DDS Signal Generator Of PXI Bus Interface Based On FPGA

In the test system, the signal generator has been an indispensable tool that providesan excitation source for the test system. With the advance in technology and process,test equipment is developing toward miniaturization, intelligent and networking, andtesting capabilities continue to increase, while the frequency of testing is also rising,which puts forward higher requirement on the signal source of test system to be able tooutput not only various complex waveform, but also higher frequency, meanwhile theinstrument interoperability must be high, so that the cost of maintenance and testingprocess can be simplified. In general, there is the need which is that the sourcemodulation ability is more and more strong, the source can achieve maximumfunctionality at minimum volume, taking into account reliability, compatibility andmaintainability, which is a very important development of test equipment in the future.DDS based on FPGA can produce high-performance, high-precision signal source,so its superiority is increasingly obvious, and the PXI bus interface, as a universalinterface, has the advantages of miniaturization and speediness, can provide technicalsupport to the miniaturization development of signal source.This article gives out the overall structure, and then describes the DDS basicstructure, working principle and the achieving results in detail, also makes a furtherdetailed description of the PCI bus structure,the signal definitions and theimplementation of PCI interface logic based on the PCI soft core, and finally gives outthe principle diagram and the real figure.In addition, DDS principle is applied tocomplete DDS signal generator to achieve the basic waveform, such as sine wave,square wave and triangle wave, while based on the PCI IP core, which comes fromFPGA manufacturer, ALTERA, PXI interface logic that has the ordinary CPU functionto read and write is implemented, the results have be analyzed, making the signalgenerator has obvious advantages in test equipment.