Phase-Inversion Symmetric Method Application In Airspace Domian And The Anti-Noise Performance

As we know,the noise in channel is presumed as Gaussian white noise in classical communication theory,but in actual wireless communication system, on the one hand the power of man-made noise with strong correlation far exceeds natural noise and on the other hand band width in factual communication is limited. Exactly speaking, band width in communication is narrowband and Gaussian white noise is also have correlation on occasion of bandwidth limited. And the distribution of man-made noise whith possess very strong correlation is not Gussian. Therefore, prodigious error will bring on using method of classical theory to analyze modern communication system. Along with our theoretical investigation of antiphase balanced method ( Phase - Inversion Symmetric Method,PISM),PISM certainly exert huge action at physical communication. Antiphase balanced method eliminate noise using band limit noise and numerical characteristics,and it can abstract weak signal from very strong noisy and enhance SNR. First of all,the thesis analyze different kinds of noise in communication system, present method to test noise correlation, and verify that man-made noise impacting communication quality mostly is very correlation in modern wireless communication environment. Such correlation can be utilized to improve output signal-noise ratio of the system. Secondly,basic principles of antiphase balanced method is introduced, mechanism of band limit noise utilized by PISM and correlation of numerical characteristics is illuminated, the relationship of PISM, shannon equation and shannons theorem is explicited.At foundation of theoretical analysis before, application of PISM at frequency domain and double-side-band communication system is introduced and proceeded emulation and analyze with speciality digital simulation software SYSTEMVIEW. Application feasibility of PISM at frequency domain and PISM - DSB is verified in many further more. Then, application at airspace of PISM is innovatively brought forward and application model of airspace PISM is established. Channel in apace is divided in to divers subchannel and the space of neighbour subchannel will be small. In addition, oscillograph test proves that nearer in space, stronger of noise correlation, so inverter round robin is seted at neighbour subchannel, noise can be eliminated according to hoarse correlation and enhance SNR of output signal. Theoretical derivation of application at airspace of PISM is proceeded in the thesis,and yield that SNR gain of output signal is related to correlation coefficient of noise and not related to SNR of incoming signal .In addition , feasibility of PISM at airspace is proved. Noise figure of noise in frequency domain and airspace is tested, test result proves that noise correlation is stronger with nearer and narrower of waveband, at the same time,test result also proves that nearer in space,noise correlation stronger.Last, task of the theses is summarized and research orientation in next step. Emphases is combine PISM with physical item and apply PISM to practice.