A Research Of Software Defined Multi-channel Coherent Signal Synthesis Architecture

As the core component of electronic and communication equipment,the coherent performance of signal source directly affects the accuracy of satellite positioning,the accuracy of radar speed measurement and ranging,and the anti-jamming performance.With the vigorous development of the new generation of wireless mobile communication industry,the application scenarios of signal source are gradually expanding,and the flexibility of multi-channel coherent signal source structure design needs to be improved.Software defined architecture(SDA)is a user-oriented and layered architecture.Users can interact with the underlying hardware resources through the upper application software of the architecture,which is very convenient and flexible.A scheme that combines SDA with signal source structure design and coherent performance simulation is designed to improve its flexibility and coherence.Based on the theory of signal synthesis,the core components of the signal source are modeled on the relevant simulation platform.The simulation tests of PLL,DDS,divider,mixer and multiplier are carried out.The results show that the models can operate normally.By calculating and analyzing the phase noise of the output signals of the models,the results are consistent with the derivation of the theory of signal synthesis,which shows that the models can simulate the actual phase noise characteristics of the signal source component.A multi-channel coherent signal synthesis framework is built by using the above signal source component model,including typical DDS-driven-PLL architecture,DDS+ PLL in loop mixing architecture and DDS + integer-PLL out of loop mixing architecture.Aiming at the problems of poor frequency locking state and high phase noise of DDS + integer-PLL out of loop mixing architecture,DDS + fractional-PLL out of loop mixing architecture and PLL-driven-DDS out of loop mixing architecture are designed,the test results show that the multi-channel signal synthesizer based on this framework has low phase noise.Based on the multi-channel coherent signal synthesis framework,the software defined multi-channel signal synthesis framework is designed by combining with the idea of software defined architecture The architecture is divided into three layers.The upper application layer is responsible for the direct interaction with users,the middle virtual layer is responsible for providing the call logic to the bottom module,and the bottom infrastructure layer contains all the simulation models for the upper layer to call.The simple interaction between the user and the basic structure of multi-channel coherent signal synthesis improves the flexibility and reconfigurability of the whole system.A multi-channel coherent signal synthesis optimization design system based on software defined multi-channel coherent signal synthesis architecture is developed.The system realizes single channel manual parameter input mode,automatic parameter calculation mode,multi-channel parameter calculation and coherent performance optimization function.The test results show that the software has practical operability and robustness,and the function is relatively perfect,which can provide advices for multi-channel coherent signal synthesis The design of channel coherent signal synthesizer provides pre-simulation function to optimize the coherent performance of multi-channel signal source.