Design And Optimization Of VOIP Voice Terminal Based On Power Communication System

With the applacation of VOIP technology in the power system,Band width resource was efficiently used,and reuse the net resource inside the power system.but terrible speech quality is the weakness of this technology in case of low SNR,so it is significative that develop the study of design and optimizing of VOIP in power system.The text did research into voice noise of speech communication in transformer substation in view of voice enhancement algorithm,voice enhancement by the combination of spectral subtraction and voice endpoint detection was achieved in case of low SNR,and VOIP system,IP voice terminal and Web were designed.the text's suggested algorithm was applied to the IP voice terminal.this text's content as follows:(1)For the spectral subtraction's terrible performance in low SNR,the method of self-adapting spectral subtraction based on energy threshold value was suggested.which can be use to filter and detect for voice signal in low SNR,voice signal's energy was rasied by researching in 0dn,1db,2db,3db four kinds of SNR conditions,the text came true a increase of SNR value by introducing energy threshold value,if the value of filtered voice greater than energy threshold,the basic spectral subtraction will continue to execute.the the increase of SNR value was accomplished.(2)For the voice's endpoint detection's inaccurate question in low SNR,the method of combination of Teager energy and EMD was suggested.First of all,the voice with a noise were filtered preliminarily,then function of IMF were obtained,EMD's resolving was executed,according to the character of sensitivity to frequency modulation signal amplitude modulation signal of Teager operator.the energy value of IMF by Teager operator was calculated,and then the energy value of IMF was added.the new energy value was used to replace the traditional short-time energy value for voice endpoint detection.and got a more accurate endpoint detection result.(3)For the method of some transformer substation's communication scheduling,VOIP system was set up,soft and hardware was based on Internet Protocol in client-side,the feasibility of proposed algorithm was tested.Web was designed in server-side.concentrated management was accomplished.