Research On Special Test Waveform Generation Technology Base On FPGA

In order to meet the testing requirements of high-precision time-related eventacquisition system, a testing signal source was needed to simulate the event signal. Thistesting signal source is required to generate a series of modulating pulse, and theposition and number of the pulse can be designed by artificial modulation. This pulsenot only could be a separate pulse,but also might be a sequence of pulses, differenttesting wave represents different time information, thus providing a time-related event,wherein the modulated pulse could continuously changed the duty cycle and thecorresponding number, the number of the type of the different duty cycle of the pulsemight be the same, in accordance with the requirement of the testing system it couldalso be designed as linear number or nonlinear number, the duty cycle could also belinear variation, so the data collection terminal could depend on the excitation signalprovided by the testing source, to verify the time accuracy of the data acquisition system.In addition, in order to expand the function of the system, the testing system alsoincludeed a conventional waveform generator, including the function with waveformpeak acquisition and frequency acquisition, could be used as the normal signal generator,at the same time might be prouduced some common digtial modulated wave.This paper firstly discussed the technical solution of the testing signal source, theconventional waveforms adopted the MAX038chip with waveform conditioning circuit,special testing waveform and modulated wave used EP2C8Q208C8N of the FPGA chipas the master chip, by used two pieces of DA to modulate DC level and digitalmodulation based on DDS principle, on the basis of this it coule expediently export thespecial testing square wave and digital modulated wave; the next paper elaborated threeaspects of content, respectively were the key technology of the system, hardware andsoftware. In the logic part of FPGA, the paper used mixed input mode with Veriloglanguage and schematic, and the top-level document adopted schematic description, soit could be easily understood, with that the system used double display modes of LCDand digital tube to show the peak and the frequency of the waveform, or the type of thewaveform, combined buttons to select the desired waveform. The waveforms of thesystem included sine, square, triangle, sawtooth as four basic waveforms, three digitalmodulated waveforms as ASK, PSK, FSK and a variety of special testing pulsewave.Finaly, the system completed joint debugging with the hardware and the software part, and the results showed that the special testing signal source of this thesis had theadvantages of flexible function, strong waveform scalability, hign stability waveformand the low cost design.