Design And Research On Multi-channel Real-time Programmable Signal Source With High Precision

The multi-channel real-time programmable signal source with high precision can be used to provide multi-channel and multi-type analogy signals with high precision.In this paper, a new method about signal realization is put forward. Taking advantage of high precision D/A converter and using the DDS principle, we obtained the wave reconstruction circuit; taking advantage of electronic switches, we realized the multi-switching; connecting the computer to the testing platform using a USB bus, we completed the real-time download of wave data, and realized the real-time programmability of the signal source. In this paper, we improved the whole precision of the system by establishing a closed loop controlled system with the high precision A/D converter integrated on singlechip. In this method, the DDS theory, singlechip technology and FPGA technology were combined effectively and made the best use of their merits.Before the hardware design, the factors on output accuracy of amplitude were made detailed analysis and quantity description. On the base of the above analysis, we made the hardware scheme, then estimated the main errors which were ensured as little as much through technology used on the key circuits. The system error was estimated later and it was less than 70 percent of the final system error. In the aspect of software, we modularized the function which to be realize and analyzed the communication between the computer and singlechip and so on then established the communication protocol.Finally, the conclusion and the testing data were given and the method was proved feasible in practice.