Non-cooperation Shortwave Frequency Hopping Signal Fine Stitching Technology Research - The Frequency Difference Analysis And Adjustment Of Hardware And Software Design

The reconnaissance and processing of the non-cooperative frequency hopped signal in short-wave band includes signal-linterception, de-interleaving, align of carrier frequencies, modulation recognition and demodulation, then can resume original information. In which, align of carrier frequencies divides into two steps to be completed: the general allign and the fine align. This paper highlights the technique of implementing the fine align on the foundation of the general align.So-called fine align denotes: Adjust the carrier frequencies of all the signal intervals and make them approximately equal. After the general align, the carrier frequencies difference of all intervals are still big, can't reach the overall requirement of systematic design and must be further processed, the fine align. This paper has discussed in detail many problem that implements fine align using high-speed DSP to consider.To achieve the fine align , follow three stages: First stage is power spectrum calculation; Second stage is the analysis of frequency difference, which calculates the carrire frequencies difference between adjacent signal intervals; The stage of 3th is frequency adjustment. The analysis of frequency difference is to complete the calculation of the information of frequency difference using the power spectra of adjacent interval that first stage produces. Then with this information, in the stage of 3th, the carrier frequencies of all hopped signal intervals will adjust to the scope of requirement.The major work that this paper is concerned with includes:1. According to emulatation result and theory estimate, we have made the algorithm of the analysis of frequency difference and frequency adjustment.2. Software and hardware design of the analysis of frequency difference and frequency adjustment.3. Systematic test.In the specific course of realizing , the analysis of frequency difference andfrequency adjustment are completed each with one TMS320C50 , in which the key of the analysis of frequency difference is correlation, and frequency adjustment is completed through freauency down conversion. Usually , the frequency down conversion needs the chip for special purpose of expensive price. This paper have made the scheme to be implemented with high-speed DSP of low costing as lower speed. Thtough test , it is basically feasible to have verified this scheme.