacharya, Madhumita, Anuj Kumar Saw, and Taraprasad Chattopadhyay. "Optical Comb Generation for DWDM Applications using Multiple Optoelectronic Phase Locked Loops." IETE Journal of Research 50, no. 5 (September 2004): 331–35. http://dx.doi.org/10.1080/03772063.2004.11665522.

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11

Wang, Xinyue, and Ziyu Wang. "Spectrum conversion phase-locked loops used for 43 Gbit/s 3R optical receivers." Microwave and Optical Technology Letters 49, no. 12 (2007): 3017–20. http://dx.doi.org/10.1002/mop.22951.

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12

Goh, P., and J. E. Schutt-Ainé. "The latency insertion method for simulations of phase-locked loops." Journal of Computational Electronics 13, no. 2 (February 25, 2014): 529–36. http://dx.doi.org/10.1007/s10825-014-0564-1.

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13

Zhang, Zhao. "CMOS analog and mixed-signal phase-locked loops: An overview." Journal of Semiconductors 41, no. 11 (November 2020): 111402. http://dx.doi.org/10.1088/1674-4926/41/11/111402.

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14

Zhang Chaochao, 张超超, 王建波 Wang Jianbo, 殷聪 Yin Cong, 张宝武 Zhang Baowu, 刘若男 Liu Ruonan, 席路 Xi Lu, and 李孟瑶 Li Mengyao. "光学锁相环的研究进展." Infrared and Laser Engineering 51, no. 4 (2022): 20210156. http://dx.doi.org/10.3788/irla20210156.

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15

Simsek, Arda, Shamsul Arafin, Seong-Kyun Kim, Gordon B. Morrison, Leif A. Johansson, Milan L. Mashanovitch, Larry A. Coldren, and Mark J. W. Rodwell. "Evolution of Chip-Scale Heterodyne Optical Phase-Locked Loops Toward Watt Level Power Consumption." Journal of Lightwave Technology 36, no. 2 (January 15, 2018): 258–64. http://dx.doi.org/10.1109/jlt.2017.2758744.

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16

Kazovsky, L. G., and B. Jensen. "Experimental relative frequency stabilization of a set of lasers using optical phase-locked loops." IEEE Photonics Technology Letters 2, no. 7 (July 1990): 516–18. http://dx.doi.org/10.1109/68.56643.

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17

Olkiewicz, R., and M. Żaba. "Dynamics of a self-phase-locked nondegenerate optical parametric oscillator with nonsymmetric feedback loops." Journal of Physics B: Atomic, Molecular and Optical Physics 42, no. 20 (October 7, 2009): 205504. http://dx.doi.org/10.1088/0953-4075/42/20/205504.

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18

Ramesh, Jayabalan, Ponnusamy Thangapandian Vanathi, and Kandasamy Gunavathi. "Fault Classification in Phase-Locked Loops Using Back Propagation Neural Networks." ETRI Journal 30, no. 4 (August 8, 2008): 546–54. http://dx.doi.org/10.4218/etrij.08.0108.0133.

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19

Grant, M., W. Michie, and M. Fletcher. "The performance of optical phase-locked loops in the presence of nonnegligible loop propagation delay." Journal of Lightwave Technology 5, no. 4 (1987): 592–97. http://dx.doi.org/10.1109/jlt.1987.1075532.

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20

PAULS, GREGORY, and T. S. KALKUR. "JITTER ANALYSIS AND PREDICTION FOR PHASE LOCKED LOOPS UTILIZING FERROELECTRIC CAPACITORS." Integrated Ferroelectrics 93, no. 1 (December 11, 2007): 10–20. http://dx.doi.org/10.1080/10584580701755468.

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21

Roncagliolo, Pedro A., Javier G. García, and Carlos H. Muravchik. "Optimized Carrier Tracking Loop Design for Real-Time High-Dynamics GNSS Receivers." International Journal of Navigation and Observation 2012 (June 3, 2012): 1–18. http://dx.doi.org/10.1155/2012/651039.

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Carrier phase estimation in real-time Global Navigation Satellite System (GNSS) receivers is usually performed by tracking loops due to their very low computational complexity. We show that a careful design of these loops allows them to operate properly in high-dynamics environments, that is, accelerations up to 40 g or more. Their phase and frequency discriminators and loop filter are derived considering the digital nature of the loop inputs. Based on these ideas, we propose a new loop structure named Unambiguous Frequency-Aided Phase-Locked Loop (UFA-PLL). In terms of tracking capacity and noise resistance UFA-PLL has the same advantages of frequently used coupled-loop schemes, but it is simpler to design and to implement. Moreover, it can keep phase lock in situations where other loops cannot. The loop design is completed selecting the correlation time and loop bandwidth that minimize the pull-out probability, without relying on typical rules of thumb. Optimal and efficient ways to smooth the phase estimates are also presented. Hence, high-quality phase measurements—usually exploited in offline and quasistatic applications—become practical for real-time and high-dynamics receivers. Experiments with fixed-point implementations of the proposed loops and actual radio signals are also shown.

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22

Zhou, Yong-Hong Ma, Qing-Xia Mu, Guo-Hui. "Enhanced continuous-variable entanglement by self-phase-locked type-II optical parameter oscillator with feedback loops." Journal of Physics B: Atomic, Molecular and Optical Physics 42, no. 12 (June 1, 2009): 129801. http://dx.doi.org/10.1088/0953-4075/42/12/129801.

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23

Kazovsky, L. "Balanced phase-locked loops for optical homodyne receivers: Performance analysis, design considerations, and laser linewidth requirements." Journal of Lightwave Technology 4, no. 2 (1986): 182–95. http://dx.doi.org/10.1109/jlt.1986.1074698.

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24

Fereidountabar, Amirhossein, Gian Carlo Cardarilli, and Marco Re. "High Dynamic Optimized Carrier Loop Improvement for Tracking Doppler Rates." Journal of Electrical and Computer Engineering 2015 (2015): 1–6. http://dx.doi.org/10.1155/2015/679505.

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Mathematical analysis and optimization of a carrier tracking loop are presented. Due to fast changing of the carrier frequency in some satellite systems, such as Low Earth Orbit (LEO) or Global Positioning System (GPS), or some planes like Unmanned Aerial Vehicles (UAVs), high dynamic tracking loops play a very important role. In this paper an optimized tracking loop consisting of a third-order Phase Locked Loop (PLL) assisted by a second-order Frequency Locked Loop (FLL) for UAVs is proposed and discussed. Based on this structure an optimal loop has been designed. The main advantages of this approach are the reduction of the computation complexity and smaller phase error. The paper shows the simulation results, comparing them with a previous work.

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25

Sánchez-Azqueta, C., J. Aguirre, C. Gimeno, C. Aldea, and S. Celma. "High-resolution wide-band LC-VCO for reliable operation in phase-locked loops." Microelectronics Reliability 63 (August 2016): 251–55. http://dx.doi.org/10.1016/j.microrel.2016.06.018.

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26

Ma, Yong-Hong, Qing-Xia Mu, Guo-Hui Yang, and Ling Zhou. "Enhanced continuous-variable entanglement by a self-phase-locked type-II optical parameter oscillator with feedback loops." Journal of Physics B: Atomic, Molecular and Optical Physics 41, no. 21 (October 13, 2008): 215502. http://dx.doi.org/10.1088/0953-4075/41/21/215502.

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27

Jin, Shilei, Longtao Xu, Peter Herczfeld, Ashish Bhardwaj, and Yifei Li. "Recent progress in attenuation counterpropagating optical phase-locked loops for high-dynamic-range radio frequency photonic links." Photonics Research 2, no. 4 (July 14, 2014): B45. http://dx.doi.org/10.1364/prj.2.000b45.

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28

Jie, Pan, Yang Haigang, and Yang Liwu. "An area-saving dual-path loop filter for low-voltage integrated phase-locked loops." Journal of Semiconductors 30, no. 10 (October 2009): 105011. http://dx.doi.org/10.1088/1674-4926/30/10/105011.

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29

Zhichao, Gong, Lu Lei, Liao Youchun, and Tang Zhangwen. "Design and noise analysis of a fully-differential charge pump for phase-locked loops." Journal of Semiconductors 30, no. 10 (October 2009): 105013. http://dx.doi.org/10.1088/1674-4926/30/10/105013.

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30

KIM, Y., K. KIM, I. KIM, and S. KANG. "A New Built-in Self Test Scheme for Phase-Locked Loops Using Internal Digital Signals." IEICE Transactions on Electronics E91-C, no. 10 (October 1, 2008): 1713–16. http://dx.doi.org/10.1093/ietele/e91-c.10.1713.

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31

Shin, C. H., and M. Ohtsu. "Improved allan variance real-time processing system to measure frequency tracking error of heterodyne optical phase-locked loops." Electronics Letters 26, no. 19 (1990): 1571. http://dx.doi.org/10.1049/el:19901008.

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32

Zhang, Li, Ajay Poddar, Ulrich Rohde, and Afshin Daryoush. "Analytical and Experimental Evaluation of SSB Phase Noise Reduction in Self-Injection Locked Oscillators Using Optical Delay Loops." IEEE Photonics Journal 5, no. 6 (December 2013): 6602217. http://dx.doi.org/10.1109/jphot.2013.2289958.

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33

Liu Qixin, 刘琪鑫, 张晔 Zhang Ye, 孙剑芳 Sun Jianfang, and 徐震 Xu Zhen. "基于光锁相环的稳频深紫外激光系统." Chinese Journal of Lasers 50, no. 7 (2023): 0701003. http://dx.doi.org/10.3788/cjl220935.

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34

Yang, Xiu, Chanchan Luo, Ben Zhang, Bocang Qiu, and Ruiying Zhang. "Simulation and Design of a PIC-Based Heterodyne Optical Phase Locked Loop." Photonics 10, no. 3 (March 21, 2023): 336. http://dx.doi.org/10.3390/photonics10030336.

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In this paper, we report on our simulation and design of a photonic integrated circuits (PIC)-based heterodyne optical phase-locked loop (OPLL). Our simulation reveals that the OPLL operation can be in one of three states, i.e., absolutely stable, metastable, and unstable states, depending on the relative position of the initial phase reversal point to the loop bandwidth. By systematically optimizing all of the loop parameters involved, the loop bandwidth of 247.8 MHz and the residual phase noise variance of 0.012 rad2 are theoretically obtained in such a PIC-OPLL system, which are better than any reported counterparts. In addition, the lowest required power of the master laser is also evaluated, assuming that the largest acceptable residual phase noise variance is 0.02 rad2, and it is found that the lowest master laser power is −54 dBm in our current OPLL system, and this value can be reduced to −56 dBm, providing that the summed linewidth is reduced to 10 kHz.

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35

ZHONG, YIHUI, ZUXING ZHANG, and XIANYANG TAO. "PASSIVELY MODE-LOCKED FIBER LASER USING SOA-BASED NONLINEAR OPTICAL LOOP MIRROR." Journal of Nonlinear Optical Physics & Materials 21, no. 02 (June 2012): 1250027. http://dx.doi.org/10.1142/s0218863512500270.

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We have demonstrated numerically a passively mode-locked fiber laser based on nonlinear optical loop mirror with a semiconductor optical amplifier (SOA). Its operation principle is based on the creation of nonlinear phase shift difference between the counter propagating beams through the use of SOA and a half-wavelength plate (HWP) in the loop. This is a novel passively mode-locked fiber laser based on SOA.

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36

Matrosov, V. V., and M. V. Shalfeeva. "Influence of coupling parameters on the nonlinear dynamics of two cascade-coupled phase-locked loops." Radiophysics and Quantum Electronics 38, no. 3-4 (1996): 180–82. http://dx.doi.org/10.1007/bf01037895.

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37

Sun, Nan, William F. Andress, Kyoung-Ho Woo, and Don-Hee Ham. "Surpassing Tradeoffs by Separation: Examples in Transmission Line Resonators, Phase-Locked Loops, and Analog-to-Digital Converters." JSTS:Journal of Semiconductor Technology and Science 8, no. 3 (September 30, 2008): 210–20. http://dx.doi.org/10.5573/jsts.2008.8.3.210.

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38

Ganotra, Dinesh, Joby Joseph, and Kehar Singh. "Second- and first-order phase-locked loops in fringe profilometry and application of neural networks for phase-to-depth conversion." Optics Communications 217, no. 1-6 (March 2003): 85–96. http://dx.doi.org/10.1016/s0030-4018(02)02362-3.

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39

Zhou, Yan, and Claire Gu. "The methods of RF phase locked loops for active mode-locking picosecond laser with different repetition rates." Microwave and Optical Technology Letters 51, no. 12 (September 23, 2009): 2886–92. http://dx.doi.org/10.1002/mop.24803.

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40

Asghar, Haroon, and John G. McInerney. "Control of Timing Stability, and Suppression in Delayed Feedback Induced Frequency-Fluctuations by Means of Power Split Ratio and Delay Phase-Dependent Dual-Loop Optical Feedback." Applied Sciences 11, no. 10 (May 16, 2021): 4529. http://dx.doi.org/10.3390/app11104529.

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We experimentally demonstrated a power split ratio and optical delay phase dependent dual-loop optical feedback to investigate the suppression of frequency-fluctuations induced due to delayed optical feedback. The device under investigation is self-mode-locked (SML) two-section quantum-dash (QDash) laser operating at ∼21 GHz and emitting at ∼1.55 μm. The effect of two selective combinations of power split ratios (Loop-I: −23.29 dB and Loop-II: −28.06 dB, and Loop-I and Loop-II: −22 dB) and two optical delay phase settings ((i) stronger cavity set to integer resonance and fine-tuning the weaker cavity, (ii) weaker cavity set to integer resonance and fine-tuning of stronger cavity) on the suppression of cavity side-bands have been studied. Measured experimental results demonstrate that delayed optical feedback induced frequency-fluctuations can be effectively suppressed on integer resonance as well as on full delay range tuning (0–84 ps) by adjusting coupling strength −22 dB through Loop-I and Loop-II, respectively. Our findings suggest that power split ratio and delays phase-dependent dual-loop optical feedback can be used to maximize the performance of semiconductor mode-locked lasers.

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41

Kassa, Wosen-Eshetu, Anne-Laure Billabert, Salim Faci, and Catherine Algani. "Simulation of heterodyne RoF systems based on 2 DFB lasers: application to an optical phase-locked loop design." International Journal of Microwave and Wireless Technologies 6, no. 2 (February 19, 2014): 207–11. http://dx.doi.org/10.1017/s1759078714000117.

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This paper presents a simulation approach of optical heterodyne systems by using the equivalent circuit representation of a distributed feedback laser (DFB) in the electrical domain. Since the electrical representation of the DFB laser is developed from the rate equations, its characteristics such as non-linearity, relative intensity noise (RIN), and phase noise can be predicted precisely for various biasing conditions. The model is integrated in a heterodyne radio over fiber (RoF) system where two DFB lasers are used to generate a millimeter-wave (mm-wave) signal. An optical phase-locked loop is also introduced to reduce the phase noise on the mm-wave signal. The optical phase noise contribution of individual lasers to the mm-wave signal is evaluated and compared with theoretical results. It is shown that the phase noise of the mm-wave is reduced considerably depending on the loop bandwidth and propagation delay. With the circuit simulation approach proposed, optical and mm-wave phase noises can be studied together with other circuit environments such as parasitic effects and driver circuits.

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42

Alrebdi, Tahani A., Mamoon Asghar, and Haroon Asghar. "All Optical Stabilizations of Nano-Structure-Based QDash Semiconductor Mode-Locked Lasers Based on Asymmetric Dual-Loop Optical Feedback Configurations." Photonics 9, no. 6 (May 26, 2022): 376. http://dx.doi.org/10.3390/photonics9060376.

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We report feedback-induced frequency oscillations using a power-split-ratio through asymmetric dual-loop optical feedback (Loop I: ~2.2 km and Loop II: ~20 m) subject to a self-mode-locked two-section QDash laser emitting at 1550 nm and operating at 21 GHz repetition rate. To assess the suppression of frequency resonances, three chosen combinations of feedback power (Loop I: −27.27 dB and Loop II: −19.74 dB, Loop I: −22 dB and Loop II: −22 dB, and Loop I: −19.74 dB and Loop II: −27.27 dB) through asymmetric dual-loop optical feedback have been studied. Based on the chosen coupling strength, an optimum feedback ratio that yields better side-mode suppression has been identified. Our results demonstrate that side-mode suppression can be achieved by the fine adjustment of coupling power through either cavity of dual-loop feedback configurations. Furthermore, we have further demonstrated that frequency fluctuations from the RF spectra can be filtered by carefully selecting the delay phase of the second cavity. Our experimental findings suggest that semiconductor mode-locked lasers based on dual-loop feedback configurations can be used to develop noise oscillations free from integrated photonic oscillators for potential applications in telecommunications, multiplexing, and frequency-comb generation.

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43

Zhang, Xiang, Yong Shen, Xiaokang Tang, Qu Liu, and Hongxin Zou. "Inverse Saturable Absorption Mechanism in Mode-Locked Fiber Lasers with a Nonlinear Amplifying Loop Mirror." Photonics 10, no. 3 (March 1, 2023): 261. http://dx.doi.org/10.3390/photonics10030261.

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From the perspective of the differential phase delay experienced by the two counterpropagating optical fields, the self-starting of the mode-locked fiber laser with a non-linear amplifying loop mirror (NALM) is theoretically studied. Although it is generally believed that NALM shows a saturable absorption effect on both continuous wave (CW) light and pulses, we find a counter-intuitive fact that cross-phase modulation (XPM) leads to opposite signs of differential non-linear phase shifts (NPSs) in these two cases, resulting in inverse saturable absorption (ISA) during the pulse formation process. The ISA is not helpful for the self-starting of laser mode-locking and can be alleviated by introducing a non-reciprocal phase shifter into the fiber loop. These results are helpful for optimizing the design of NALM and lowering the self-starting threshold of the high-repetition-rate mode-locked fiber laser.

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44

Oon, F. E., and Rainer Dumke. "Compact single-seed, module-based laser system on a transportable high-precision atomic gravimeter." AVS Quantum Science 4, no. 4 (December 2022): 044401. http://dx.doi.org/10.1116/5.0119151.

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A single-seed, module-based compact laser system is demonstrated on a transportable [Formula: see text]-based high-precision atomic gravimeter. All the required laser frequencies for the atom interferometry are provided by free-space acousto-optic modulators (AOMs) and resonant electro-optic phase modulators (EOMs). The optical phase-locked loop between the two optical paths derived from the same laser provides an easy frequency manipulation between two laser frequencies separated by the hyperfine frequency of 6.835 GHz using an AOM and an EOM, respectively. Our scheme avoids parasite Raman transitions present in the direct EOM modulation scheme (modulating directly at the frequency of the hyperfine splitting), which have detrimental effects on the accuracy of the gravity measurements. The optical phase-locked loop also provides a convenient way for vibration compensation through the Raman lasers' phase offset. Furthermore, the modular design approach allows plug-and-play nature on each individual optic module and also increases the mechanical stability of the optical systems. We demonstrate high-precision gravity measurements with 17.8 [Formula: see text] stability over 250 s averaging time and 2.5 [Formula: see text] stability over 2 h averaging time.

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45

Cortés, Iñigo, Johannes Rossouw van der Merwe, Jari Nurmi, Alexander Rügamer, and Wolfgang Felber. "Evaluation of Adaptive Loop-Bandwidth Tracking Techniques in GNSS Receivers." Sensors 21, no. 2 (January 12, 2021): 502. http://dx.doi.org/10.3390/s21020502.

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Global navigation satellite system (GNSS) receivers use tracking loops to lock onto GNSS signals. Fixed loop settings limit the tracking performance against noise, receiver dynamics, and the current scenario. Adaptive tracking loops adjust these settings to achieve optimal performance for a given scenario. This paper evaluates the performance and complexity of state-of-the-art adaptive scalar tracking techniques used in modern digital GNSS receivers. Ideally, a tracking channel should be adjusted to both noisy and dynamic environments for optimal performance, defined by tracking precision and loop robustness. The difference between the average tracking jitter of the discriminator’s output and the square-root Cramér-Rao bound (CRB) indicates the loops’ tracking capability. The ability to maintain lock characterizes the robustness in highly dynamic scenarios. From a system perspective, the average lock indicator is chosen as a metric to measure the performance in terms of precision, whereas the average number of visible satellites being tracked indicates the system’s robustness against dynamics. The average of these metrics’ product at different noise levels leads to a reliable system performance metric. Adaptive tracking techniques, such as the fast adaptive bandwidth (FAB), the fuzzy logic (FL), and the loop-bandwidth control algorithm (LBCA), facilitate a trade-off for optimal performance. These adaptive tracking techniques are implemented in an open software interface GNSS hardware receiver. All three methods steer a third-order adaptive phase locked loop (PLL) and are tested in simulated scenarios emulating static and high-dynamic vehicular conditions. The measured tracking performance, system performance, and time complexity of each algorithm present a detailed analysis of the adaptive techniques. The results show that the LBCA with a piece-wise linear approximation is above the other adaptive loop-bandwidth tracking techniques while preserving the best performance and lowest time complexity. This technique achieves superior static and dynamic system performance being 1.5 times more complex than the traditional tracking loop.

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46

Reddy, Gujjula Ramana, Chitra Perumal, Prakash Kodali, and Bodapati Venkata Rajanna. "Design and memory optimization of hybrid gate diffusion input numerical controlled oscillator." International Journal of Reconfigurable and Embedded Systems (IJRES) 12, no. 1 (March 1, 2023): 78. http://dx.doi.org/10.11591/ijres.v12.i1.pp78-86.

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The numerically controlled oscillator (NCO) is one of the digital oscillator signal generators. It can generate the clocked, synchronous, discrete waveform, and generally sinusoidal. Often NCOs care utilized in the combinations of digital to analog converter (DAC) at the outputs for creating direct digital synthesizer (DDS). The network on chips (NOCs) are utilized in various communication systems that are fully digital or mixed signals such as synthesis of arbitrary wave, precise control for sonar systems or phased array radar, digital down/up converters, all the digital phase locked loops (PLLs) for cellular and personal communication system (PCS) base stations and drivers for acoustic or optical transmissions and multilevel phase shift keying/frequency shift keying (PSK/FSK) modulators or demodulators (modem). The basic architecture of NCO will be enhanced and improved with less hardware for facilitating complete system level support to various sorts of modulation with minimum FPGA resources. In this paper design and memory optimization of hybrid gate diffusion input (GDI) numerically controlled oscillator based on field programmable gate array (FPGA) is implemented. compared with NCO based 8-bit microchip, memory optimization of hybrid GDI numerically controlled oscillator based on FPGA gives effective outcome in terms of delay, metal-oxide-semiconductor field-effect transistors (MOSFET’s) and nodes.

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47

Brendel, Friederike, Thomas Zwick, Julien Poëtte, and Béatrice Cabon. "Sideband stabilization in the presence of LO phase noise: analysis and system demonstrator." International Journal of Microwave and Wireless Technologies 6, no. 2 (December 6, 2013): 129–37. http://dx.doi.org/10.1017/s1759078713001025.

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We present a technique allowing the stabilization and tuning of a modulation sideband in the presence of high-carrier frequency jitter and increased carrier phase noise. This technique is of particular interest in communication systems where oscillators providing the carrier signal cannot be stabilized by a conventional phase-locked loop, such as systems relying on low-cost optical LO generation techniques. The results obtained in simulation are validated by measurements carried out on a modular system demonstrator.

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48

Zhang, Xiang, Xue Deng, Qi Zang, Dongdong Jiao, Jing Gao, Dan Wang, Qian Zhou, et al. "Coherent Optical Frequency Transfer via a 490 km Noisy Fiber Link." Chinese Physics Letters 39, no. 4 (April 1, 2022): 044201. http://dx.doi.org/10.1088/0256-307x/39/4/044201.

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We demonstrate the coherent transfer of an ultrastable optical frequency reference over a 490 km noisy field fiber link. The fiber-induced phase noise power spectrum density per-unit-length at 1 Hz offset frequency can reach up to 510 rad2⋅Hz−1⋅km−1, which is much higher than the fiber noise observed in previous reports. This extreme level of phase noise is mainly due to the fiber link laying underground along the highway. Appropriate phase-locked loop parameters are chosen to complete the active compensation of fiber noise by measuring the intensity fluctuation of additional phase noise and designing a homemade digital frequency division phase discriminator with a large phase detection range of 212 π rad. Finally, a noise suppression intensity of approximately 40 dB at 1 Hz is obtained, with fractional frequency instability of 1.1 × 10−14 at 1 s averaging time, and 3.7 × 10−19 at 10000 s. The transfer system will be used for remote atomic clock comparisons and optical frequency distribution over a long-distance communication network established in China.

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Zhao, Yang, Shaokai Wang, Wei Zhuang, and Tianchu Li. "Raman-Laser System for Absolute Gravimeter Based On 87Rb Atom Interferometer." Photonics 7, no. 2 (May 15, 2020): 32. http://dx.doi.org/10.3390/photonics7020032.

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The paper describes a Raman-laser system with high performance for an absolute gravimeter that was based on 87Rb atom interferometer. As our gravimeter is a part of the standard acceleration of gravity of China, the Raman lasers’ characteristics should be considered. This laser system includes two diode lasers. The master laser is frequency locked through the frequency-modulation (FM) spectroscopy technology. Its maximum frequency drift is better than 50 kHz in 11 h, which is measured by home-made optical frequency comb. The slave laser is phase locked to the master laser with a frequency difference of 6.8346 GHz while using an optical phase lock loop (OPLL). The phase noise is lower than −105 dBc/Hz at the Fourier frequency from 200 Hz to 42 kHz. It is limited by the measurement sensitivity of the signal source analyzer in low Fourier frequency. Furthermore, the power fluctuation of Raman lasers’ pulses is also suppressed by a fast power servo system. While using this servo system, Raman lasers’ pulses could be fast re-locked while its fast turning on again in the pulse sequence. The peak value fluctuation of the laser power pulses is decreased from 25% to 0.7%, which is improved over 35 times. This Raman-laser system can stably operate over 500 h, which is suited for long-term highly precise and accurate gravity measurements.

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50

Gholami-Khesht, Hosein, Pooya Davari, Chao Wu, and Frede Blaabjerg. "A Systematic Control Design Method with Active Damping Control in Voltage Source Converters." Applied Sciences 12, no. 17 (September 5, 2022): 8893. http://dx.doi.org/10.3390/app12178893.

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This paper proposes a systematic control design method for active damping control of grid-connected voltage source converters (VSCs). The proposed control method considers the conventional cascaded control loops and improves them by including additional states feedback-based active damping. In such a way, all control gains are lumped into one control gain matrix based on the proposed formulation. The lumping of all control gains into one matrix leads to a linear optimization problem, so different techniques can be used to calculate control gains. This work calculates them by using a simple but effective optimal control theorem as a noteworthy feature. The proposed control method can overcome the challenges of designing multiple control loops, evaluating wide time scale dynamics, and tuning required control parameters. Moreover, direct relationships between the proposed tuning parameters and system well-known stability and performance indicators such as maximum damping factor, minimum damping ratio, and the control efforts are identified, providing good physical insight. Finally, the proposed control structure and optimal gain calculations ensure power converter robustness against uncertainties in the grid’s short-circuit ratio (SCR) and different operating-point conditions. When the grid’s SCR changes from 10 (strong grid condition) to 1 (ultra-weak grid condition), the system under the proposed control method maintains good stability margins and simultaneously provides a fast dynamic response by facilitating the implementation of a high-bandwidth phase-locked loop (PLL). The performance of the proposed control strategy was investigated analytically and practically by conducting eigenvalue analysis, simulations, and experiments.

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