Bibliografias temáticas / Radio frequency modulation

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Literatura científica selecionada sobre o tema "Radio frequency modulation"

Autor: Grafiati

Publicado: 4 de junho de 2021

Última modificação: 6 de setembro de 2023

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Artigos de revistas sobre o assunto "Radio frequency modulation"

Yang, Kai, Zhanshan Sun, Ruiqi Mao, Yi Lin, Yi Liu, Qiang An e Yunqi Fu. "Wideband Rydberg atom-based receiver for amplitude modulation radio frequency communication". Chinese Optics Letters 20, n.º 8 (2022): 081203. http://dx.doi.org/10.3788/col202220.081203.

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Cho, Chihyun, Hyunji Koo, Jae-Yong Kwon, Joo-Gwang Lee e Tae-Weon Kang. "Measurement of Analog Modulation Index with a Calibrated Radio Frequency Attenuator". Journal of Electromagnetic Engineering and Science 21, n.º 2 (30 de abril de 2021): 87–94. http://dx.doi.org/10.26866/jees.2021.21.2.87.

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This paper presents a method for the accurate and traceable measurement of the analog modulation index. A calibrated step attenuator was used as the main apparatus because it has a higher dynamic range and lower uncertainty than a spectrum analyzer or an oscilloscope. In amplitude modulation (AM), the modulation index is obtained from the amplitude difference between the carrier and the first sideband, as in the conventional method. The resolution and calibration uncertainties of the step attenuator were propagated to the measurement uncertainty of the modulation index. The uncertainty produced by the impedance mismatch and repeatability was also included. For frequency modulation (FM) and phase modulation (PM), the modulation index, β, was estimated (with the step attenuator) from the spectrum of each sideband through the nonlinear fitting of the Bessel function. Thus, the uncertainty of the fitting process was added to the uncertainty of the measurement. The three modulations, AM, FM, and PM, exhibited an expanded uncertainty (approximately 95% confidence level, k = 2) of 0.372% for 50% nominal depth of the AM, 88.8 Hz for the peak frequency deviation of 10 kHz, and 0.88 mrad for a 0.1 radian modulation index, respectively.

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Bello, N., e F. O. Edeko. "Design of a Robust Orthogonal Frequency Division Multiplexing (OFDM) Transceiver for a Cognitive Radio Testbed". March 2022 6, n.º 1 (março de 2022): 13–27. http://dx.doi.org/10.36263/nijest.2022.01.0301.

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Primarily, a Cognitive Radio (CR) resolves the problem of spectrum scarcity and underutilization. However, it should also attain a good throughput and Quality of Service (QoS) as its objectives. These requirements are solely dependent on the modulation used. Though single carrier modulations such as Gaussian Minimum Shift Keying (GMSK) are highly spectral efficient, they are not robust to frequency selective fading. An implementation of multicarrier modulation supports high spectral efficiency and resistance to multipath fading. Therefore, in this paper, there is a comprehensive how-to-guide of the design of Orthogonal Frequency Division Multiplexing (OFDM) in cognitive radio using GNU Radio (GR) 3.8 that interfaces with Universal Software Radio Peripheral (USRP) B210s for video transmission. The implementation achieved allows for the choice of any modulation schemes out of four commonly used ones for communication of the payloads thus offering dynamism for use in a cognitive radio system. The effective implementation of the proposed methods in this paper is verified by the successful transmission and reception of a 4 minute 37 seconds MP4 video across the different choices of modulation schemes. It was observed that the error performance of the payloads degraded with higher constellation points however, the throughput was increased. Hence, the trade-off between error probability and throughput in the cognitive radio is based on the radio-scene metrics about the signal-to-noise ratio (SNR) of the available channels.

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Volkov, A. A., V. A. Kuzyukov e M. S. Morozov. "MODEM OPTIONS FOR DIGITAL RADIO COMMUNICATION SYSTEMS". World of Transport and Transportation 15, n.º 6 (28 de dezembro de 2017): 48–56. http://dx.doi.org/10.30932/1992-3252-2017-15-6-4.

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[For the English abstract and full text of the article please see the attached PDF-File (English version follows Russian version)].ABSTRACT New versions of the modulator and demodulator (modem) for the digital railway radio communication system GSM-R have been developed, which increase the noise immunity twofold. To realize «cos» and «sin» blocks, a phase modulator is used, two coherent quadrature demodulators are connected to its output in parallel. It is shown that «cos» block generates the signal cos [msinφ(t)], which is transferred to the operating frequency of the transmitter by means of subsequent blocks representing the structure of the one-side amplitude modulation driver, forming the final phase-modulated signal. It is proposed to detect an FM signal not from the modulation envelope, as it is done customary, but coherently, which excludes the quadrature component of the interference. Keywords: railway, radio communication, digital signal, Gaussian filter, modulation, coherent FM signal detector, noise immunity, frequency efficiency.

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Han, Huangpu, Fan Yang, Chenghao Liu, Zhengfang Wang, Yunpeng Jiang, Guangyue Chai, Shuangchen Ruan e Bingxi Xiang. "High-Performance Electro-Optical Mach–Zehnder Modulators in a Silicon Nitride–Lithium Niobate Thin-Film Hybrid Platform". Photonics 9, n.º 7 (19 de julho de 2022): 500. http://dx.doi.org/10.3390/photonics9070500.

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We analyzed a Mach–Zehnder electro-optical modulator based on a silicon nitride strip–loaded waveguide on 0.5 μm thick x-cut lithium niobate thin film. The optical and radio frequency parameters for two different modulator structures (Type I: packaged with 2 μm thick SiO2 and Type II: unpackaged) were simulated, calculated, and optimized. The Optical parameters included the single-mode conditions, effective indices, the separation distance between the electrode edge and the Si3N4-strip-loaded edge, optical power distribution, bending loss, optical field distribution, and half-wave voltage. The radio frequency parameters included the characteristic impedance, attenuation constant, radio frequency effective index, and −3 dB modulation bandwidth. According to the numerical simulation and theoretical analysis, the half-wave voltage product and the −3 dB modulation bandwidth were, respectively, 2.85 V·cm and 0.4 THz for Type I modulator, and 2.33 V·cm and 1.26 THz for Type II modulator, with a device length of 3 mm.

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Shantha Selva Kumari, R., e K. Seyatha. "Performance evaluation of hybrid modulation techniques for high speed radio over fiber communication system". International Journal of Modern Physics C 30, n.º 09 (setembro de 2019): 1950070. http://dx.doi.org/10.1142/s0129183119500700.

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In Radio over Fiber (RoF) technology, the optical network capacity is integrated with the wireless network. The main objective of this work is to enhance the performance behavior of optical fiber communication system in terms of BER, Received Power and Q-Factor. The proposed combined modulation technologies, such as Pulse Amplitude Frequency Modulation (PAFM), Differential Phase Shift Keying Amplitude Modulation (DPSKA), Offset Quadrature Phase Shift Keying Amplitude Modulation (OQPSKA), Quadrature Amplitude Frequency Modulation (QAFM), Frequency Phase Modulation (FPM) and Pulse Amplitude Phase Modulation (PAPM), are used to meet this objective. The input data are used for modulating the electrical carrier signal with a frequency of 250 and 255[Formula: see text]GHz. This hybrid modulation technique obtained the minimum BER of about [Formula: see text] in FPM technique. The maximum Q-Factor of 33 is obtained in QAFM technique. The obtained maximum received power is 0.79[Formula: see text]mW in OQPSKA technique.

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Luo, Junshan, Hao Wang, Fanggang Wang e Shilian Wang. "Secure Spatial Modulation via Radio Frequency Mirrors". IEEE Transactions on Vehicular Technology 69, n.º 8 (agosto de 2020): 9168–73. http://dx.doi.org/10.1109/tvt.2020.2999917.

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Bulyuk, A. N. "Radio-frequency electrooptic modulation in optical fibers". Soviet Journal of Quantum Electronics 22, n.º 10 (31 de outubro de 1992): 948–50. http://dx.doi.org/10.1070/qe1992v022n10abeh003638.

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Bai, Jiang Ling, Li Bin Zhong, Wen Hai Xu e Jian Lin. "Research on Optical Signal Carrier Transmission Technology". Advanced Materials Research 1022 (agosto de 2014): 193–96. http://dx.doi.org/10.4028/www.scientific.net/amr.1022.193.

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This paper studies the single-sideband RF signals in the optical carrier side than the problem. RF signals modulated optical carrier OSSB + C modulation index is usually small, leading edge modulated carrier radio frequency signal generated by the optical carrier ratio is not ideal. A design scheme based on three-arm and four-arm MZM MZM optimized optical carrier single sideband radio frequency signal containing the edge ratio. By adjusting the DC bias voltage of the modulator can control the carrier side than the light signal. For any modulation index, are able to make the optical carrier single sideband radio frequency signal containing edges than the optimal value of 0 dB, improving the performance of the system. The simulation also verify their feasibility.

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Xiang Jingfeng, 项静峰, 王利国 Wang Liguo, 任伟 Ren Wei, 李唐 Li Tang, 吕德胜 Lü Desheng e 刘亮 Liu Liang. "Frequency Noise Suppression of Single-Frequency Laser with Radio-Frequency Modulation". Chinese Journal of Lasers 44, n.º 5 (2017): 0501009. http://dx.doi.org/10.3788/cjl201744.0501009.

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Teses / dissertações sobre o assunto "Radio frequency modulation"

Bracht, Roger, Jeff Dimsdle, Dave Rich e Frank Smith. "RADIO FREQUENCY OVERVIEW OF THE HIGH EXPLOSIVE RADIO TELEMETRY PROJECT". International Foundation for Telemetering, 1998. http://hdl.handle.net/10150/607352.

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International Telemetering Conference Proceedings / October 26-29, 1998 / Town & Country Resort Hotel and Convention Center, San Diego, California
High explosive radio telemetry (HERT) is a project that is being developed jointly by Los Alamos National Laboratory and AlliedSignal FM&T. The ultimate goal is to develop a small, modular telemetry system capable of high-speed detection of explosive events, with an accuracy on the order of 10 nanoseconds. The reliable telemetry of this data, from a high-speed missile trajectory, is a very challenging opportunity. All captured data must be transmitted in less than 20 microseconds of time duration. This requires a high bits/Hertz microwave telemetry modulation code to insure transmission of the data within the limited time interval available.

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Blackard, Kenneth Lee. "Measurements and models of radio frequency impulsive noise inside buildings". Thesis, This resource online, 1991. http://scholar.lib.vt.edu/theses/available/etd-08182009-040318/.

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Gendron, Paul John. "A comparison of digital beacon receiver frequency estimators". Thesis, This resource online, 1993. http://scholar.lib.vt.edu/theses/available/etd-09292009-020307/.

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Bax, Walter T. "Modulation and frequency synthesis for wireless digital radio". Thesis, National Library of Canada = Bibliothèque nationale du Canada, 2000. http://www.collectionscanada.ca/obj/s4/f2/dsk1/tape4/PQDD_0019/NQ48341.pdf.

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Bax, Walter T. (Walter Timothy) Carleton University Dissertation Engineering Electronics. "Modulation and frequency synthesis for wireless digital radio". Ottawa, 1999.

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Caldera, Manora K. "Combined coding and modulation in frequency-selective mobile communications". Thesis, Curtin University, 2000. http://hdl.handle.net/20.500.11937/2493.

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Due to constraints on spectrum availability and transmitter power, both bandwidth and power efficient communication techniques are desirable for mobile radio. Continuous phase modulated (CPM) signals have gained attention because of their attractive power spectra (Steele, 1992). It has been shown that the trellis coded modulation (TCM) schemes could provide better bit error rate performances compared to the uncoded schemes (Ungerboeck, 1982). Therefore, the combination of TCM which improves error probability and CPM signals which yield low spectral occupancy is expected to provide good coding and modulation over bandwidth and power limited channels such as the one encountered in mobile radio communications.In this research, a Trellis Coded Modulation (TCM) scheme, which combines convolutional coding and partial response Continuous Phase Modulation (CPM) such as Gaussian Minimum Shift Keying (GMSK), is investigated. Also, this study concentrates on the use of rate-half convolutional codes, and GMSK (B(subscript)0T=0.3). The latter has been adopted in the Global System for Mobile Communications (GSM) system.Appropriate codes are selected assuming Maximum Likelihood Sequence Detection (MLSD) based on the Viterbi algorithm using an extensive computer search. The bit-error-rate (BER) performances of the selected trellis coded GMSK schemes are theoretically evaluated in the presence of additive white Gaussian noise (AWGN) and frequency-flat fading. In the case of fading, the analysis is simplified to assume only amplitude-fading, and without considering the effect of fading on the phase of the received signal.Computer simulations are used to evaluate the BER performances of the proposed trellis coded GMSK schemes in the presence of AWGN and practical impairments, such as sample timing offset and carrier phase errors. Coding gains of up to 2.2dB at a BER of 10(subscript)-3 are obtained under ideal sample timing and carrier recovery conditions. This has been achieved without increasing the receiver complexity based on the number of states in the Viterbi decoder, compared to the uncoded GMSK scheme. Furthermore, these coded schemes are more tolerant to sample timing and carrier phase impairments.Also, the BER performances of the proposed trellis coded GMSK schemes have been extensively investigated by computer simulations for frequency-flat and frequency-selective fading channels. In the case of frequency-selective fading, the Viterbi decoding is made adaptive to cater for the channel impulse response variations with time. With this adaptive receiver, the irreducible BERs of the coded scheme is found to be lower than that of the uncoded. Performance improvements are obtained with a trellis coded GMSK scheme using a constraint length 2 code with a Viterbi decoder of 16 states compared to the 128 states required for the uncoded scheme. Further, the coded scheme has shown less sensitivity to carrier phase errors, compared to the uncoded.

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Bracht, Roger. "RADIO FREQUENCY PATH CHARACTERIZATION FOR WIDE BAND QUADRATURE AMPLITUDE MODULATION". International Foundation for Telemetering, 1998. http://hdl.handle.net/10150/607351.

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International Telemetering Conference Proceedings / October 26-29, 1998 / Town & Country Resort Hotel and Convention Center, San Diego, California
Remote, high speed, high explosive wave front monitoring requires very high bandwidth telemetry to allow transmission of diagnostic data before the explosion destroys the sensor system itself. The main motivation for this study is that no known existing implementation of this sort has been applied to realistic weapons environments. These facts have prompted the research and gathering of data that can be used to extrapolate towards finding the best modulation method for this application. In addition to research of similar existing analysis and testing operations, data was recently captured from a Joint Test Assembly (JTA) Air Launched Cruise Missile (ALCM) flight.

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Davis, Kyle. "Radio frequency photonic in-phase and quadrature-phase vector modulation". Thesis, Georgia Institute of Technology, 2013. http://hdl.handle.net/1853/50354.

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The focus of this thesis is to investigate the implementation of Radio Frequency (RF) In-Phase and Quadrature-Phase (I/Q) vector modulation through the use of modern photonic components and sub-systems which offer extremely wide RF intrinsic bandwidths. All-electronic vector modulators suffer from frequency coverage limitations and amplitude and phase instability due to components such as phase shifters and variable gain controllers operating at or near 100\% bandwidth. In stark contrast, once an RF signal has been modulated onto an optical carrier, the percent bandwidth of the RF to carrier is typically less than 0.01\% percent. The fundamental mechanisms and basic electronic and photonic components needed to achieve vector modulation is introduced first. The primary electrical component required in most architectures is the 90° RF hybrid coupler, which is required to generate the RF I and Q terms. The two primary photonic building blocks, aside from the laser, electro-optic modulator and demodulator, are Mach-Zehnder Modulators (MZM) and Variable Optical Attenuators (VOA). Through the utilization of these components, multiple past architectures are explored and multiple new architectures are designed simulated. For each architecture, there is a discussion on the practical implementation. Considerations such as system complexity, integration, and sensitivity to unwanted environmental stimuli are taken into account with potential solutions to alleviate these risks. In closing, the noise figure and its impact on Spur-Free Dynamic Range (SFDR) for a basic RF photonic link is derived to provide a system-level figure of merit that can be used, in most RF applications, to determine the overall performance utility current and future designs.

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Caldera, Manora K. "Combined coding and modulation in frequency-selective mobile communications". Curtin University of Technology, School of Electrical and Computer Engineering, 2000. http://espace.library.curtin.edu.au:80/R/?func=dbin-jump-full&object_id=9820.

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Due to constraints on spectrum availability and transmitter power, both bandwidth and power efficient communication techniques are desirable for mobile radio. Continuous phase modulated (CPM) signals have gained attention because of their attractive power spectra (Steele, 1992). It has been shown that the trellis coded modulation (TCM) schemes could provide better bit error rate performances compared to the uncoded schemes (Ungerboeck, 1982). Therefore, the combination of TCM which improves error probability and CPM signals which yield low spectral occupancy is expected to provide good coding and modulation over bandwidth and power limited channels such as the one encountered in mobile radio communications.In this research, a Trellis Coded Modulation (TCM) scheme, which combines convolutional coding and partial response Continuous Phase Modulation (CPM) such as Gaussian Minimum Shift Keying (GMSK), is investigated. Also, this study concentrates on the use of rate-half convolutional codes, and GMSK (B(subscript)0T=0.3). The latter has been adopted in the Global System for Mobile Communications (GSM) system.Appropriate codes are selected assuming Maximum Likelihood Sequence Detection (MLSD) based on the Viterbi algorithm using an extensive computer search. The bit-error-rate (BER) performances of the selected trellis coded GMSK schemes are theoretically evaluated in the presence of additive white Gaussian noise (AWGN) and frequency-flat fading. In the case of fading, the analysis is simplified to assume only amplitude-fading, and without considering the effect of fading on the phase of the received signal.Computer simulations are used to evaluate the BER performances of the proposed trellis coded GMSK schemes in the presence of AWGN and practical impairments, such as sample timing offset and carrier phase errors. Coding gains of up to 2.2dB at a BER of 10(subscript)-3 ++
are obtained under ideal sample timing and carrier recovery conditions. This has been achieved without increasing the receiver complexity based on the number of states in the Viterbi decoder, compared to the uncoded GMSK scheme. Furthermore, these coded schemes are more tolerant to sample timing and carrier phase impairments.Also, the BER performances of the proposed trellis coded GMSK schemes have been extensively investigated by computer simulations for frequency-flat and frequency-selective fading channels. In the case of frequency-selective fading, the Viterbi decoding is made adaptive to cater for the channel impulse response variations with time. With this adaptive receiver, the irreducible BERs of the coded scheme is found to be lower than that of the uncoded. Performance improvements are obtained with a trellis coded GMSK scheme using a constraint length 2 code with a Viterbi decoder of 16 states compared to the 128 states required for the uncoded scheme. Further, the coded scheme has shown less sensitivity to carrier phase errors, compared to the uncoded.

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Ng, Man-hung. "Bandwidth-efficient pilot-symbol-aided techniques for fading estimation in multipath fading channels". Hong Kong : University of Hong Kong, 2001. http://sunzi.lib.hku.hk/hkuto/record.jsp?B22582174.

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Livros sobre o assunto "Radio frequency modulation"

Faruque, Saleh. Radio Frequency Modulation Made Easy. Cham: Springer International Publishing, 2017. http://dx.doi.org/10.1007/978-3-319-41202-3.

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Kissick, W. A. The intelligibility of amplitude companded sideband modulation compared to conventional frequency modulation. Washington, D.C: U.S. Dept. of Justice, Office of Justice Programs, National Institute of Justice, 1989.

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Institution, of Engineering and Technology International Conference on Ionospheric Radio Systems and Techniques (10th 2006 London England). The 10th Institution of Engineering and Technology International Conference on Ionospheric Radio Systems and Techniques: (IRST2006) : 18 -21 July 2006. London: The Royal Society of Medicine, 2006.

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Violette, E. J. Millimeter-wave propagation characteristics and channel performance for urban-suburban environments. [Boulder, CO]: U.S. Dept. of Commerce, National Telecommunications and Information Administration, 1988.

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F, Pavlenko I͡U. Izmerenie parametrov chastotno-modulirovannykh kolebaniĭ. Moskva: "Radio i svi͡azʹ", 1986.

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Nesenbergs, M. Power spectral densities for selected digital phase-continuous MFSK emissions. [Boulder, CO]: U.S. Dept. of Commerce, National Telecommunications and Information Administration, 1989.

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Capítulos de livros sobre o assunto "Radio frequency modulation"

Pfenninger, Susanne, Herman Cho, Jörg Forrer e Arthur Schweiger. "Radio Frequency Driven Electron Spin Echo Envelope Modulation". In 25th Congress Ampere on Magnetic Resonance and Related Phenomena, 443–44. Berlin, Heidelberg: Springer Berlin Heidelberg, 1990. http://dx.doi.org/10.1007/978-3-642-76072-3_230.

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Venkata Subbarao, M., e P. Samundiswary. "Spectrum Sensing in Cognitive Radio Networks Using Time–Frequency Analysis and Modulation Recognition". In Lecture Notes in Electrical Engineering, 827–37. Singapore: Springer Singapore, 2018. http://dx.doi.org/10.1007/978-981-10-7329-8_85.

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Grigoriev, Y., e V. Stepanov. "Microwave Effect on Embryo Brain: Dose Dependence and the Effect of Modulation". In Radio Frequency Radiation Dosimetry and Its Relationship to the Biological Effects of Electromagnetic Fields, 31–37. Dordrecht: Springer Netherlands, 2000. http://dx.doi.org/10.1007/978-94-011-4191-8_5.

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De Staerke, Danielle, e André Fontanel. "Study of the Modulation by Correlation in the Time and Frequency Domains of Wave Height and Microwave Signal". In Wave Dynamics and Radio Probing of the Ocean Surface, 529–40. Boston, MA: Springer US, 1986. http://dx.doi.org/10.1007/978-1-4684-8980-4_37.

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Yoo, Kwang Kiun, e Ronny Yongho Kim. "HiNet: Radio Frequency Communication Based Train Control (RF-CBTC) System Jointly Using Hierarchical Modulation and Network Coding". In Convergence and Hybrid Information Technology, 130–37. Berlin, Heidelberg: Springer Berlin Heidelberg, 2012. http://dx.doi.org/10.1007/978-3-642-32645-5_17.

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Renuka, N., e M. Satya Sairam. "Peak-to-Average Power Ratio Performance of Transform Precoding-Based Orthogonal Frequency Division Multiplexing Offset Quadrature Amplitude Modulation". In Smart Intelligent Computing and Applications, 241–48. Singapore: Springer Singapore, 2018. http://dx.doi.org/10.1007/978-981-13-1927-3_25.

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Li, Bingcheng. "Time Frequency Analysis for Radio Frequency (RF) Signal Processing". In Recent Advances of Wavelet Transform and Their Applications [Working Title]. IntechOpen, 2022. http://dx.doi.org/10.5772/intechopen.102821.

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In high-density radio frequency (RF) signal environments, receivers usually acquire signals from multiple sources. These RF signals may be co-channel and co-duration, which cause significant difficulties for processing them. Time-Frequency analysis combined with a projection pursuits graph approach provides an effective way to detect, separate, and classify these multiple source RF signals. Time-frequency analysis includes a spectrogram approach and a scalogram approach. The feature points on the instantaneous frequency function of a frequency modulation radio frequency (FMRF) signal can be extracted from either the spectrogram or scalogram of this FMRF signal. With the projection pursuits graph approach, these feature points are grouped into time-frequency functions to represent the multiple components for the separation, detection, and classification of this multisource FMRF signal.

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Rohling, Hermann. "OFDM Transmission Technique". In Mobile Computing, 3561–87. IGI Global, 2009. http://dx.doi.org/10.4018/978-1-60566-054-7.ch260.

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The orthogonal frequency division multiplexing (OFDM) transmission technique can efficiently deal with multi-path propagation effects especially in broadband radio channels. It also has a high degree of system flexibility in multiple access schemes by combining the conventional TDMA; FDMA; and CDMA approaches with the OFDM modulation procedure; which is especially important in the uplink of a multi-user system. In OFDM-FDMA schemes carrier synchronization and the resulting sub-carrier orthogonality plays an important role to avoid any multiple access interferences (MAI) in the base station receiver. An additional technical challenge in system design is the required amplifier linearity to avoid any non-linear effects caused by a large peak-to-average ratio (PAR) of an OFDM signal. The OFDM transmission technique is used for the time being in some broadcast applications (DVB-T; DAB; DRM) and wireless local loop (WLL) standards (HIPERLAN/2; IEEE 802.11a) but OFDM has not been used so far in cellular communication networks. The general idea of the OFDM scheme is to split the total bandwidth into many narrowband sub-channels which are equidistantly distributed on the frequency axis. The sub-channel spectra overlap each other but the sub-carriers are still orthogonal in the receiver and can therefore be separated by a Fourier transformation. The system flexibility and use of sub-carrier specific adaptive modulation schemes in frequency selective radio channels are some advantages which make the OFDM transmission technique a strong and technically attractive candidate for the next generation of mobile communications. The objective of this chapter is to describe an OFDM-based system concept for the fourth generation (4G) of mobile communications and to discuss all technical details when establishing a cellular network which requires synchronization in time and frequency domain with sufficient accuracy. In this cellular environment a flexible frequency division multiple access scheme based on OFDM-FDMA is developed and a radio resource management (RRM) employing dynamic channel allocation (DCA) techniques is used. A purely decentralized and self-organized synchronization technique using specific test signals and RRM techniques based on co-channel interference (CCI) measurements has been developed and will be described in this chapter.

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Omer, Ala Eldin. "Review of Spectrum Sensing Techniques in Cognitive Radio Networks". In Advances in Wireless Technologies and Telecommunication, 85–107. IGI Global, 2019. http://dx.doi.org/10.4018/978-1-5225-5354-0.ch005.

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Most frequency spectrum bands are licensed to certain services to avoid the interference between various networks, but the spectrum occupancy measurements show that few portions of this spectrum are fully efficiently used. Cognitive radio is a future radio technology that is aware of its environment, internal state, and can change its operating behavior (transmitter parameters) accordingly. Through this technology the unlicensed users can use the underutilized spectrum without causing any harmful interference to the licensed users. Its key domains are sensing, cognition, and adaptation. The spectrum sensing problem is one of the most challenging issues in cognitive radio systems to detect the available frequency bands. This chapter introduces the concepts of various transmitter detection techniques, namely energy detection, matched filter detection, and cyclostationary feature detection. The chapter also discusses other sensing techniques that are introduced to enhance the detection performance of the conventional energy detector. Additionally, the introduced sensing techniques are implemented using extensive MATLAB simulations and their performances are evaluated and compared in terms of sensing time, detection sensitivity, and ease of implementation. The implementation is based on BPSK and QPSK modulation schemes under various SNR values for AWGN noisy channel with Rayleigh fading.

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Lewis, Tom. "Armstrong and the FM Revolution". In Empire of the Air, 247–79. Cornell University Press, 2021. http://dx.doi.org/10.7591/cornell/9781501759321.003.0011.

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This chapter unravels Howard Armstrong's creation of wide-band frequency modulation — FM. It follows a trail of research from hundreds of thousands of tests and measurements, tens of thousands of hours of work for Armstrong and his assistants, to ultimate triumph. Like most revolutions, Armstrong's FM had been a long time in the making. The chapter argues that Armstrong began exploring the nature of frequency modulated waves in as thorough a way as he had the operation of the vacuum tube and the phenomenon of static. The chapter then tracks Armstrong's fundamental changes in the radio receiver. The chapter investigates the challenges and hearings faced by Armstrong. It became clear to all in radio that new portions of the spectrum were needed for television, police, and government communications as well as FM. The chapter then recounts how the introduction of FM began to move more swiftly.

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Trabalhos de conferências sobre o assunto "Radio frequency modulation"

Shum, Chi-Man, e Edward A. Whittaker. "Resonantly enhanced radio frequency electrooptic phase modulator". In OSA Annual Meeting. Washington, D.C.: Optica Publishing Group, 1989. http://dx.doi.org/10.1364/oam.1989.tht6.

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We recently developed a novel scheme1 to overcome the residual amplitude modulation (RAM) background of frequency modulation spectroscopy.2 This technique calls for a specially designed laser phase modulator with high response at one rf frequency and modest response at the harmonic of that frequency. To that end, we have modified the usual modulator design by fabricating an inductively loaded device with resonant response adjustable from ~150 to 350 MHz depending on the size of the inductor. At the highest resonance frequency, we observed a modulation index enhancement of as much as 80% over that obtained with an unloaded modulator. We report here the results of extensive computer modeling and experimental characterization of the new device. The model contains a resonator formed by an external inductor in parallel with the electrooptic crystal. The parasitic effects of the microstrip are represented by additional series inductance and parallel capacitance. Agreement between the model and experiment is quite satisfactory.

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Walling, Jeffrey S., Stewart S. Taylor e David J. Allstot. "Multiple supply (class-G) linear modulator and PA for non-CE modulation". In 2009 IEEE Radio Frequency Integrated Circuits Symposium (RFIC). IEEE, 2009. http://dx.doi.org/10.1109/rfic.2009.5135610.

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Liu, Chenxia, Tao Liu, Tianwei Jiang e Song Yu. "Stable 2.4 GHz Radio Frequency Transmission Based on Phase Modulation". In 2022 Joint Conference of the European Frequency and Time Forum and IEEE International Frequency Control Symposium (EFTF/IFCS). IEEE, 2022. http://dx.doi.org/10.1109/eftf/ifcs54560.2022.9850722.

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Li, Difei, Fan Wu, Kejia Zhao, Zhijun Yang, Zhaochun Wu, Zhigang Feng e He Chen. "A traceable method for measuring modulation error ratio of radio frequency signals". In 2016 IEEE International Conference on Mechatronics and Automation. IEEE, 2016. http://dx.doi.org/10.1109/icma.2016.7558856.

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Wan, Wenjian, Hua Li e Juncheng Cao. "Broadband Terahertz Quantum Cascade Laser with Radio Frequency Modulation". In International Symposium on Ultrafast Phenomena and Terahertz Waves. Washington, D.C.: OSA, 2018. http://dx.doi.org/10.1364/isuptw.2018.tuk15.

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Urbansky, Lars, e Udo Zolzer. "A Digital Radio-Frequency Condenser Microphone with Amplitude Modulation". In 2019 IEEE International Symposium on Circuits and Systems (ISCAS). IEEE, 2019. http://dx.doi.org/10.1109/iscas.2019.8702611.

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Song, Hyejeong, e Ranjit Gharpurey. "Digitally intensive transmitter employing RF pulse width modulation for IoT applications". In 2015 IEEE Radio Frequency Integrated Circuits Symposium (RFIC). IEEE, 2015. http://dx.doi.org/10.1109/rfic.2015.7337727.

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Baranov, Y., K. Kirov, M. Goniche, J. Mailloux, M. L. Mayoral, J. Ongena, F. Nave, Volodymyr Bobkov e Jean-Marie Noterdaeme. "LH power modulation experiment on JET". In RADIO FREQUENCY POWER IN PLASMAS: Proceedings of the 18th Topical Conference. AIP, 2009. http://dx.doi.org/10.1063/1.3273763.

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Chi-Tsan Chen, Chien-Jung Li, Tzyy-Sheng Horng, Je-Kuan Jau e Jian-Yu Li. "Design and linearization of Class-E power amplifier for non-constant envelope modulation". In 2008 IEEE Radio Frequency Integrated Circuits Symposium (RFIC). IEEE, 2008. http://dx.doi.org/10.1109/rfic.2008.4561405.

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Geng, Xueyang, Fa Foster Dai, J. David Irwin e Richard C. Jaeger. "A 5 GHz direct digital synthesizer MMIC with direct modulation and spur randomization". In 2009 IEEE Radio Frequency Integrated Circuits Symposium (RFIC). IEEE, 2009. http://dx.doi.org/10.1109/rfic.2009.5135571.

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Relatórios de organizações sobre o assunto "Radio frequency modulation"

DEFENSE SCIENCE BOARD WASHINGTON DC. Wideband Radio Frequency Modulation: Dynamic Access to Mobile Information Networks. Fort Belvoir, VA: Defense Technical Information Center, julho de 2003. http://dx.doi.org/10.21236/ada417214.

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Hayes, Robert R. High Linearity Wideband Coherent Amplitude Modulation (AM) Radio Frequency (RF)-Photonic Links. Fort Belvoir, VA: Defense Technical Information Center, outubro de 2005. http://dx.doi.org/10.21236/ada440576.

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Fischer W., P. Cameron, S. Peggs e T. Satogata. Tune Modulation from Beam-Beam Interaction and Unequal Radio Frequency in RHIC. Office of Scientific and Technical Information (OSTI), maio de 2002. http://dx.doi.org/10.2172/1061666.

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Lei, Ming, Alexandra Duel-Hallen e Hans Hallen. Reliable Adaptive Modulation and Interference Mitigation for Mobile Radio Slow Frequency Hopping Channels. Fort Belvoir, VA: Defense Technical Information Center, agosto de 2008. http://dx.doi.org/10.21236/ada500343.

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DEFENSE SCIENCE BOARD WASHINGTON DC. Report of the Defense Science Board Task Force on Wideband Radio Frequency Modulation: Dynamic Access to Mobile Information Networks. Fort Belvoir, VA: Defense Technical Information Center, julho de 2003. http://dx.doi.org/10.21236/ada428978.

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NTP Technical Report on the Toxicology and Carcinogenesis Studies in B6C3F1/N Mice Exposed to Whole-Body Radio Frequency Radiation at a Frequency (1,900 MHz) and Modulations (GSM and CDMA) Used by Cell Phones. NIEHS, novembro de 2018. http://dx.doi.org/10.22427/ntp-tr-596.

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NTP Technical Report on the Toxicology and Carcinogenesis Studies in Hsd:Sprague Dawley SD Rats Exposed to Whole-Body Radio Frequency Radiation at a Frequency (900 MHz) and Modulations (GSM and CDMA) Used by Cell Phones. NIEHS, novembro de 2018. http://dx.doi.org/10.22427/ntp-tr-595.

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