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Fundamentals of Quadrature Amplitude Modulation
1995Quadrature amplitude modulation (QAM) is a widely used method for transmitting digital data over bandpass channels. It can be viewed as a generalization of PAM to bandpass channels. All current telephone line modems based on the ITU-T V series recommendations for transmission at rates of 2400 bps or more use QAM or include it as an option.
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Quadrature amplitude modulation (QAM) using binary-driven coupling-modulated rings
Optics Communications, 2016Abstract We propose and fully analyze a compact structure for DAC-free pure optical QAM modulation. The proposed structure is the first ring resonator-based DAC-free QAM modulator reported in the literature, to the best of our knowledge. The device consists of two segmented add-drop Mach Zehnder interferometer-assisted ring modulators (MZIARM) in an ...
Samira Karimelahi, Ali Sheikholeslami
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Spatially inhomogeneous phase-modulating interferometry by non-quadrature amplitude modulation
SPIE Proceedings, 2013A new method to generate inhomogeneous spatial phase variation and phase retrieval is proposed. This method is based under the scheme of three beams forming two Mach-Zehnder interferometers in series, where one arm is considered as the probe beam, while the other two will compose the reference beam where a phase difference within the range of (0,π ) is
U. Rivera-Ortega +2 more
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Costas Loop for Quadrature Amplitude Modulation
2017A Costas loop for the reception of Quadrature Amplitude Modulation (QAM) signals is presented in this chapter. The generation of the QAM signal is described first. When the data signals (I and Q in this case) are unfiltered, the modulated QAM signal would occupy a large frequency range. To reduce bandwidth, the I and Q signals are usually filtered.
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Transmission System with Quadrature Amplitude Modulation
2018This chapter presents an overview on the principles of digital communications. We focus on a system with one transmitter and one receiver, i.e., for a channel with a single input single output (SISO). This will also provide the necessary basics for multiple input multiple output (MIMO) systems investigated in Part III.
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Bitwise Log-Likelihood Ratios for Quadrature Amplitude Modulations
IEEE Communications Letters, 2015For an increase in spectral efficiency and improvement of error performance, a high-order modulation and an advanced channel coding scheme are jointly used for many digital communication systems. In this paper, a new and simple method for calculating bitwise log-likelihood ratios which are required for soft decision decoding is proposed for $M ...
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Integrative oncology: Addressing the global challenges of cancer prevention and treatment
Ca-A Cancer Journal for Clinicians, 2022Jun J Mao,, Msce +2 more
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