Modulation identification of digital signals by the wavelet transform

2000 ◽  
Vol 147 (4) ◽  
pp. 169 ◽  
Author(s):  
K.C. Ho ◽  
W. Prokopiw ◽  
Y.T. Chan
Author(s):  
Dr Sattar B. Sadkhan ◽  
Dr Nidaa A. Abbas ◽  
Members ◽  
IEEE

2008 ◽  
Vol 2008 ◽  
pp. 1-8 ◽  
Author(s):  
P. Prakasam ◽  
M. Madheswaran

A generalized modulation identification scheme is developed and presented. With the help of this scheme, the automatic modulation classification and recognition of wireless communication signals with a priori unknown parameters are possible effectively. The special features of the procedure are the possibility to adapt it dynamically to nearly all modulation types, and the capability to identify. The developed scheme based on wavelet transform and statistical parameters has been used to identify M-ary PSK, M-ary QAM, GMSK, and M-ary FSK modulations. The simulated results show that the correct modulation identification is possible to a lower bound of 5 dB. The identification percentage has been analyzed based on the confusion matrix. When SNR is above 5 dB, the probability of detection of the proposed system is more than 0.968. The performance of the proposed scheme has been compared with existing methods and found it will identify all digital modulation schemes with low SNR.


2021 ◽  
Vol 15 (4) ◽  
pp. 483-490
Author(s):  
Zeynab Mohabati ◽  
Maryam Khoddam

With proliferation of power grids, different types of faults are more likely to occur. The purpose of system protection relays is to detect abnormal signals that indicate faults in the transmission system and to separate the fault section from the rest of the system to prevent the fault from propagating to other parts of the system. Proliferation of electronic devices led to creation of digital relays made of microprocessors. Hence, analog measurements are converted into digital signals for processing by microprocessors. Air grids are more likely to cause faults than other components of the power system; thus, disturbances affecting the system must be detected quickly and accurately. Therefore, the problem of fault detection and classification is an important factor for economic exploitation of the power grid. Accurate fault handling results in faster repair operations, better system availability, lower operating costs and timesavings. The proposed design in this study was based on detecting the type of fault caused in transmission lines. In order to improve the condition of the relays in the transmission grid, analysis of the signals reached to the relay on both sides of the line was used to detect the fault and its type. The main purpose was to quickly detect the type of fault using wavelet transform. For this purpose, the signal was sampled after the fault occurs and the feature signal was extracted after analysis by wavelet transform. These features were included in the decision tree classifier and the type of the fault was decided.


2014 ◽  
Vol 1014 ◽  
pp. 413-416 ◽  
Author(s):  
Shu Mei Yan ◽  
Hui Fang

Large errors in the digital signal modulation recognition algorithm for the general wavelet transform, we propose a discrete optimization algorithm based on wavelet transform, which is generally improved algorithm based on wavelet transform algorithm, the original algorithm in order to avoid redundancy Yu phenomenon, discrete variable domain transform operation, the wavelet transform and then use the algorithm to improve the amplitude modulation of digital signals, quadrature amplitude modulated signal, a digital frequency-modulated signal and the digital phase modulated signal is identified. Simulation results show that the discrete wavelet transform algorithm optimization wavelet transform algorithm than the digital signal modulation recognition applications to identify errors in the proposed smaller, more accuracy.


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