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Analyzing image transmission quality using filter and C-QAM
Published in Debatosh Guha, Badal Chakraborty, Himadri Sekhar Dutta, Computer, Communication and Electrical Technology, 2017
Md. Khaliluzzaman, Deepak Kumar Chy, Kaushik Deb
This section uses the root raised cosine filter to eliminate inter-symbol interference, which degrades the image quality severely at low signal-to-noise ratio. Single raised cosine filter at transmitter side cannot reduce the inter-symbol interference. Therefore, a pair of raised cosine filters is used in this paper, which acts as root raised cosine filter. In addition, the original image block is in frequency domain, but raised cosine filter and AWGN model follow real-time operation. For this purpose, Inverse First Fourier Transform (IFFT) is introduced in this proposed method before using raised cosine filter.
Stair-type parallel digital predistorter for power amplifier linearisation and harmonic reduction
Published in International Journal of Electronics Letters, 2021
Eui-Rim Jeong, Hyukjun Oh, Jingon Joung
The proposed PD was initially examined through computer simulation. In the simulation, the transmitted signals were modulated using 16-quadrature amplitude modulation (16-QAM), and pulse-shaped using a square-root-raised-cosine filter with a roll-off factor of 0.25. The pulse-shaping filter output was oversampled ten times. We assumed to remove harmonics up to the third. Further interpolation of the PD output was performed by a factor of 20 to model the analog up/down-converter and analog PA in the digital domain. The carrier frequency was , where is the symbol rate. Fifth-order polynomials were used for the PA models:
Frequency selective digital predistortion for harmonic rejection
Published in International Journal of Electronics, 2018
Xiaofang Wu, Xinshuo Cai, Jinfu Huang, Jianghong Shi
First, the performance of our proposed DPD method is examined through simulation. The transmitted signal is a 16-quadrature amplitude modulation signal which is pulse-shaped by a square root raised cosine filter with roll-off 0.25. The sampling clock of pulse shaping filter output is 10 times the symbol rate. The coefficients of PA model inEquation (1) are setting as as in Choi et al. (2011) which is extracted from a real solid-state PA. The carrier frequency is , where is the symbol rate.