The Realization Of Network Communications And The Implementations Of Algorithms On Dsp In The Spectrum Monitoring Receiver

With the rapid development of radio business, distribution and management of spectrum resources are becoming increasingly important. It is of important practical value and realistic meaning to study a new spectrum monitoring receiver. Locating the disturbance sources in time is also one of the most important functions of monitoring receiver because of multiple sites to monitor. TDOA(time difference of arrival) location technology is ofen used in the monitoring receiver and the method of time delay estimation is an important and key part of the TDOA location. Thus, the implementation of time delay estimation algorithm on DSP is also discussed in this dissertation.This dissertation is focused on the multiple-client server, the realization of network communications and the implementations of time delay estimation algorithms on DSP in the spectrum monitoring receiver.First of all, this dissertation introduces the whole architecture of the monitoring receiver and points out the function of the DSP module in the whole system. Then the design of multiple-tasking system architecture of the OMAPL138 module and the advantages of this dual core chip are presented. According the dual core architecture of OMAPL138, this dissertation divides the tasks on DSP module into two parts. The network communication module and rights management module are implemented by the ARM core of OMAPL138 and the communiation with FPGA and digital signal processing algorithms are completed by the DSP core. The communication of two cores is implemented by the DSPLink driver. This dissertation also designs a multiple-client server for radio management to monitor the spectrum resources more conveniently. The client software uses encrypted packets to log on the server in the receiver and can add typical users easily, which meets the demands of users.Secondly, three time delay estimation algorithms are implemented on the DSP core.Integer time delay interpolation algorithm is firstly implemented by using FFT method.Both fix-point and floating-point implementation of fractional interpolation algorithm are completed because the C6748 core can support both fix-point and floating-point operations. This dissertation introduces a new time delay algorithm based on FIR filter and compares the realization of this algorithm with the interpolation algorithm on DSP.For varying time delay, this dissertation introduces an adaptive algorithm based uponwindowed average magnitude difference function(AMDF), which is also implemented on DSP.At last, based on the entire spectrum monitoring receiver system, an intergration test has been carried out for the fuction of each module above. Experimental results show that the reciver can support multiple clients and the system data communication mechanism works normally. When the system uses homologous clock, the time delay is0 ns, for FM signal which is received by the antenna, we can get accurate time delay estimation results which the error is less than 100 ns.