scholarly journals Intrinsic Signal Processed Non-Linearity Tolerant Novel 2-Tier Star Constellation

Author(s):  
zahid khaki ◽  
Gausia Qazi

Abstract In coherent optical systems, optical fiber non-linearity is a consistent limiting factor towards the effective signal-to-noise ratio though being mitigated by various digital signal processing based approaches. In this paper, an intrinsic method of signal processing based on the shape of the input constellation is employed to yield a novel non-linearity tolerant geometric constellation. 16-QAM back-to-back coherent system is optimized for minimum value of non-linear interference, and a novel 2-tier star constellation using sequential quadratic programming algorithm is proposed. The values of second and fourth order moments of input obtained for the optimized 2-tier star constellation are 1.19 and 1.70 respectively, resulting in an overall reduction of non-linear interference.

2011 ◽  
Vol 383-390 ◽  
pp. 471-475
Author(s):  
Yong Bin Hong ◽  
Cheng Fa Xu ◽  
Mei Guo Gao ◽  
Li Zhi Zhao

A radar signal processing system characterizing high instantaneous dynamic range and low system latency is designed based on a specifically developed signal processing platform. Instantaneous dynamic range loss is a critical problem when digital signal processing is performed on fixed-point FPGAs. In this paper, the problem is well resolved by increasing the wordlength according to signal-to-noise ratio (SNR) gain of the algorithms through the data path. The distinctive software structure featuring parallel pipelined processing and “data flow drive” reduces the system latency to one coherent processing interval (CPI), which significantly improves the maximum tracking angular velocity of the monopulse tracking radar. Additionally, some important electronic counter-countermeasures (ECCM) are incorporated into this signal processing system.


1994 ◽  
Vol 19 (2) ◽  
pp. 144 ◽  
Author(s):  
Haris Riris ◽  
Clinton B. Carlisle ◽  
Russell E. Warren ◽  
David E. Cooper

Author(s):  
V.F. Telezhkin ◽  
◽  
B.B. Saidov ◽  
P.А. Ugarov ◽  
A.N. Ragozin ◽  
...  

In the present work, processing of an electro cardio signal using a wavelet transform is consi-dered. In electrocardiography, various digital signal-processing techniques are used to detect, extract, and analyze the various components of an electrocardiogram. Among them, the wavelet transform technique gives promising results in the analysis of the time-frequency characteristics of the electrocardiogram components. The urgency of solving the problem of improving the quality of life of people with the help of early diagnosis and timely treatment of various cardiac diseases is obvious. The process of automated analysis of a huge database of electrocardiographic data is especially important. Wavelet analysis can be successfully used to smooth and remove noise in the ECG signal. Electrocardiogram signal, cleaned from noise components, looks clearer, while its volume is from 10 to 5% of the original signal, which largely solves the problem of storing cardiac records. Aim. Development of an algorithm for threshold processing of wavelet coefficients and filtering of an electrocardiography signal. Materials and methods. Cardiograms were taken for analysis. Then they were digitized and entered into a computer for processing. A program was written in the MATLAB environment that implements continuous and discrete wavelet transform. Results. The work shows the result of filtering the ECG signal with the addition of noise with a signal-to-noise ratio of 35 and 45 dB using the decomposition levels N = 2, N = 3, N = 4. Conclusion. Based on the analysis of the data obtained, it can be concluded that the second level of decomposition is the most optimal for filtering the ECG signal. With an increase in the level of decomposition, the output ratio decreases, at the level N = 4 the output signal-to-noise almost does not exceed the input one, therefore, the filtering becomes ineffective. The correlation coefficient to the fourth level is significantly reduced, which means a significant increase in the distortion introduced by the filtering algorithm.


Author(s):  
Mohd Israil

Challenges in high speed data transmission technology over time varying fading channels is addressed in this paper. More precisely, the signal processing at the receiver side has to be analyzed for such systems, as it is well known that the mobile radio channels are characterized by frequency selective fast fading is typically introduced error in the received signal. Thus, the performance of the receiver severely degraded because of such factors. Specifically, this paper deals with the detection using a matched filter followed by low weight near maximum likelihood detector (NMLD) for the application of digital signal processing in outdoor vehicular radio environments. Nearly Maximum Likelihood Detection depends on the length of the stored vectors as well as depends on the numbers of the stored vector. In [1] complexity is reduced by reducing the stored vectors, in this paper same NMLD used but the complexity of the matched filter is reduced by some variance. Finally, the bit error rate (BER) is measured with signal to noise ratio.


2021 ◽  
pp. 89-94
Author(s):  
I. A. Ershov ◽  

The article deals with signal processing of a fiber-optic temperature sensor using extremal filtering and filtering with Wavelet transforms. The aim of this work is to find a way to reduce the response time in a fiber-optic temperature sensor by using effective signal processing methods. Reducing the response time of systems for monitoring hazardous production facilities is rarely discussed in the literature. The results showed that the use of extreme filtering and filtering with Wavelet transforms can significantly reduce the number of implementations necessary to identify a signal with a low signal-to-noise ratio


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