Results 291 to 300 of about 130,433 (340)

NTF-Improved Delta-Sigma Modulation Supported 65536 QAM Signal for Mobile Fronthaul

Journal of Lightwave Technology
In this article, a support 65536 QAM signal mobile fronthaul (MFH) architecture based on the noise transfer function (NTF)-improved delta-sigma modulation (DSM) was proposed and demonstrated by experiment. In the NTF-improved DSM, the extended Lee's rule
Xiongwei Yang, Jianjun Yu, Xianmin Zhao, Yi Wei, F. Zhao, Wen Zhou, Kaihui Wang   +6 more
semanticscholar   +1 more source

Optimization for sigma-delta modulators

Proceedings of 13th International Conference on Digital Signal Processing, 2002
The performance of a higher-order single-stage sigma-delta modulator (/spl Sigma//spl Delta/M) is determined by the loop filter in which the quantizer is embedded. Not the coefficients in the loop filter themselves, but ratios of them determine the input-output relationship in the modulator and thus its performance.
A. Pneumatikakis, A. Constantinides, V. Anastassopoulos, T. Deliyannis   +3 more
openaire   +1 more source

4096-QAM Signal Transmission by an IM/DD System at THz Band Using Delta-Sigma Modulation

IEEE Photonics Technology Letters
The transmission of high-order quadrature amplitude modulation (QAM) signals in a low-cost intensity-modulated direct detection (IM/DD) THz-band communication system at 300 GHz is experimentally demonstrated in this letter. The system employs delta-sigma
Jingwen Tan, Jianyu Long, Jianjun Yu, Xiongwei Yang, Jiaxuan Liu, Peng Tian, Sicong Xu, Yang Han, Bing Zhang, Yao Zhang   +9 more
semanticscholar   +1 more source

Analysis of Sigma Delta Modulators

1989
Sigma delta modulators are used for high performance analogue to digital conversion. Here an introduction to the analysis and properties of these devices is considered.
C. P. Lewis, C. M. Gordon
openaire   +1 more source

Two-stage sigma-delta modulation

IEEE Transactions on Acoustics, Speech, and Signal Processing, 1990
An exact analysis of the nonlinear difference equation describing a discrete time two-stage sigma-delta quantizer with DC and sinusoidal inputs is presented. It is shown that for DC inputs, the binary quantizer error of the second quantizer, which appears at the output of the modulator as a second-order difference, is asymptotically white, uniformly ...
P.W. Wong, R.M. Gray
openaire   +1 more source

SNR enhanced OAM mode division multiplexing with in-band noise modulation based on cascade delta-sigma modulation.

Optics Express
Due to mode coupling, a high signal-to-noise ratio (SNR) is required in orbital angular momentum (OAM) modular division multiplexing (MDM) systems to improve transmission performance.
Sihan Wang, Fei Wang, Ran Gao, Dong Guo, Huan Chang, Zhipei Li, Xiaolong Pan, Sitong Zhou, Qi Zhang, Xiangjun Xin   +9 more
semanticscholar   +1 more source

Secure transmission in a W-band RoF system based on delta-sigma modulation.

Optics Letters
In this Letter, a delta-sigma modulation (DSM) encryption technique in a W-band RoF system is proposed. By performing DSM with different over-sample ratios (OSRs) on the OFDM signal based on the controlled keys generated by the chaotic system at the ...
Yaoqiang Xiao, Chunxi Zhou, Linrong Jiang, Zhaoyu An, Yuqing Li   +4 more
semanticscholar   +1 more source

Dithering and its effects on sigma-delta and multistage sigma-delta modulation

IEEE Transactions on Information Theory, 1991
The spectrum of the quantization error in a dithered sigma-delta modulator is derived under the constraint that the dithering signal does not cause overload. The results apply to DC, sinusoidal, and more general quasi-stationary signals. It is shown in the case of a simple sigma-delta modulation that no-overload dithering can smooth the error spectrum ...
W. Chou, R.M. Gray
openaire   +1 more source

Pulse-width modulation in sigma-delta modulators

Proceedings of 2010 IEEE International Symposium on Circuits and Systems, 2010
Time-encoding machines map analog or multi-bit digital signals to a binary stream. The information contained in the input signal is preserved by the high resolution achieved in the time domain. Pulse-Width Modulators (PWMs) rely on a similar operation principle.
F. Colodro, A. Torralba
openaire   +1 more source

Pruned Tree Sigma-Delta Modulation

2011
The Pruned Tree sigma-delta modulation algorithm is a further refinement on the algorithms that are described in the previous chapters. This algorithm is a practical realization of the pruned look-ahead approach as derived in chapter six. A total of M paths are tracked, with no constraints on the solution space coverage imposed.
Janssen, Erwin, van Roermund, Arthur
openaire   +2 more sources