Journal articles: 'Modulation and Demodulation'

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Li, Peng Fei, Jin Ping Li, and Xin Zhao. "Design and Simulation of 2PSK Modem." Applied Mechanics and Materials 321-324 (June 2013): 2914–18. http://dx.doi.org/10.4028/www.scientific.net/amm.321-324.2914.

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Based on the principle of the modulation and demodulation of Binary Phase Shift Keying(2PSK),a mathematical model for the modulation and demodulation of the 2PSK was built and the carrier signal was designed using the technology of Direct Digital Synthesis (DDS).Then,a model to simulate the hardware circuit of the modulation and demodulation of 2PSK was built,and then analyzed in Matlab and Modelsim.Simulation results show that the model not only properly realizes the function of 2PSK modulator-demodulator,but it also simplifies the hardware circuit and reduces the programming time.

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Mu, Shi Guang, Jin Rong Bai, and Xiu Feng Shi. "Optimization and Simulation of Demodulation and Decoding of the LDPC-BICM-ID System." Applied Mechanics and Materials 701-702 (December 2014): 1088–92. http://dx.doi.org/10.4028/www.scientific.net/amm.701-702.1088.

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In the bit interleaving coded modulation (BICM-ID) solution,includes the demodulator and decoder into the iteration and decoding process, and the decoding is completed between demodulator and decoder. In studies, it have been found that the oscillation is generated on logarithmic likelihood ratio (LLR) because the soft information generated by all previous BP iterations is ignored in this solution, so that the BP soft information output by the final BP iterative decoding is not always reliable. In this paper, the above problem is solved by optimizing the iterative demodulation and decoding solution. Aiming at this problem, this paper firstly puts forward a kind of optimization scheme about iterative demodulation and decoding, then the simulation analysis, the result show that, under the premise of ensuring the system complexity basically unchanged, can improve the demodulation and decoding performance of LDPC coded modulation and demodulation system.

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Liu, Xiao Jian, Wei Xu, and Jue Wang. "LDPC Coded PPM and Iterative Detection for Free-Space Optical Links." Applied Mechanics and Materials 651-653 (September 2014): 444–50. http://dx.doi.org/10.4028/www.scientific.net/amm.651-653.444.

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The pulse position modulation, which has the advantage of average energy efficiency and bandwidth efficiency, is an attractive modulation scheme for free-space optical communication. An important practical issue is to employ an efficient channel coding to this modulation. In this view, we consider the use of low density parity-check code together with iterative soft demodulation and channel decoding at the receiver. In particular, we discuss the calculation of the soft information at the demodulator to accommodate the LDPC decoder. We show that the proposed scheme is quite efficient against demodulation errors due to the receiver noise.

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Li, Guo Quan, Ke Tang, Jin Zhao Lin, Yu Pang, Zhang Yong Li, Qian Neng Zhou, and Lu Deng. "Exploration of Modulation and Demodulation for Body Area Networks." Applied Mechanics and Materials 427-429 (September 2013): 2558–61. http://dx.doi.org/10.4028/www.scientific.net/amm.427-429.2558.

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Modulation and demodulation are two important parts in BAN baseband transmission systems. Different demodulation algorithms may affect the BER performance of the entire system seriously. Referring to IEEE 802.15.6 BAN standard, theoretical analysis and algorithm design of the modulation and demodulation for π/2-DBPSK and π/4-DQPSK is carried out and simulation results of BER performance are presented in this paper. In AWGN channel, both modulations achieve good performance, and performance degradation of π/4-DQPSK happens in multipath channel which may not satisfy the requirements. Adaptive modulation is considered to solve this problem by choosing different modulation scheme according to channel quality.

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Sud, Seema. "High Order Chirp Rate Shift Keying Modulation Using the Fractional Fourier Transform." European Journal of Engineering Research and Science 2, no. 4 (April 14, 2017): 1. http://dx.doi.org/10.24018/ejers.2017.2.4.314.

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In this paper, we discuss an improved demodulation scheme using the Fractional Fourier Transform (FrFT) for a modulation scheme employing chirp rate shift keying (CrSK). CrSK in conjunction with the FrFT enable very high order, e.g. more than 32-ary modulation schemes to be achievable with good bit error rate (BER) performance, even in the absence of coding, thereby overcoming limitations of traditional schemes including phase shift keying (PSK) or QAM (quadrature amplitude modulation). By using an FrFT-based demodulator, we expand our demodulation degrees of freedom from a single (e.g. frequency) axis to an entire time-frequency domain, called the Wigner Distribution (WD). We show how the proposed demodulation scheme using the FrFT improves over past approaches by more than 7 dB, enabling us to achieve close to 4-ary performance with a 32-ary modulation scheme. This enables future systems to operate at 5 bits/s/Hz bandwidth efficiency, enhancing bandwidth utilization for future generation, high data rate, applications, such as internet.

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Li, Minwei, Yang Yu, Yang Lu, Xiaoyang Hu, Yaorong Wang, Shangpeng Qin, Junyang Lu, Junbo Yang, and Zhenrong Zhang. "Optical Microfiber All-Optical Phase Modulator for Fiber Optic Hydrophone." Nanomaterials 11, no. 9 (August 28, 2021): 2215. http://dx.doi.org/10.3390/nano11092215.

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In order to meet the needs of phase generated carrier (PGC) demodulation technology for interferometric fiber optic hydrophones, we proposed an optical microfiber all-optical phase modulator (OMAOPM) based on the photo-induced thermal phase shift effect, which can be used as a phase carrier generation component, so as to make the modulation efficiency and working bandwidth of this type of modulator satisfy the requirements of underwater acoustic signal demodulation applications. We analyzed the modulation principle of this modulator and optimized the structural parameters of the optical microfiber (OM) when the waist length and waist diameter of OM are 15 mm and 1.4 μm, respectively. The modulation amplitude of the modulator can reach 1 rad, which can meet the requirements of sensing applications. On this basis, the fiber optical hydrophone PGC-Atan demodulation system was constructed, and the simulated underwater acoustic signal test demodulation research was carried out. Experimental results showed that the system can demodulate underwater acoustic signals below 1 kHz.

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Zhu, Shou Zhong, Zheng Liu, and Wen Li Jiang. "Counteraction of Constant Modulus Demodulation Scheme for Mixing Space Borne AIS Signals." Applied Mechanics and Materials 340 (July 2013): 523–28. http://dx.doi.org/10.4028/www.scientific.net/amm.340.523.

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Demodulation scheme was proposed in satellite systems to received Automatic Identification Systems (AIS) signals, with the potential presence of other interfering signals. The counteraction of constant modulus demodulation scheme, referred to as CCMDS, yields a set of single short signals based on the prior information of AIS after estimating the frequency, code rate and modulation index. It demodulates the corresponding short codes according to the constant modulus characters of GMSK signals. The proposed demodulation scheme is simple and easy to implement. Simulations show the satisfying performance and engineering value in demodulating the mixing AIS signals.

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Kajur, Renuka, and K. V. Prasad. "Design and analysis of optimized CORDIC based GMSK system on FPGA platform." International Journal of Electrical and Computer Engineering (IJECE) 10, no. 5 (October 1, 2020): 4679. http://dx.doi.org/10.11591/ijece.v10i5.pp4679-4686.

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The Gaussian minimum shift keying (GMSK) is one of the best suited digital modulation schemes in the global system for mobile communication (GSM) because of its constant envelop and spectral efficiency characteristics. Most of the conventional GMSK approaches failed to balance the digital modulation with efficient usage of spectrum. In this article, the hardware architecture of the optimized CORDIC-based GMSK system is designed, which includes GMSK Modulation with the channel and GMSK Demodulation. The modulation consists of non-return zero (NRZ) encoder, an integrator followed by Gaussian filtering and frequency modulation (FM). The GMSK demodulation consists of FM demodulator, followed by differentiation and NRZ decoder. The FM Modulation and demodulation use the optimized CORDIC model for an In-phase (I) and quadrature (Q) phase generation. The optimized CORDIC is designed by using quadrant mapping and pipelined structure to improve the hardware and computational complexity in GMSK systems. The GMSK system is designed on the Xilinx platform and implemented on Artix-7 and Spartan-3EFPGA. The hardware constraints like area, power, and timing utilization are summarized. The comparison of the optimized CORDIC model with similar CORDIC approaches is tabulated with improvements.

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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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Chen, Xian Qing, Shu Bo Song, and Wu Zhou. "Demodulation of a M-Ray Position Phase Shift Keying System Using Multi-Class Support Vector Machine Classification." Applied Mechanics and Materials 687-691 (November 2014): 3840–43. http://dx.doi.org/10.4028/www.scientific.net/amm.687-691.3840.

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In this paper, we introduce a new approach for nonlinear demodulation based on multi-class support vector machine (SVM) classification. We propose to measure the performance of this demodulator with different M which is the parameter of M-ray position phase shift keying (MPPSK) modulation, and compare with other demodulation technique. During demodulation, a few sampling points are chosen for multi-class SVM training and testing, which can reduce the complexity of system. Simulation results show that this new approach significantly outperforms the method of using Phase Locked Loop (PLL) demodulation by 10dB, and also better than Back Propagation Artificial Neural Networks (ANN-BP) classification demodulation. With the growth of M, the data rate increased and the performance become a little worse, but less bit SNR is used to achieve the same Symbol Error Rate (SER) as small M. So, it is an effective method to get better performance by using multi-class SVM classification technique for demodulation in MPPSK system.

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Ruppert, Michael G., David M. Harcombe, Michael R. P. Ragazzon, S. O. Reza Moheimani, and Andrew J. Fleming. "A review of demodulation techniques for amplitude-modulation atomic force microscopy." Beilstein Journal of Nanotechnology 8 (July 10, 2017): 1407–26. http://dx.doi.org/10.3762/bjnano.8.142.

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In this review paper, traditional and novel demodulation methods applicable to amplitude-modulation atomic force microscopy are implemented on a widely used digital processing system. As a crucial bandwidth-limiting component in the z-axis feedback loop of an atomic force microscope, the purpose of the demodulator is to obtain estimates of amplitude and phase of the cantilever deflection signal in the presence of sensor noise or additional distinct frequency components. Specifically for modern multifrequency techniques, where higher harmonic and/or higher eigenmode contributions are present in the oscillation signal, the fidelity of the estimates obtained from some demodulation techniques is not guaranteed. To enable a rigorous comparison, the performance metrics tracking bandwidth, implementation complexity and sensitivity to other frequency components are experimentally evaluated for each method. Finally, the significance of an adequate demodulator bandwidth is highlighted during high-speed tapping-mode atomic force microscopy experiments in constant-height mode.

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Chaudhari, Sandeep C., Yashwant Gupta, Ajith Kumar, Navnath D. Shinde, Sweta Gupta, and Ajay Vishwakarma. "Reducing Effects of Cross-Talk in a Radio Telescope Using Walsh Modulation." Journal of Astronomical Instrumentation 06, no. 01 (March 2017): 1641017. http://dx.doi.org/10.1142/s2251171716410178.

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Traditional Walsh technique is used to eliminate cross-talk in a array of radio telescope where achieving synchronization between modulator and demodulator without compromising sensitivity is a real challenge. The paper describes a novel approach named Walsh Delay Hunting (WDH) to synchronize independently running modulator and demodulator with no additional hardware. This approach is unique and can easily be implemented in any existing radio telescope with minimal changes, thus by putting Walsh modulator at telescope and demodulation can be done in digital back-end. The scheme greatly reduces antenna electronics and overhead of sending synchronizing Walsh start pulse back to center station and vice versa. The paper describes WDH method and its feasibility study for Giant Meterwave Radio Telescope (GMRT) along with test results. The modulator is a low cost CPLD-based module and demodulation is done in a Reconfigurable Open Architecture Computing Hardware (ROACH)-based digitizer and packetizer. The scheme requires noise injection facility before modulator, which GMRT has for antenna calibration.

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Zhang, Xudong, and Haiyu Ji. "Analysis and Simulation about a Simplified Model for Modulation and Demodulation of Ship-borne Single Channel Monopulse Radar." MATEC Web of Conferences 232 (2018): 04043. http://dx.doi.org/10.1051/matecconf/201823204043.

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A simplified mathematical model for modulation and demodulation of a single channel monopulse (SCM) system is proposed, which is based on a ship-borne pulse radar S-band guided receiver. Using the proposed mathematical model, the modulation and demodulation of single-channel and multi-channel signals were simulated respectively, and the factors influencing the modulation and demodulation of the SCM system were analysed.

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Zhu, Jin, and Dan Dan Yan. "Implementation of QPSK Modulation and Demodulation of FPGA." Applied Mechanics and Materials 427-429 (September 2013): 880–83. http://dx.doi.org/10.4028/www.scientific.net/amm.427-429.880.

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This paper studies the realization method of QPSK modulation and demodulation circuit based on FPGA.And the simulation results are given under the environment of MAX+PLUSII .In this paper, the scheme uses phase selection method, compared with the modulation and demodulation method commonly used, design more simple, more suitable for FPGA implementation, the reliability of the system is higher.Through the analysis of the simulation waveform shows, the very good realization of the QPSK modulation and demodulation function.

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Ali, Mohamed Syed. "Reconfigurable Modulation Scheme for Communication System." Indonesian Journal of Electrical Engineering and Computer Science 9, no. 3 (March 1, 2018): 624. http://dx.doi.org/10.11591/ijeecs.v9.i3.pp624-628.

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<p>In any communication system transmitter and receiver are used to transmit the signal via wired or wireless channel. In the transmitter, modulation is one of the processes to transmit the signal efficiently. Likewise, receiver contains demodulation to recover the original signal from the transmitter. In general, the communication system uses one modulation/demodulation process at a time. It cannot use different modulation/demodulation within a single system. To overcome this problem reconfiguration technique is implemented. It is the method using different modulation scheme at the same time. It will increase the efficiency of the communication system. QPSK and BPSK modulation technique is used to transmit and receive the signal.</p>

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Wang, Hui Bo, and Zhi Quan Li. "Research on Modulation Multiplexing System and Technique Employing Tilted Grating." Applied Mechanics and Materials 397-400 (September 2013): 1643–47. http://dx.doi.org/10.4028/www.scientific.net/amm.397-400.1643.

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A dual demodulation technique based on tilted grating and InGaAs photodiode array is proposed; using the coupling modes of the cladding, a wavelength demodulation method with the tilted grating as the spectroscopic device is realized. This method can achieve that the demodulation of the channel in which the sensing information changed and the optimization of collection rules of the system. Two tunable F-P filters scan and demodulate the sensing path simultaneously to further improve the system response speed. Simulation analysis and experiments results indicate that the average demodulation time is 40ms and the average signal frequency can reach 15Hz. In addition, the demodulation bandwidth is 40nm, and its wavelength demodulation precision can reach 20pm. The system has advantages of the shorter delay time, and the demodulation time is immune to the number of channels, etc.. Therefore, this system is able to meet the smart requirement of some complex systems and large scale distributed intelligent system.

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Assoumane, A., E. Sekko, and P. Ravier. "Kalman Filtering using Trigonometric Polynomials for Gear Fault Diagnosis Under a Variable Speed Condition." International Journal of Condition Monitoring 9, no. 1 (April 1, 2019): 8–13. http://dx.doi.org/10.1784/204764200409905165.

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It is well known that the presence of cracks on a gear tooth is manifested by both amplitude modulation (AM) and phase modulation (PM) and their estimation is crucial for the diagnosis and prognosis of the state of the gearbox. In this paper, a new demodulation technique for gear fault diagnosis is proposed based on Kalman filtering combined with a polynomial basis function of the rotating speed. First, the problem of demodulation is formulated in terms of the state-space modelling of the vibration signal. This is achieved by approximating the modulations using the orthogonal trigonometric polynomial function of the rotating speed. Kalman filtering is then used to estimate the coefficients of the polynomials in order to reconstruct the modulation signals. This approach is different from classic approaches such as the narrowband demodulation technique (NBDT) or time-synchronous averaging (TSA). The advantages of the proposed approach over the latter are discussed in this paper and the efficiency of the new approach is also evaluated using both synthetic and real gearbox vibration signals.

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Chernoyarov, Oleg, Alexey Glushkov, Vladimir Litvinenko, Yuliya Litvinenko, and Boris Matveev. "Digital Demodulator of the Quadrature Amplitude Modulation Signals." Measurement Science Review 18, no. 6 (October 1, 2018): 236–42. http://dx.doi.org/10.1515/msr-2018-0032.

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Abstract In this paper, the digital algorithm and the device for the demodulation of the quadrature amplitude modulation signals are considered. The fundamental advantages of our approach are simple hardware implementation, minimal number of arithmetic operations required over the signal period as well as the potential interference immunity in the presence of Gaussian noise. The expressions have been found for the error probability and their inaccuracy has been estimated. By means of the statistical simulation methods, the practical interference immunity of the introduced demodulator, together with the influence of phase locking errors have been tested. The introduced demodulator can be implemented either as a device independent from the programmable logic devices, or as an installation unit of the receiver equipment.

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Zhou, Fan, Xin Xin Geng, and Xiao Yu Zhang. "An Improved QPSK Signal's Algorithm Design and Simulation of its Modulation and Demodulation." Advanced Materials Research 912-914 (April 2014): 1146–49. http://dx.doi.org/10.4028/www.scientific.net/amr.912-914.1146.

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QPSK, a modulation mode with a high frequency band utilization ratio and a strong anti-noise immunity,is widely used in the field of military and satellite communication. This article based on the analysis of the traditional QPSK signal modulation and demodulation mechanism, proposes an improved QPSK signal modulation and demodulation algorithm, and have a further in-depth analysis of the feasibility of this algorithm. Finally, by MATLAB software simulation testing, simulation results shows that the algorithm can accurately generate a QPSK signal and complete a rapidly demodulation of a QPSK signal.

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Zou, Qin, and Min Wang. "Fast Demodulation Algorithm for Rate Compatible Modulation by Log-Map Principle." Advanced Materials Research 945-949 (June 2014): 2310–14. http://dx.doi.org/10.4028/www.scientific.net/amr.945-949.2310.

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Rate compatible modulation (RCM) is a promising technology to smooth rate adaption of physical layer in wireless network, and do not request the accurate channel estimation. Since RCM demodulation adopt probability convolution operator in belief propagation algorithm, it greatly bring big computing complexity. This paper proposes fast demodulation algorithm for RCM by using log-map principle. First, we propose a new demodulation algorithm by a novel approach to convert arithmetic domain to logarithm domain. Then, we design a parallel manner that to find multivariable computation in Log-MAP algorithm for hard implementation. Finally, we evaluate fast demodulation algorithm by two evaluation metrics BER and goodput, respectively. Our analysis show that the demodulation complexity can be reduced about 90%. While experimental results show that the fast demodulation algorithm performance only has a marginal loss.

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Gao, Xiao Peng, Si Yuan Wang, and Han Wan. "Accelerate Demodulation of Quadrature Amplitude Modulation Using GPU." Applied Mechanics and Materials 325-326 (June 2013): 907–11. http://dx.doi.org/10.4028/www.scientific.net/amm.325-326.907.

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Quadrature amplitude modulation (QAM) is widely used in communication systems. The traditional QAM demodulation method was implemented in hardware. This paper proposes a demodulation algorithm using GPU. The GPU algorithm is easier to add new features than hardware implementation and reaches 57x speed up compared with the serial algorithm on CPU. It is shown that the QAM demodulation algorithm gained significant performance increase due to the natural parallism of the GPU, using Compute Unified Device Architecture (CUDA).

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Winholtz, William S., and Lorraine Olson Ramig. "Vocal Tremor Analysis With the Vocal Demodulator." Journal of Speech, Language, and Hearing Research 35, no. 3 (June 1992): 562–73. http://dx.doi.org/10.1044/jshr.3503.562.

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Acoustic analysis of vocal tremor has the potential to make significant quantitative and diagnostic contributions to the study of vocal disorders. This paper presents a new device for analysis of vocal tremor. The Vocal Demodulator produces amplitude- and frequency-demodulated outputs and measures the frequency and level (percent) of low-frequency tremor components in sustained phonation. A standard microphone is used to transduce the voice signal for input to the demodulator. The input fundamental frequency (F o ) range is 70–1200 Hz, and frequency response of the amplitude and frequency demodulation is 2.5–25 Hz. Five parameters are displayed in real time: F o , amplitude-modulation frequency, amplitude-modulation level, frequency-modulation frequency, and frequency-modulation level. Validation, calibration, and reliability data from synthesized test signals with modulation, as well as phonation from subjects with vocal tremor, subjects producing vibrato, and subjects with normal voice are presented. Research and clinical applications of this device are suggested.

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Yang, Zhang Cheng, and Xiang Lin Wang. "Analysis on Anti-Noise Performance of Frequency Modulation System Based on MATLAB Simulation." Applied Mechanics and Materials 543-547 (March 2014): 2426–30. http://dx.doi.org/10.4028/www.scientific.net/amm.543-547.2426.

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The popularity of internet technology has brought the change very big to the life and production of modern humans, the current Internet technology application has penetrated into people in every aspect of modern life, has become an indispensable part of people's life. Firstly, system model of the current network communication to dissect, analyzes the architecture of network communication system, modulation and demodulation principle is applied to design the FM communication signal modulation system network communication in the Internet technology, the non coherent demodulation method to build FM demodulation system, realize the demodulation process through differential device, the anti noise performance of the method of frequency modulation system of MATLAB simulation experiments, the experimental results show that the method of anti noise performance significantly, to a certain extent, provide theoretical basis and technical support for the research in this field.

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Campo-Valera, María, and Ivan Felis. "Underwater Acoustic Communication for The Marine Environment’s Monitoring." Proceedings 42, no. 1 (November 14, 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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Su, Jun, Wei Qing Song, Hong Lin Chen, Xiu Feng Yang, Zheng Rong Tong, and Ye Cao. "A Novel Demodulation Method for Fiber Bragg Grating Sensor System Based on the LabView Software." Advanced Materials Research 403-408 (November 2011): 2364–67. http://dx.doi.org/10.4028/www.scientific.net/amr.403-408.2364.

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The theory of fiber Bragg grating demodulation system based on unbalanced Mach-Zehnder (M-Z) interferometer is introduced. A novel design for demodulation of fiber Bragg grating sensor system based on the LabView Software is proposed and demonstrated. The system is obtained by making use of piezoelectric ceramic (PZT) technology achieving phase carrier modulation. Carrier signal is collected by data acquisition card(DAQ), and the phase modulation of signal is detected by discrete fourier transform(DFT). It realizes real-time demodulation for multiplexed sensing system.

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ZDRAVKOVIĆ, S., M. V. SATARIĆ, and D. VUKOVIĆ. "MODULATION AND DEMODULATION IN DNA MOLECULE." Modern Physics Letters B 20, no. 11 (May 10, 2006): 607–15. http://dx.doi.org/10.1142/s0217984906010706.

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In this paper, we consider the transformation of a breather type soliton in DNA into its demodulated version due to the strong impact of proteins associated with some sequences of DNA chain. These proteins are, for example, RNA polymerase responsible for the formation of m-RNA or initiation protein complex indispensable for chromosome replication.

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Torrance, J. M., and L. Hanzo. "Demodulation level selection in adaptive modulation." Electronics Letters 32, no. 19 (1996): 1751. http://dx.doi.org/10.1049/el:19961225.

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Clark, Marianna, Alan C. Bovik, and Wilson S. Geisler. "Texture segmentation using Gabor modulation/demodulation." Pattern Recognition Letters 6, no. 4 (September 1987): 261–67. http://dx.doi.org/10.1016/0167-8655(87)90086-9.

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Lei, Dong Ming, Ping Li, and Nian Yu Zou. "4PSK Signal Based on FPGA." Advanced Materials Research 694-697 (May 2013): 2870–73. http://dx.doi.org/10.4028/www.scientific.net/amr.694-697.2870.

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Based on the traditional demodulation method of four phase shift keying (QPSK), a QPSK demodulation model was proposed. The FPGA-based QPSK modulation and demodulation system and circuit had been achieved. In Xilinx ISE12.3 development environment, using the SPARTAN-3E development board, the simulation results demonstrate the feasibility of this design.

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Zhang, Kang, Xiaorui Niu, Yunjiao Ma, Xiangmin Chen, Lida Liao, and Jiateng Wu. "A New Demodulation Method for Mechanical Fault Feature Extraction based on LOD and IEE." Measurement Science Review 21, no. 3 (June 1, 2021): 67–75. http://dx.doi.org/10.2478/msr-2021-0010.

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Abstract The rolling bearing and gear fault features are generally shown as modulation characteristics of their vibration signals. The empirical envelope (EE) method is an accordingly common demodulation method. However, the EE method has the defects of over- and undershoot, which may lead to demodulation error. According to this, an envelope optimization algorithm -- empirical optimal envelope (EOE) is introduced into the EE method, and an improved empirical envelope (IEE) method is obtained to calculate the instantaneous amplitude and instantaneous frequency of mono-component modulation signal. Furthermore, aiming at the actual measured mechanical vibration signal has multi-component modulation feature, the IEE method is combined with an adaptive signal decomposition method -- local oscillatory characteristic decomposition (LOD) proposed by the author, thereby a new multi-component signal demodulation method based on LOD and IEE is proposed. The proposed method is compared with Hilbert transform (HT) and Teager energy operator (TEO) demodulation methods by the simulation signal and actual measured mechanical vibration signal. The results show that the demodulation effects including edge effects, negative frequency, over- and undershoot of the proposed method are significantly improved and can extract the rolling bearing and gear fault feature information clearly.

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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 (April 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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Wang, Hao, and Ze Yu Han. "Modulation and Demodulation Techniques in Indoor Visible Light Communication System." Applied Mechanics and Materials 685 (October 2014): 306–9. http://dx.doi.org/10.4028/www.scientific.net/amm.685.306.

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Visible light communication technology is a emerging wireless and optical communication technology developed after invention and application of white LED.In this paper, we have a research based on indoor visible light communication system of lighting white LED,discuss of the visible light communication channel characteristics,detailedly analysis of the indoor visible light communication link. This paper focuses on the modulation and demodulation method applied to visible light communication. In the past visible light communication is mainly used off keying modulation,however, the data transfer speed is limited due to the influence of ISI .This paper presents a solution based on OFDM modulation and demodulation, to reduce the impact brought from inter-symbol string under high data transfer speed.Based on data analysis and computer simulation,the program presented in this paper can be used as indoor lighting and high-speed data transmission.Finally, give scheme to achieve visible light communication modulation and demodulation,provide a theoretical basis for further experiments.

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Rodriguez-Marmolejo, Ulises H., Miguel Mora-Gonzalez, Jesus Muñoz-Maciel, and Tania A. Ramirez-delreal. "FSD-HSO Optimization Algorithm for Closed Fringes Interferogram Demodulation." Mathematical Problems in Engineering 2016 (2016): 1–11. http://dx.doi.org/10.1155/2016/1576735.

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Due to the physical nature of the interference phenomenon, extracting the phase of an interferogram is a known sinusoidal modulation problem. In order to solve this problem, a new hybrid mathematical optimization model for phase extraction is established. The combination of frequency guide sequential demodulation and harmony search optimization algorithms is used for demodulating closed fringes patterns in order to find the phase of interferogram applications. The proposed algorithm is tested in four sets of different synthetic interferograms, finding a range of average relative error in phase reconstructions of 0.14–0.39 rad. For reference, experimental results are compared with the genetic algorithm optimization technique, obtaining a reduction in the error up to 0.1448 rad. Finally, the proposed algorithm is compared with a very known demodulation algorithm, using a real interferogram, obtaining a relative error of 1.561 rad. Results are shown in patterns with complex fringes distribution.

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Chen, Xianqing, and Lenan Wu. "Nonlinear Demodulation and Channel Coding in EBPSK Scheme." Scientific World Journal 2012 (2012): 1–7. http://dx.doi.org/10.1100/2012/180469.

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The extended binary phase shift keying (EBPSK) is an efficient modulation technique, and a special impacting filter (SIF) is used in its demodulator to improve the bit error rate (BER) performance. However, the conventional threshold decision cannot achieve the optimum performance, and the SIF brings more difficulty in obtaining the posterior probability for LDPC decoding. In this paper, we concentrate not only on reducing the BER of demodulation, but also on providing accurate posterior probability estimates (PPEs). A new approach for the nonlinear demodulation based on the support vector machine (SVM) classifier is introduced. The SVM method which selects only a few sampling points from the filter output was used for getting PPEs. The simulation results show that the accurate posterior probability can be obtained with this method and the BER performance can be improved significantly by applying LDPC codes. Moreover, we analyzed the effect of getting the posterior probability with different methods and different sampling rates. We show that there are more advantages of the SVM method under bad condition and it is less sensitive to the sampling rate than other methods. Thus, SVM is an effective method for EBPSK demodulation and getting posterior probability for LDPC decoding.

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Yang, Chaozhong, Yulin Wang, Shifeng Li, and Wenhe Yan. "Experimental Study of a Signal Modulation Method to Improve eLORAN Data Channel Communications." Sensors 20, no. 22 (November 14, 2020): 6504. http://dx.doi.org/10.3390/s20226504.

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There are mainly two types of data modulation methods used for enhanced LOng-RAnge Navigation (eLORAN) systems: pulse position modulation (PPM) and supernumerary interpulse modulation (SIM). The typical application for PPM is tri-state PPM (3S-PPM), also known as Eurofix. The typical application for SIM is ninth pulse modulation. Both of these methods are phase modulation methods. Phase modulation coding, a very mature technology, is used at present. To achieve a better demodulation success rate of eLORAN digital modulation signals at longer distances, a method of using the transmitting station duplex mode to transmit a digital modulation pulse group after LORAN-C transmitting a pulse group is proposed to realize modulation pulse on–off modulation. In this method, a broadcasting experiment was performed on the BPL (The call sign of eLORAN time service system in China) broadcaster station. After monitoring, a good receiving demodulation effect was initially obtained.

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Jin, Tao, Ping Xian Yang, and Zhen Bao Liu. "Design of Power Line Communication System Underground Based on Zigbee in Electrical Control Engineering." Advanced Materials Research 676 (March 2013): 193–98. http://dx.doi.org/10.4028/www.scientific.net/amr.676.193.

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Abstract. It is introduced that the complementary advantages between Zigbee and PLC underground in Electrical Control Engineering, improving effectively the reliability and stability of transmission of PLC. Not only is the principle diagram of the design given, also a design of OFDM modulation and demodulation from the signal of Zigbee is realized based on FPGA. The program and simulation is designed for OFDM modulation and demodulation with ISE10.1. It is improved feasible with the data of experiences.

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Roy, Arijit, Harshal B. Nemade, Ratnajit Bhattacharjee, and Vinod Kushwah. "DQPSK modulation and demodulation using SAW device." IET Communications 11, no. 17 (November 30, 2017): 2630–36. http://dx.doi.org/10.1049/iet-com.2017.0821.

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Zhang, Rui, Jiandong Li, and Jie Wu. "A universal algorithm of modulation and demodulation." Journal of Electronics (China) 19, no. 3 (July 2002): 289–95. http://dx.doi.org/10.1007/s11767-002-0052-9.

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Jang, In-Gyu, Sung-Hyun Lee, and Yong-Hwa Park. "A Parallel-Phase Demodulation-Based Distance-Measurement Method Using Dual-Frequency Modulation." Applied Sciences 10, no. 1 (December 31, 2019): 293. http://dx.doi.org/10.3390/app10010293.

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Time-of-flight (ToF) measurement technology based on the amplitude-modulated continuous-wave (AMCW) model has emerged as a state-of-the-art distance-measurement method for various engineering applications. However, many of the ToF cameras employing the AMCW process phase demodulation sequentially, which requires time latency for a single distance measurement. This can result in significant distance errors, especially in non-static environments (e.g., robots and vehicles) such as those containing objects moving relatively to the sensors. To reduce the measurement time required for a distance measurement, this paper proposes a novel, parallel-phase demodulation method. The proposed method processes phase demodulation of signal in parallel rather than sequentially. Based on the parallel phase demodulation, 2π ambiguity problem is also solved in this work by adopting dual frequency modulation to increase the maximum range while maintaining the accuracy. The performance of proposed method was verified through distance measurements under various conditions. The improved distance measurement accuracy was demonstrated throughout an extended measurement range (1–10 m).

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Fu, Gang, Yan Jun Wu, Ren Long Li, and Li Ping Wang. "Research on FM Telemetry Software Demodulation Algorithms." Advanced Materials Research 989-994 (July 2014): 3938–41. http://dx.doi.org/10.4028/www.scientific.net/amr.989-994.3938.

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Aimed at the problem that the demodulation threshold of non-coherent demodulation technology of PCM/FM telemetry system using frequency modulation in the present situation of aerospace measurement and control is higher, research a kind of multiple symbol detection based on maximum likelihood thought (Multi-Symbol Detection, MSD) demodulation method. This paper introduces the principle of multiple symbol detection and aiming at the shortcomings of the previous synchronization method, studies a kind of symbol decision process and synchronization of the combination of synchronization method.

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R. Udawant, Sandip, and Satyawati Magar. "Modulation and Demodulation of Image Processing by Using GMSK." International Journal of Engineering & Technology 7, no. 3.27 (August 15, 2018): 233. http://dx.doi.org/10.14419/ijet.v7i3.27.17883.

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Today digital communication is widely used in telecommunication sector in which the information is coded in the form of bits. There are many techniques that are implemented for modulation in digital communication some of them are BPSK, QPSK, M-ary PSK, GMSK. While transmitting an image there is always a challenge to retain the quality of an image by using these digital modulation techniques. In this paper GMSK technique is used for transmitting an image. The GMSK modulation technique is widely used in GSM techniques. By using GMSK modulation technique, which carries the information with high data rate and this is very important for image transmission. The proposed system gives better results than other modulation techniques like BPSK and M-ary PSK.

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Cobb, W. Tyler, and Linda B. McGown. "Multifrequency Phase-Modulation Fluorescence Lifetime Determinations On-the-Fly in HPLC." Applied Spectroscopy 43, no. 8 (November 1989): 1363–67. http://dx.doi.org/10.1366/0003702894204317.

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The first use of a multifrequency, phase-modulation spectrofluorometer for fluorescence lifetime determinations on-the-fly in HPLC is described. Direct, simultaneous measurements of fluorescence intensity, phase-shift, and demodulation are made at one-second intervals for polycylic aromatic hydrocarbons as they are eluted from the chromatograph. Fluorescence lifetime is calculated from both the phase-shift and the demodulation; the two independent values can be used to indicate the absence or presence of more than one component at any point in the chromatogram. Special considerations regarding data correction and calibration for phase-modulation lifetime determinations under continuous-flow conditions are discussed, along with effects of flow rate and mobile phase composition.

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Al-Rawi, Muhanned. "Data-Aided Carrier Recovery with QPSK Modulation." Scientific Bulletin 24, no. 1 (June 1, 2019): 14–22. http://dx.doi.org/10.2478/bsaft-2019-0002.

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Abstract Digital communication has proven to be the most efficient method of data transmission especially where long distances are involved. This led to the invention of more sophisticated methods of communication ranging from mobile handset communication to more advanced satellite communication. The speeds of passing information have been improving over the years and real time video communication has been made possible with digital devices. Various methods of digital data transmission are employed based on the information to be transmitted. This paper focuses on carrier recovery in digital communication systems, especially those based on Quadrature Phase Shift Keying (QPSK) modulation and demodulation scheme. The design being implemented is that of coherent demodulation for QPSK scheme using SIMULINK design tool. Performance of QPSK is also investigated to make a comparison and the suitability of the scheme to use in digital data transmission applications.

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Shen, Wei, and Biyang Wen. "A New Demodulation and Modulation Method Designed for FMCW Radar." Journal of Electrical and Computer Engineering 2010 (2010): 1–6. http://dx.doi.org/10.1155/2010/897429.

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An efficient demodulation method designed for FMCW (Frequency-Modulated Continuous Wave) radar is presented. It is a kind of modified DFT (IDFT) algorithm; the spectrum segment of interest can be easily extracted from the original signal without calculating the whole DFT/FFT. It provides fast demodulation and extraction of desired frequency bands in our HFSWR (High-Frequency Surface Wave Radar) system. The proposed approach enhances the performances of radar system and reduces the computing complexity. The new structure could also be inversely used for signal modulation. And also arbitrary sampling rate conversion could be achieved with the combination of forward and backward structure.

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Luo, Songrong, Junsheng Cheng, and Jianping Fu. "Application of Self-Adaptive Wavelet Ridge Demodulation Method Based on LCD to Incipient Fault Diagnosis." Shock and Vibration 2015 (2015): 1–13. http://dx.doi.org/10.1155/2015/735853.

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When a local defect occurs in gearbox, the vibration signals present as the form of multicomponent amplitude modulation and frequency modulation (AM-FM). Demodulation analysis is an effective way for this kind of signal. A self-adaptive wavelet ridge demodulation method based on LCD is proposed in this paper. Firstly, multicomponent AM-FM signal is decomposed into series of intrinsic scale components (ISCs) and the special intrinsic scale component is selected in order to decrease the lower frequency background noise. Secondly, the genetic algorithm is employed to optimize wavelet parameters according to the inherent characteristics of signal; thirdly, self-adaptive wavelet ridge demodulation wavelet for the selected ISC component is performed to get instantaneous amplitude (IA) or instantaneous frequency (IF). Lastly, the characteristics frequency can be obtained to identify the working state or failure information from its spectrum. By two simulation signals, the proposed method was compared with various existing demodulation methods; the simulation results show that it has higher accuracy and higher noise tolerant performance than others. Furthermore, the proposed method was applied to incipient fault diagnosis for gearbox and the results show that it is simple and effective.

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LANG Jin-peng, 郎金鹏, 常天英 CHANG Tian-ying, 陈建冬 CHEN Jian-dong, 刘野 LIU Ye, 崔洪亮 CUI Hong-liang, and 于淼 YU Miao. "Improved Phase Generated Carrier Modulation and Demodulation Method." ACTA PHOTONICA SINICA 45, no. 12 (2016): 1207004. http://dx.doi.org/10.3788/gzxb20164512.1207004.

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Li, Ke, Chunping Hou, Yonghong Hou, and Jinlin Fu. "New cooperative frequency domain differential modulation and demodulation." Journal of Systems Engineering and Electronics 22, no. 6 (December 2011): 892–96. http://dx.doi.org/10.3969/j.issn.1004-4132.2011.06.003.

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Batenkov, K. A. "Stability threshold of modulation and demodulation linear methods." Infokommunikacionnye tehnologii 14, no. 1 (March 2016): 39–46. http://dx.doi.org/10.18469/ikt.2016.14.1.05.

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胡, 冰冰. "Demodulation for Bipolar Pulse Modulation under Pulse Interference." Hans Journal of Wireless Communications 07, no. 01 (2017): 17–22. http://dx.doi.org/10.12677/hjwc.2017.71003.

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del Toro Iniesta, Jose Carlos, and Manuel Collados. "Optimum modulation and demodulation matrices for solar polarimetry." Applied Optics 39, no. 10 (April 1, 2000): 1637. http://dx.doi.org/10.1364/ao.39.001637.

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Journal articles on the topic 'Modulation and Demodulation'

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