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Journal articles on the topic 'Continuous transmission frequency modulation'

Author: Grafiati

Published: 4 June 2021

Last updated: 1 February 2022

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1

Campo-Valera, María, and Ivan Felis. "Underwater Acoustic Communication for The Marine Environment’s Monitoring." Proceedings 42, no. 1 (2019): 51. http://dx.doi.org/10.3390/ecsa-6-06642.

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Within the possibilities of non-linear acoustics, the parametric effect offers a range of acoustic applications that are currently being exploited in different areas. In underwater acoustics, environmental monitoring and security are one of the applications that can benefit from these technologies, allowing the transmission of information in a directivity controlled and efficient manner. An essential aspect for the optimal functioning of these technologies is the choice of the modulation that best suits the needs of communication. In the present work, different modulation techniques are explained, through their non-linear propagation, that allows generating the signals to be propagated. Among the modulations presented in this work, we have Amplitude Modulation (AM), Continuous Phase Frequency Shift Keying (CPFSK), and Linear Frequency Modulation (LFM) modulations normally used in communications. These modulations are performed with a modulating signal (sine and sine-sweeps type) whose non-linear demodulation determines the shape of the 1 and 0 bits, through the transmission of a bit string. With all this, comparisons are made between each technique, to obtain a more precise detection and discrimination of the bits.

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2

Wang, Yang, and Jun Yang. "Continuous Transmission Frequency Modulation Detection under Variable Sonar-Target Speed Conditions." Sensors 13, no. 3 (2013): 3549–67. http://dx.doi.org/10.3390/s130303549.

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3

Suhadolnik, Nejc, Jernej Rozman, Tilen Svete, Žiga Korošak, Maja Atanasijević-Kunc, and Anton Pleteršek. "Phase Detection and Modulation Improvement for Active Load Modulation during Continuous Transmission." Sensors 21, no. 18 (2021): 6155. http://dx.doi.org/10.3390/s21186155.

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The paper covers one of the communication technologies used in wireless sensor networks. We have presented improvements in existing radio frequency identification (RFID) systems to address the problem of the phase selection in active load modulation (ALM). The phase selection affects the interoperability of communication devices and has to be addressed in the design phase of a new tag. A novel transmission method is presented to make the phase selection irrelevant for device interoperability. A second solution is shown to improve the existing system synchronization, which allows operation with arbitrary selected phase. A mathematical analysis of signals present on the antenna was used together with the reference reader model to perform an analysis of proposed improvements. We proved that the proposed transmission method is less affected by phase selection. Furthermore, we demonstrated that existing system improvement allows synchronization and operation at an arbitrarily selected phase despite the continuous transmission and large signal-to-interference ratio.

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M. Alatwi, Aadel, and Ahmed Nabih Zaki Rashed. "Hybrid CPFSK/OQPSK modulation transmission techniques’ performance efficiency with RZ line coding–based fiber systems in passive optical networks." Indonesian Journal of Electrical Engineering and Computer Science 21, no. 1 (2021): 263. http://dx.doi.org/10.11591/ijeecs.v21.i1.pp263-270.

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<p><span>This study shows hybrid continuous-phase frequency shift keying (CPFSK)/optical quadrature-phase shift keying (OQPSK) modulation transmission techniques’ performance efficiency with return-to-zero (RZ) line coding scheme–based fiber systems in passive optical networks. Max. Q factor/min. bit error rate variations versus modulation frequency and fiber length are studied in detail for various bits/symbol, based on hybrid proposed modulation transmission techniques. Also, optical power and received electrical power variations are simulated with fiber-length variations at a specified modulation frequency of 300 GHz. Max. Q Factor, min. BER, max. signal power, and min. noise power variations are based on hybrid modulation techniques for CPFSK/OQPSK of 32 bits/symbol and a modulation frequency of 500 GHz through a fiber length of 30 km.</span></p>

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Banket, Victor, and Sergei Manakov. "INCREASING THE SPECIFIC RATE OF CONTINUOUS PHASE MODULATION SIGNALS." Informatyka Automatyka Pomiary w Gospodarce i Ochronie Środowiska 9, no. 1 (2019): 57–60. http://dx.doi.org/10.5604/01.3001.0013.0927.

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A method has been developed for increasing the specific rate of frequency modulation signals with a continuous phase based on the use of the properties of composite Walsh-Barker sequences. The proposed method is applicable for multi-position signals. Simultaneously, the tasks of synchronization and registration of processing results are solved. The increase in the efficiency of digital signal transmission systems is theoretically justified.

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Hao, Zi Qiang, Hong Zuo Li, and Xin Ren. "Research on L-PPM Modulation Rate of Pulse Fiber Lasers." Advanced Materials Research 926-930 (May 2014): 1787–90. http://dx.doi.org/10.4028/www.scientific.net/amr.926-930.1787.

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Compared with continuous laser, pulsed fiber laser has the advantages of high peak power, which is widely used in device processing, military defense and other areas. As the repetition frequency of pulsed fiber laser is low and therefore it cannot realize high rate transmission, this paper does the research on L-PPM modulation of pulsed fiber laser to find a method of effectively improving the modulation rate of pulsed fiber laser. Experimental results show that the L-PPM modulation can improve the transmission rate of the pulsed fiber laser whose repetition frequency is 200K to 1.387Mbps. The research results are useful for the application of pulsed fiber laser in communication.

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7

Remlein, Piotr. "Multiuser cpm transmission for mimo systems." Image Processing & Communications 18, no. 4 (2013): 59–65. http://dx.doi.org/10.2478/v10248-012-0093-0.

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Abstract Frequency-Division Multiplexed Continuous Phase Modulation (FDM-CPM) systems with Multiple Input Multiple Output (MIMO) transmission are investigated. In this paper, a multiuser reception scheme for CPM MIMO transmission is presented. The analyzed system is designed to achieve high spectral efficiency by exploiting the multiplexing gain of MIMO techniques. To take advantage of the multiplexing gain of MIMO systems, a Zero Forcing (ZF) MIMO detector and a low-complexity iterative algorithm for Inter- Carrier Interference (ICI) cancellation are considered. Numerical simulations have been performed to assess the performance improvement achieved with the proposed frequency-division multiplexed CPM multiuser MIMO system

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Weikert, O., and U. Zölzer. "A wireless MIMO CPM system with blind signal separation for incoherent demodulation." Advances in Radio Science 6 (May 26, 2008): 101–5. http://dx.doi.org/10.5194/ars-6-101-2008.

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Abstract. A multiple-input multiple-output (MIMO) wireless transmission system with continuous phase modulation (CPM) is considered. A novel MIMO CPM receiver with incoherent modulation is presented. The incoherent demodulation of CPM allows an uncomplicated handling of a frequency offset compared to coherent approaches requiring exact knowledge of the carrier frequency. Blind signal separation (BSS) is applied in the proposed MIMO CPM receiver to separate the signals without any knowledge of the MIMO channel. The BSS permits the demodulation of each separated signal by an incoherent CPM demodulator. For bandwidth efficient transmission partial response CPM and non-binary modulation is applied. The applicability of the proposed system is verified by simulation results.

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Pan, Xiaojie, Maosen Fan, Wenchao Zhang, Liwei Zhang, and Xing Chen. "Research on optimization method of primary frequency modulation capability based on different ratios of hydropower." E3S Web of Conferences 185 (2020): 01031. http://dx.doi.org/10.1051/e3sconf/202018501031.

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With the continuous development of China’s cross-regional interconnected power grid, large- capacity and long-distance transmission have become an important feature of China’s power grid. As the transmission capacity of single-return transmission lines continues to increase, the risk of frequency fluctuations increases, making grid operation scheduling more concerned with the performance of the unit’s primary frequency modulation. This paper tests the frequency stability of a power system under different scenarios, in which the proportion of water and thermal power in the system is different. The results represent that a system with a large proportion of hydropower has poorer frequency stability. This paper offers a method of primary frequency modulation, which proposed to improve the frequency stability of the system by increasing the time delay of the hydropower unit’s governor. The results of simulation prove that this method is an available solution to solve the problem of poor system frequency stability when a system has a high ratio of hydropower.

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Singh, Surinder, Mark Crispo, Jean-François Bousquet, and Shadi Aljendi. "A Janus compatible software-defined underwater acoustic multiple-input multiple-output modem." International Journal of Distributed Sensor Networks 17, no. 4 (2021): 155014772110106. http://dx.doi.org/10.1177/15501477211010663.

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This article describes the implementation of a multiple-input multiple-output acoustic communication link in shallow water conditions to enable a software-defined acoustic modem with a maximum transmission rate of 20 kbps in a 5-kHz bandwidth. The reliability improvement of a low-complexity Alamouti space–time block code is evaluated to improve the diversity in a high-rate transmission mode using single carrier modulation, as well as in a low-rate transmission mode relying on continuous-phase frequency-shift keying. Using measurements in realistic subsea conditions, the effect of the spatial channel correlation is demonstrated. It is found that for the space–time block code/continuous-phase frequency-shift keying, the spatial diversity is significantly degraded due to the high spatial correlation. In contrast, for the high-mode transmission rate, space–time block code with single carrier modulation offers a bit error rate improvement by a factor over hundred, in comparison to a single transmit element, demonstrating that the multiple-input multiple-output optimal code depends on the software-defined acoustic modem transmission mode.

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Qi, Junwei, Sergey B. Makarov, Mingxin Liu, Beiming Li, and Wei Xue. "Research on an Optimization Method for a Partially Responsive Continuous Phase Modulated (CPM) Signal Based on an Optimal Generic Function." Symmetry 11, no. 9 (2019): 1114. http://dx.doi.org/10.3390/sym11091114.

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This paper establishes an optimal generic function model in order to obtain a continuous phase modulated (CPM) signal with a smoother phase modulation function. This is achieved by finding the solution to the symbol signals at different lengths of the CPM function. In the solution process, the unknown amount that needs to be solved is reduced by using the even function symmetry characteristic of the signal to be solved. For each different form of the signal, the time domain form of the CPM function and the corresponding normalized energy spectral density are compared under the influence of the phase modulation signal length and the generic function parameter n. The data transmission rate is improved by introducing inter-symbol interference, and the modulation process is realized using six-way parallel transmission when the CPM function is 6T. The simulation results show that the CPM function obtained by establishing an optimal generic function model has high-quality time-frequency characteristics. The real-time phase trajectory and the high-order derivative are both continuous, and the modulated signal has constant envelope characteristics. The CPM function has a fast rolling-off in the frequency domain and small out-of-band radiation, which greatly improves the characteristics of the frequency band utilization.

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12

Kumar, Dheeraj. "Transmission of BPSK in UWB using MATLAB." International Journal for Research in Applied Science and Engineering Technology 9, no. VI (2021): 984–90. http://dx.doi.org/10.22214/ijraset.2021.35106.

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Ultra Wide Band (UWB) is a promising technology for sensor networks, broadband wireless data accessing, positioning and location finding applications. This project outlines the development and validation of a single transmitter and receiver system across the multipath channel. We have designed and tested a UWB simulator using MATLAB to operate for a continuous wave. After a brief survey BPSK was chosen to be the modulation technique. This paper outlines the basic design and simulation of a BPSK signal through the UWB. The system parameters and the simulation runs are shown and described along with the BER calculations. The time domain and frequency domain study is shown and analyzed of a IR-UWB channel with the transmitter, channel and the receiver blocks. This model compares and analyses the bit efficiency of a channel, for a BPSK modulation technique for various bit powers. The example simulation uses rudimental inputs to visualize the response of the channel.

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13

Li, Zhong Wei, and Rui He Wang. "Comparative Analysis on OQPSK and QDPSK of Continuous Pressure Wave System in Drilling Fluid Channel." Applied Mechanics and Materials 130-134 (October 2011): 3607–15. http://dx.doi.org/10.4028/www.scientific.net/amm.130-134.3607.

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Based on the urgent needs for high transmission speed and high reliability of wireless MWD, the OQPSK modulation of the drilling fluid continuous wave signal is proposed in this article. The Principle of delay orthogonal modulation and coherent demodulation of OQPSK are studied, and the changes in the phase vector of the inputted bit sequence are analyzed; according to the principle of continuous wave generation, the phase adjustment mechanism of rotary value are analyzed and the relationship between the signal waveform, as well as the rotational speed when adjusting the phase, is studied; the information transmission rate, band efficiency and bit error rate of the OQPSK and QDPSK continuous wave communication systems are comparatively analyzed and simulated. The results show that OQPSK eliminates the phase transition of π, which belongs to constant envelope modulation, is suitable for the transmission under low SNR drilling fluid channel, meanwhile simplifies the phase adjustment and reduces generator design. QDPSK can simplify the computational complexity of phase adjustment, and reduces the design difficulty of the continuous-wave generator’s control circuit. The rotary valve forms of "slow down - speed up" and " speed up - slow down " are suitable for π / 2 and 3π / 2 phase jump respectively; the motor control modes which combine closed loop position and closed loop velocity can achieve phase stable signal and reduce the dynamic torque of the motor; in the same carrier frequency and SNR, the information rate and bandwidth efficiency of both OQPSK’s and QDPSK’s are twice as those of the two-phase shift keying system’s, and they can improve the wireless transmission performance of MWD system.

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14

Collier, Robert D., Roderick C. MacNeil, and Leslie Kay. "Performance of a continuous transmission frequency modulation (CTFM) in‐air ultrasonic system applied to dynamic production processes." Journal of the Acoustical Society of America 84, S1 (1988): S30. http://dx.doi.org/10.1121/1.2026259.

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15

A. Eid, Mahmoud M., Ashraf S. Seliem, Ahmed Nabih Zaki Rashed, Abd El-Naser A. Mohammed, Mohamed Yassin Ali, and Shaimaa S. Abaza. "High modulated soliton power propagation interaction with optical fiber and optical wireless communication channels." Indonesian Journal of Electrical Engineering and Computer Science 21, no. 3 (2021): 1575. http://dx.doi.org/10.11591/ijeecs.v21.i3.pp1575-1583.

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<p><span id="docs-internal-guid-52da184f-7fff-738a-f0e7-e8dd779e097b"><span>This paper has presented high modulated soliton power transmission interaction with optical fiber and optical wireless communication channels at flow rate of 40 Gbps and 20 km link range. The proposed modulation schemes are continuous phase frequency shift keying (CPFSK), Quadrature amplitude modulation (QAM), differential phase shift keying (DPSK), frequency shift keying (FSK), pulse amplitude modulation (PAM), minimum shift keying (MSK), and optical quadrature phase shift keying (OQPSK). CPFSK has presented better performance than other proposed modulation schemes for both optical fiber and optical wireless communication channels. The enhancement of optical signal/noise ratio at fiber/wireless channel, received electrical power and signal/noise ratio at optical receiver with increase of bits per symbol for different proposed modulation schemes except for CPFSK scheme. Therefore it is evident that CPFSK modulation scheme is more efficient and better performance than other modulation schemes for different communication channels. The obtained results are simulated with optisystem program version 13. </span></span></p>

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IIJIMA, YASUYUKI, SHIGEYUKI INOUE, TOMOKO KASHIMA, ATSUSHI FUKASAWA, and YUMI TAKIZAWA. "COHERENT SS DEMODULATION WITH ESTIMATION AND COMPENSATION OF PHASE ROTATION USING A PILOT CHANNEL." Journal of Circuits, Systems and Computers 13, no. 02 (2004): 361–73. http://dx.doi.org/10.1142/s0218126604001350.

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This paper describes and clarifies a configuration and its performance of estimation and compensation of phase rotation in radio propagation using a pilot channel for the SS (spread spectrum) modulation and demodulation. Coherent radio transmission scheme is composed as follows: (i) Continuous pilot signal is transmitted through a pilot channel, (ii) the pilot channel is composed of O-QPSK and QPSK for reverse and forward links, respectively, (iii) pilot signal is added in each I channel of O-QPSK and QPSK, and (iv) coherent demodulation is achieved by estimation and compensation of phase rotation using the pilot channel. Phase rotation and its linearity has been estimated for QPSK and O-QPSK data modulation methods. The constellation on the complex plane is used for the evaluation of phase rotation and the Eye pattern for the demodulated waveforms. The bit-error-rate (BER) versus Eb/N0 is used for the characteristics of data modulation/demodulation and SS modulation/demodulation of the proposed radio system. A proposed scheme proved that (i) estimation of rapid phase rotation caused by multipath radio propagation with high-speed Doppler shift in frequency is well realized by the use of continuous pilot transmission (pilot channel), (ii) compensation of rapid phase rotation is well done by simplified logic operations, and (iii) high performance for high speed data transmission is realized by coherent demodulation. This system will be applied to wireless LANs with high performances and simplified configurations.

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Sun, Bin, Junfang Song, Gang Zheng, and Xiongxing Zhang. "Application Research of Frequency-Modulated Continuous-Wave Displacement Sensor Based on Zero-Crossing Phase Detecting Algorithm." International Journal of Optics 2021 (March 22, 2021): 1–9. http://dx.doi.org/10.1155/2021/6669539.

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Frequency-modulated continuous-wave (FMCW) interference, as a new technology of laser interferometry, has the advantages of length traceability, large range, high accuracy, simple structure, and optical fiber transmission. Based on the formula of FMCW laser interference displacement, a zero-crossing phase detection algorithm is proposed, which can accurately calculate the initial phase of a cosine signal in a modulation period, and it is successfully applied to the contact laser interference displacement sensor. The experimental results show that the FMCW technology based on the zero-crossing phase detection algorithm can achieve the technical specifications of the contact displacement sensor with a measurement range greater than 15 mm and the standard deviation is less than 0.01 μm. The conversion of noncontact measurement to contact measurement can realize the direct measurement of workpieces with complex surface conditions on the production line, breaking through the limitation of optical measurement and expanding the application of optical fiber interferometry.

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Turovsky, A. L., and O. V. Drobik. "PROCEDURE FOR EVALUATION OF THE SUPPORTING FREQUENCY SIGNAL OF THE SATELLITE COMMUNICATION SYSTEM IN CONTINUOUS MODE." Radio Electronics, Computer Science, Control, no. 2 (June 26, 2021): 28–38. http://dx.doi.org/10.15588/1607-3274-2021-2-3.

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Context. One of the features of satellite communication systems is the advantageous use in them during the reception of the signal in the continuous mode of phase modulation of signals intended for the transmission of useful information. The use of this type of modulation requires solving the problem of estimating the carrier frequency of the signal. And the estimation itself is reduced to the problem of estimating the frequency of the maximum in the spectrum of a fragment of a sinusoidal signal against the background of additive Gaussian noise. The article considers the process of estimating the carrier frequency of a signal by a satellite communication system in a continuous mode according to the rule of maximum likelihood. Objective. Development of a procedure for estimating the carrier frequency of a signal received by a satellite communication system in a continuous mode according to the maximum likelihood rule. Method. The procedure proposed in the work and the algorithm developed on its basis allows to estimate the carrier frequency according to the rule of maximum likelihood, taking into account the conditions of uncertainty of all signal parameters by the satellite communication system in continuous mode. The results. For the purpose of practical introduction of the specified algorithm in operating schemes of satellite communication, schemes of its hardware realization are offered in work. To illustrate the ratio of the limits of the minimum limiting variance of the carrier frequency estimate, the paper presents dependencies that allow comparing the minimum limiting variance defined by the lower Cramer-Rao boundary and the minimum limiting variance determined taking into account all signal parameters. Conclusions. Analysis of these dependences showed that in real conditions the minimum dispersion of the carrier frequency of the signal according to the rule of maximum likelihood received by the satellite communication system in continuous mode with uncertainty of all signal parameters may differ significantly from the minimum dispersion obtained by applying the lower Kramer-Rao boundary. Prospective research, development and creation of algorithms and techniques aimed at estimating the carrier frequency at the minimum limiting variance in the conditions of uncertainty of all parameters of the received signal should be aimed at the maximum approximation of the minimum limiting variance of the estimated carrier frequency to the lower Cramer-Rao boundary to estimate the carrier frequency under conditions of certainty of other signal parameters.

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Alma’aitah, Abdallah Y., and Mohammad A. Massad. "Reader–Tag Commands via Modulation Cutoff Intervals in RFID Systems." Future Internet 13, no. 9 (2021): 235. http://dx.doi.org/10.3390/fi13090235.

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Radio frequency identification (RFID) technology facilitates a myriad of applications. In such applications, an efficient reader–tag interrogation process is crucial. Nevertheless, throughout reader–tag communication, significant amounts of time and power are consumed on inescapable simultaneous tag replies (i.e., collisions) due to the lack of carrier sensing at the tags. This paper proposes the modulation cutoff intervals (MCI) process as a novel reader–tag interaction given the lack of carrier sensing constraints in passive RFID tags. MCI is facilitated through a simple digital baseband modulation termination (DBMT) circuit at the tag. DBMT detects the continuous-wave cutoff by the reader. In addition, DBMT provides different flags based on the duration of the continuous-wave cutoff. Given this capability at the tag, the reader cuts off its continuous-wave transmission for predefined intervals to indicate different commands to the interrogated tag(s). The MCI process is applied to tag interrogation (or anti-collision) and tag-counting protocols. The MCI process effect was evaluated by the two protocols under high and low tag populations. The performance of such protocols was significantly enhanced with precise synchronization within time slots with more than 50% and more than 55.6% enhancement on time and power performance of anti-collision and counting protocols, respectively. Through the MCI process, fast and power-efficient tag identification is achieved in inventory systems with low and high tag mobility; alternatively, in addition to the rapid and power efficient interaction with tags, anonymous tag counting is conducted by the proposed process.

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Bi, Hui, Hao Li, and Wei Liang. "High-Squint FMCW SAR Imaging via Wavenumber Domain Algorithm." Wireless Communications and Mobile Computing 2021 (April 2, 2021): 1–7. http://dx.doi.org/10.1155/2021/5551674.

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Nowadays, because the frequency modulation continuous-wave (FMCW) synthetic aperture radar (SAR) shows good potential in minimal transmission power and weight reduction of radar systems, it has been widely used and has become a common technique in modern short-range high-resolution earth observation. Different from the conventional pulsed mode, the stop-to-go approximation is not valid in FMCW SAR. Thus, the typical SAR imaging methods need to be modified to adapt the continuous-wave scheme in practical data processing. In this letter, a wavenumber domain algorithm (WDA) is derived and used for the FMCW SAR imaging under squint and high-squint cases. With the help of the exact scene recovery ability of the proposed WDA, we can achieve the accurate recovery of the considered scene even when using the collected high-squint data and hence obtain the well-focused high-resolution image of the considered scene. Experimental results with simulated and airborne data verify the effectiveness of the proposed method.

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21

Schmidt, Jan H. "Using Fast Frequency Hopping Technique to Improve Reliability of Underwater Communication System." Applied Sciences 10, no. 3 (2020): 1172. http://dx.doi.org/10.3390/app10031172.

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Acoustic underwater communication systems designed to work reliably in shallow coastal waters must overcome major limitations such as multipath propagation and the Doppler effect. These restrictions are the reason for the complexity of receivers being built, whose task is to decode a symbol on the basis of the received signal. Additional complications are caused by the low propagation speed of the acoustic wave in the water and the relatively narrow bandwidth. Despite the continuous development of communication systems using coherent modulations, they are still not as reliable as is desirable for reliable data transmission applications. This article presents an acoustic underwater communication system that uses one of the varieties of the spread spectrum technique i.e., the fast frequency hopping technique (FFH). This technique takes advantage of binary frequency-shift keying (BFSK) with an incoherent detection method to ensure the implementation of a system whose main priority is reliable data transmission and secondary priority is the transmission rate. The compromised choice of parameters consisted of the selection between the narrow band of the hydroacoustic transducer and the maximum number of carrier frequency hops, which results from the need to take into account the effects of the Doppler effect. In turn, the number of hops and the symbol duration were selected adequately for the occurrence of multipath propagations of an acoustic wave. In addition, this article describes experimental communication tests carried out using a laboratory model of the FFH-BFSK data transmission system in the shallow water environment of Lake Wdzydze/Poland. The test results obtained for three channels of different lengths are discussed.

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Toosi, Saman, Norhisam Misron, Tsuyoshi Hanamoto, Ishak Aris, Mohd Amran Mohd Radzi, and Hiroaki Yamada. "The Study of Operation Modes and Control Strategies of a Multidirectional MC for Battery Based System." Mathematical Problems in Engineering 2015 (2015): 1–14. http://dx.doi.org/10.1155/2015/452740.

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To enhance the performance of stand-alone battery based system and to achieve the continuous power transmission, the behavior of multidirectional matrix converter (MDMC) has been analyzed in different operation modes. A systematic method interfacing a renewable source, a storage battery, and a load is proposed for a stand-alone battery based power system (SABBPS) to utilize the MDMC as PWM converter, inverter, or PWM converter and inverter in different operation modes. In this study, the Extended Direct Duty Pulse Width Modulation (EDDPWM) technique has been applied to control the power flow path between the renewable source, load, and the battery. Corresponding to generator voltage, input frequency, and loads demands, several operating states and control strategies are possible. Therefore, the boundaries and distribution of operation modes are discussed and illustrated to improve the system performance. The mathematical equation of the EDDPWM under different operation modes has been derived to achieve the maximum voltage ratio in each mode. The theoretical and modulation concepts presented have been verified in simulation using MATLAB and experimental testing. Moreover, the THD, ripple, and power flow direction have been analyzed for output current to investigate the behavior of system in each operation mode.

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Ujan, Sahar, Neda Navidi, and Rene Jr Landry. "Hierarchical Classification Method for Radio Frequency Interference Recognition and Characterization in Satcom." Applied Sciences 10, no. 13 (2020): 4608. http://dx.doi.org/10.3390/app10134608.

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The Quality of Service (QoS) and security of Satellite Communication (Satcom) are crucial as Satcom plays a significant role in a wide range of applications, such as direct broadcast satellite, earth observation, navigation, and government/military systems. Therefore, it is necessary to ensure that transmissions are incorruptible, particularly in the presence of challenges such as Radio Frequency Interference (RFI), which is of primary concern for the efficiency of communications. The security of a wireless communication system can be improved using a robust RFI detection method, which could, in turn, lead to an effective mitigation process. This paper presents a new method to recognize received signal characteristics using a hierarchical classification in a multi-layer perceptron (MLP) neural network. The considered characteristics are signal modulation and the type of RFI. In the experiments, a real-time video stream transmitted in the direct broadcast satellite is utilized with four modulation types, namely, QPSK, 8APSK, 16APSK, and 32APSK. Moreover, it is assumed that the communication signal can be combined with one of the three significant types of interference, namely, Continuous Wave Interference (CWI), Multiple CWI (MCWI), and Chirp Interference (CI). In addition, two robust feature selection techniques have been developed to select more informative features, which leads to improving the classification precision. Furthermore, the robustness of the trained techniques is assessed to predict unknown signals at different Signal to Noise Ratios (SNRs).

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Canyelles-Pericas, Pep, Paul Haigh, Zabih Ghassemlooy, et al. "Chaos Synchronization in Visible Light Communications with Variable Delays Induced by Multipath Fading." Applied System Innovation 1, no. 4 (2018): 45. http://dx.doi.org/10.3390/asi1040045.

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Visible Light Communication (VLC) uses light-emitting diodes to provide wireless connectivity in public environments. Transmission security in this emerging channel is not trivial. Chaotic modulation techniques can provide encryption directly in the physical layer based on the random-alike evolution and strong synchronization prospect given by deterministic chaos. In secure chaotic inclusion or embedding methods, continuous-time chaos oscillator models need to be synchronized via a coupling carrier. Here we present a first numerical simulation study for the impact of the variable delays induced by line-of-sight and non-line-of-sight multipath fading in complete chaotic synchronization. More precisely, we analyze a chaotic Colpitts oscillator that is simultaneously transmitting the carrier to several mobile receivers via nine spotlights. Such induced delays depend on both the receiver position and the carrier frequency, influencing the complete synchronization required in modulation via chaotic inclusion. Correlation values for several receiver positions and carrier frequencies are presented, examining the progressive emergence of the multipath effect and its impact on chaotic synchronization. We show that, for the chaotic oscillator and coupling applied in the defined room settings, complete chaotic synchronization can be achieved and that it is robust up to the tens of MHz region.

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I. Hammadi, Yousif, and Tahreer S. Mansour. "Relationship between the voltage applied to MZM arms and the generation of optical frequency comb." International Journal of Engineering & Technology 7, no. 4.15 (2018): 405. http://dx.doi.org/10.14419/ijet.v7i4.15.23026.

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In this study, an optical frequency comb source (OFCS) based on a dual-drive Mach–Zehnder modulator (MZM) is constructed and theoretically demonstrated. A mathematical model of the constructed OFCS is then built to investigate the effect of the peak-to-peak radio frequency (RF) signals applied to the MZM arms on the generated optical frequency comb (OFC) lines at the MZM output. A dual-drive MZM, a continuous wave laser source, and an RF signal source are included in the OFCS. The chirp parameter can be controlled and 64 comb lines generated at a comb spacing of 25 GHz by regulating voltages applied to the MZM arms. The developed OFCS is relatively simple but valuable. The generated OFC lines can be used for high data-rate transmission.

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I. Hammadi, Yousif, and Tahreer S. Mansour. "Relationship between the voltage applied to MZM arms and the generation of optical frequency comb." International Journal of Engineering & Technology 7, no. 4.15 (2018): 405. http://dx.doi.org/10.14419/ijet.v7i4.15.23591.

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In this study, an optical frequency comb source (OFCS) based on a dual-drive Mach–Zehnder modulator (MZM) is constructed and theoretically demonstrated. A mathematical model of the constructed OFCS is then built to investigate the effect of the peak-to-peak radio frequency (RF) signals applied to the MZM arms on the generated optical frequency comb (OFC) lines at the MZM output. A dual-drive MZM, a continuous wave laser source, and an RF signal source are included in the OFCS. The chirp parameter can be controlled and 64 comb lines generated at a comb spacing of 25 GHz by regulating voltages applied to the MZM arms. The developed OFCS is relatively simple but valuable. The generated OFC lines can be used for high data-rate transmission.

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Lalor, Edmund C., Alan J. Power, Richard B. Reilly, and John J. Foxe. "Resolving Precise Temporal Processing Properties of the Auditory System Using Continuous Stimuli." Journal of Neurophysiology 102, no. 1 (2009): 349–59. http://dx.doi.org/10.1152/jn.90896.2008.

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In natural environments complex and continuous auditory stimulation is virtually ubiquitous. The human auditory system has evolved to efficiently process an infinitude of everyday sounds, which range from short, simple bursts of noise to signals with a much higher order of information such as speech. Investigation of temporal processing in this system using the event-related potential (ERP) technique has led to great advances in our knowledge. However, this method is restricted by the need to present simple, discrete, repeated stimuli to obtain a useful response. Alternatively the continuous auditory steady-state response is used, although this method reduces the evoked response to its fundamental frequency component at the expense of useful information on the timing of response transmission through the auditory system. In this report, we describe a method for eliciting a novel ERP, which circumvents these limitations, known as the AESPA (auditory-evoked spread spectrum analysis). This method uses rapid amplitude modulation of audio carrier signals to estimate the impulse response of the auditory system. We show AESPA responses with high signal-to-noise ratios obtained using two types of carrier wave: a 1-kHz tone and broadband noise. To characterize these responses, they are compared with auditory-evoked potentials elicited using standard techniques. A number of similarities and differences between the responses are noted and these are discussed in light of the differing stimulation and analysis methods used. Data are presented that demonstrate the generalizability of the AESPA method and a number of applications are proposed.

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Hosseiny, B., J. Amini, M. Esmaeilzade, and M. Nekoee. "RANGE MIGRATION ALGORITHM IN THE PROCESSING CHAIN OF SIGNALS OF A GROUND-BASED SAR SENSOR." ISPRS - International Archives of the Photogrammetry, Remote Sensing and Spatial Information Sciences XLII-4/W18 (October 18, 2019): 521–25. http://dx.doi.org/10.5194/isprs-archives-xlii-4-w18-521-2019.

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Abstract. Synthetic aperture radar (SAR) system based on frequency modulated continuous wave (FM-CW) transmission is a viable option for producing high-resolution ground-based imaging radars. Compared with pulsed SAR systems, the combination of FM-CW technology and SAR processing techniques have the advantages of small cubage, lightweight, cost-effectiveness, and high resolution in the SAR image. These characteristics make FM-CW SAR suitable to be deployed as payload on ground Based SARs (GB-SARs) for environmental and civilian applications. In this paper, the Range Migration Algorithm (RMA) is used in the processing chain of a Ground-Based SAR (GB-SAR) sensor. The mentioned sensor has been developed in Microwave Remote Sensing Laboratory (MReSL) at the School of Surveying and Geospatial Engineering, the University of Tehran for the generation of a complex image from the raw signal. The raw signal is acquired with that sensor working at S-band, frequency modulating from 2.26 GHz to 2.59 GHz.

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Castellano-Muñoz, Manuel, Michael E. Schnee, and Anthony J. Ricci. "Calcium-induced calcium release supports recruitment of synaptic vesicles in auditory hair cells." Journal of Neurophysiology 115, no. 1 (2016): 226–39. http://dx.doi.org/10.1152/jn.00559.2015.

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Hair cells from auditory and vestibular systems transmit continuous sound and balance information to the central nervous system through the release of synaptic vesicles at ribbon synapses. The high activity experienced by hair cells requires a unique mechanism to sustain recruitment and replenishment of synaptic vesicles for continuous release. Using pre- and postsynaptic electrophysiological recordings, we explored the potential contribution of calcium-induced calcium release (CICR) in modulating the recruitment of vesicles to auditory hair cell ribbon synapses. Pharmacological manipulation of CICR with agents targeting endoplasmic reticulum calcium stores reduced both spontaneous postsynaptic multiunit activity and the frequency of excitatory postsynaptic currents (EPSCs). Pharmacological treatments had no effect on hair cell resting potential or activation curves for calcium and potassium channels. However, these drugs exerted a reduction in vesicle release measured by dual-sine capacitance methods. In addition, calcium substitution by barium reduced release efficacy by delaying release onset and diminishing vesicle recruitment. Together these results demonstrate a role for calcium stores in hair cell ribbon synaptic transmission and suggest a novel contribution of CICR in hair cell vesicle recruitment. We hypothesize that calcium entry via calcium channels is tightly regulated to control timing of vesicle fusion at the synapse, whereas CICR is used to maintain a tonic calcium signal to modulate vesicle trafficking.

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Geng, Daoshuang, Daoguo Yang, Miao Cai, and Lixia Zheng. "A Novel Microwave Treatment for Sleep Disorders and Classification of Sleep Stages Using Multi-Scale Entropy." Entropy 22, no. 3 (2020): 347. http://dx.doi.org/10.3390/e22030347.

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The aim of this study was to develop an integrated system of non-contact sleep stage detection and sleep disorder treatment for health monitoring. Hence, a method of brain activity detection based on microwave scattering technology instead of scalp electroencephalogram was developed to evaluate the sleep stage. First, microwaves at a specific frequency were used to penetrate the functional sites of the brain in patients with sleep disorders to change the firing frequency of the activated areas of the brain and analyze and evaluate statistically the effects on sleep improvement. Then, a wavelet packet algorithm was used to decompose the microwave transmission signal, the refined composite multiscale sample entropy, the refined composite multiscale fluctuation-based dispersion entropy and multivariate multiscale weighted permutation entropy were obtained as features from the wavelet packet coefficient. Finally, the mutual information-principal component analysis feature selection method was used to optimize the feature set and random forest was used to classify and evaluate the sleep stage. The results show that after four times of microwave modulation treatment, sleep efficiency improved continuously, the overall maintenance was above 80%, and the insomnia rate was reduced gradually. The overall classification accuracy of the four sleep stages was 86.4%. The results indicate that the microwaves with a certain frequency can treat sleep disorders and detect abnormal brain activity. Therefore, the microwave scattering method is of great significance in the development of a new brain disease treatment, diagnosis and clinical application system.

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LONGTIN, ANDRÉ, and MARTIN ST-HILAIRE. "ENCODING CARRIER AMPLITUDE MODULATIONS VIA STOCHASTIC PHASE SYNCHRONIZATION." International Journal of Bifurcation and Chaos 10, no. 10 (2000): 2447–63. http://dx.doi.org/10.1142/s0218127400001596.

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The firings of excitable systems can phase lock to periodic forcing. In many situations however, the firings are separated by a random number of forcing cycles, even though they occur near a preferred phase of the forcing. Also, the associated interspike interval histograms display peaks over a continuous range of integer multiples of the forcing period, and the peak heights are a unimodal function of increasing multiples of the period. This paper focusses on these patterns of stochastic phase synchronization and their alteration by physiologically relevant stimuli that modulate the amplitude of the periodic forcing. Specifically, two regimes of the FitzHugh–Nagumo system exhibiting stochastic phase locking are considered. We discuss how internal noise, originating from e.g. synaptic or conductance fluctuations, must interact with either suprathreshold or subthreshold dynamics, and in some instances with subthreshold chaos, to produce such firing patterns. These responses to constant amplitude "carriers" are then compared to those from carriers with random band-limited amplitude modulations (AM's). The comparison is based on the mean firing rate, as well as phase synchronization computed using a suitably defined input–output phase difference. Further, using the stimulus reconstruction technique to characterize synchrony between random AM's and spikes, the internal noise is shown to help transmit information about random carrier AM's in the subthreshold and slightly suprathreshold cases. This transmission also depends nonmonotonically on the carrier frequency. Our results provide biophysical insight into the dynamics of neural signal encoding that combines a mean rate code on long time scales and a precise temporal code based on phase locking on the shorter time scale of the carrier period.

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Schreiber, W. F., and J. Piot. "Video transmission by adaptive frequency modulation." IEEE Communications Magazine 26, no. 11 (1988): 68–76. http://dx.doi.org/10.1109/35.9130.

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Jun Tan and G. L. Stuber. "Frequency-domain equalization for continuous phase modulation." IEEE Transactions on Wireless Communications 4, no. 5 (2005): 2479–90. http://dx.doi.org/10.1109/twc.2005.853901.

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Bilgekul, H., and H. Amca. "Multicarrier transmission using quadrature frequency/phase modulation." Electronics Letters 32, no. 22 (1996): 2051. http://dx.doi.org/10.1049/el:19961386.

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Benedetto, S., and P. Poggiolini. "Highly bandwidth efficient transmission through continuous polarisation modulation." Electronics Letters 26, no. 17 (1990): 1392. http://dx.doi.org/10.1049/el:19900895.

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Sakamoto, T., T. Kawanishi, and M. Izutsu. "Continuous-phase frequency-shift keying with external modulation." IEEE Journal of Selected Topics in Quantum Electronics 12, no. 4 (2006): 589–95. http://dx.doi.org/10.1109/jstqe.2006.876181.

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Lee, Il-Min, Namje Kim, Eui Su Lee, Sang-Pil Han, Kiwon Moon, and Kyung Hyun Park. "Frequency modulation based continuous-wave terahertz homodyne system." Optics Express 23, no. 2 (2015): 846. http://dx.doi.org/10.1364/oe.23.000846.

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Ito, Hiroshi T. "Frequency-dependent signal transmission and modulation by neuromodulators." frontiers in Neuroscience 2, no. 2 (2008): 138–44. http://dx.doi.org/10.3389/neuro.01.027.2008.

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Seeburg, D. P. "Frequency-Dependent Modulation of Retinogeniculate Transmission by Serotonin." Journal of Neuroscience 24, no. 48 (2004): 10950–62. http://dx.doi.org/10.1523/jneurosci.3749-04.2004.

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Agrawal, Paras M., Dan C. Sorescu, Ronald D. Kay, et al. "Spectral line shapes in systems undergoing continuous frequency modulation." Journal of Chemical Physics 105, no. 7 (1996): 2686–700. http://dx.doi.org/10.1063/1.472132.

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Hari, R., and J. P. Mäkelä. "Neuromagnetic Responses to Frequency Modulation of a Continuous Tone." Acta Oto-Laryngologica 102, sup432 (1986): 26–32. http://dx.doi.org/10.3109/00016488609108882.

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Sato, K., S. Aoyagi, and T. Kitami. "Fiber Optic Video Transmission Employing Square Wave Frequency Modulation." IEEE Transactions on Communications 33, no. 5 (1985): 417–24. http://dx.doi.org/10.1109/tcom.1985.1096311.

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Matalgah, M. M., and R. M. Radaydeh. "Hybrid frequency-polarization shift-keying Modulation for optical transmission." Journal of Lightwave Technology 23, no. 3 (2005): 1152–63. http://dx.doi.org/10.1109/jlt.2005.843517.

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Zhang, Shi Kai, and Jian Li Jin. "Asymmetric Binary Frequency Shift Keying and its Frequency Attribute." Advanced Materials Research 765-767 (September 2013): 1236–39. http://dx.doi.org/10.4028/www.scientific.net/amr.765-767.1236.

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An innovative asymmetric binary frequency shift keying (ABFSK) modulation format is presented and studied both in the time domain and frequency domain. First, the modulation function is demonstrated, it shows a quasi-continuous phase attribute and an ability of high speed data modulation. Second, the domain attribute is studied; it has a high degree of energy centralization. Thus, a narrow occupied bandwidth can be achieved after a proper filtering. Then, the finite spectrum can be conserved to improve spectrum efficiency.

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Da Ros, Francesco, Stella Civelli, Simone Gaiarin, et al. "Dual-Polarization NFDM Transmission With Continuous and Discrete Spectral Modulation." Journal of Lightwave Technology 37, no. 10 (2019): 2335–43. http://dx.doi.org/10.1109/jlt.2019.2904102.

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Jin, Xiao-dong, Min-jian Zhao, Ling Sun, and Wen-li Shen. "Equalization for continuous phase modulation over frequency-selective fading channels." Journal of Zhejiang University-SCIENCE A 8, no. 12 (2007): 1884–88. http://dx.doi.org/10.1631/jzus.2007.a1884.

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Jiang Fei, Liu Zhong, Hu Wen, and Bao Bo-Cheng. "Dynamical design and analysis of continuous chaos frequency modulation signal." Acta Physica Sinica 59, no. 1 (2010): 116. http://dx.doi.org/10.7498/aps.59.116.

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Liu, Qiang, Zhenguo Jing, Zhenjie Xia, Zhiyuan Huang, and Wei Peng. "Fiber-Optic Ultrasonic Sensing via Quasi-Continuous Quadrature Frequency Modulation." IEEE Photonics Technology Letters 32, no. 21 (2020): 1385–88. http://dx.doi.org/10.1109/lpt.2020.3019007.

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Van Thillo, Wim, Francois Horlin, Jimmy Nsenga, Valery Ramon, Andre Bourdoux, and Rudy Lauwereins. "Low-complexity linear frequency domain equalization for continuous phase modulation." IEEE Transactions on Wireless Communications 8, no. 3 (2009): 1435–45. http://dx.doi.org/10.1109/twc.2009.080146.

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Saleem, Sajid, and Gordon L. Stuber. "Frequency-domain Equalization Techniques for Multi-h Continuous Phase Modulation." IEEE Transactions on Communications 62, no. 6 (2014): 1818–29. http://dx.doi.org/10.1109/tcomm.2014.2316815.

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