The Detection And Recognition Of HF Morse Signal

The purpose of this thesis is in order to achieve HF Morse signal detection and the automatic decoding of Morse code.Morse signal will have noise interference inevitably in the process of HF channel transmission.Because of the noise has greatly harmed to human body.This posed a challenge for Army,government agencies,and radio operators and other personnel engaged in Morse code copy.It increases the Labor intensity of copy personnel,especially for that long time engaged in HF Morse copy work.It will have great influence on its sense of hearing.If we can use modern science and technology,to make the Morse code can be automatically copy,not only can reduce labor intensity of copy personnel,reduce noise pollution damage to the work environment,and can improve the efficiency of code copy.Reduce resource waste effectively.This thesis introduced firstly common on the market the working principle of HF digitized receiver.And then analyzed in detail a type of receiver working principle,system structure,the electrical parameters and the technical indicators to used in the practical work.The HF digital receiver after added option of standard signal generator and the frequency doubling preselector,reception performance be increased greatly,suitable for receiving HF Morse signal.In terms of HF Morse signal noising,according to the characteristics of the Morse signal,put forward the improvement of the Morse signal denoising algorithm based on wavelet transform,wavelet packets noise reduction.Using Morse signal wavelet packet decomposition,through to make proper adjustment of the threshold estimation algorithm,on the basis of the original threshold estimation,dynamic weighted,enhanced the adaptive of the threshold estimation algorithm,thus improving the effect of reducing noise.In Morse signal detection and Morse code recognition,the main use of the speech recognition technology,for audio data after the noise reduction of audio data samples,A/D transformation,Morse signal detection,Morse code rate real-time measurement,to obtain the Morse code input vector binary tree to query,and complete the decoding based on the decoding notebook.Through the experimental simulation and the real application,to verify the effectiveness of wavelet transform is used to remove the Morse signal noise and using the voice technology tocomplete the decoding.