The Digital Waveform Generator And High-speed Data Acquisition

In the paper, we recount two parts work including researching hybrid waveforms signal generator and studying high_speed data acquisition system. It is based upon the national military affairs beforehand scientific research item named "the waveform research of low probability of interception radar" of the ninth five years plan.On hybrid waveforms signal generator, Nyquist sampling theorem is adopted. In the hardware, we have developed a digital waveform generator applying with high_ speed memory and high speed D/A converter. Which is I Q quadrature channels and is controlled by computer. In the software, we improve and enrich waveform library. This generator can come into being nine kinds of waveforms, which the most frequency is 30MHZ. At the same time, we analyze error characteristic and presented three kinds of hybrid waveforms as a experimentation result. These waveforms include FSK/PSK signal, FSK/PPM signal and PPM/PSK signal. On the base of this generator, to improve system frequency, signal bandwidth and system integration in next research, we introduce CPLD technology to improve on it and make use of MAXPLUS II tool to carry out function simulation and waveform simulation.In channelized digital receiver architecture of radar system, high speed data acquisition the base of dealing with waveforms. We have developed a 50MHZ high speed data acquisition system based on ISA bus applying with both high speed A/D converter and first in first out (FIFO) memory. In this system, the technology of I Q quadrature channels is used, data acquisition synchronously and data transmission asynchronously are implemented. At the same time, we take measure to deal with anti-jamming and analyze ADC dynamic characteristic. Effective number of bits is 7.2, which is tested by FFT test technique. To compare with waveforms of the generator, we experiment on three kinds of hybrid waveforms mentioned in the first paragraph and give acquisition result figure. In addition, on the base of this acquisition system, we simply design a high_speed acquisition system based on PCI bus. It helps to improve transmission speed of acquisition system in next research.This item has been checked and accepted on February 2001 by the group of national radar item.