| Pulse signal generator can be used in many fields such as:electronic system testing,ultra-wideband communication,electronic interference equipment,etc.With the increasing complexity of modern electronic systems,the programmability of the pulse signal and the high-resolution adjustment of parameters have put forward new requirements,the traditional analog and digital methods of synthesizing pulse signals have certain limitations,and the adjustment range and resolution of pulse timing parameters are susceptible to sampling rate and The range and resolution of pulse timing parameters are easily limited by sampling rate and memory.In this thesis,we propose an innovative technique for real-time pulse waveform calculation,which can realize a low-cost,memory-free,full-phase,parallel pulse signal generator on the hardware platform of"FPGA+DAC",in which pulse timing parameters and frequency can be adjusted in real time with wide range and high resolution.The main research contents are as follows:1.The study of pulse waveform synthesis real-time calculation technology addresses the problem that it is difficult to improve the pulse waveform timing resolution synthesized by traditional DDS technology,and proposes two pulse waveform real-time calculation algorithms to reconstruct the pulse waveform by accurate calculation of waveform sample points,and to improve the pulse waveform timing resolution by using the idea of sacrificing amplitude for time.In practical engineering,the two algorithms differ in terms of resource consumption and implementation difficulty in FPGAs,and can be applied to scenarios with different hardware conditions.2.The logic of pulse waveform synthesis module is designed and implemented by combining the hardware platform of"FPGA+DAC"to complete the logic program of two pulse waveform real-time calculation algorithms.For the high sampling rate of waveform,we adopt multiple parallel calculations to achieve higher sampling rate;for floating point calculation,we use the host computer to integrate the calculation parameters and send them to FPGA to reduce resource utilization and improve calculation accuracy;for the problem of high frequency pulse amplitude fluctuation,we divide the pulse waveform into fixed number of points per cycle according to frequency and use variable clock to reconstruct the pulse waveform.3.In the background of parallel computing,the trigger function of pulse waveform such as continuous,single and gated trigger requires multiple accurate gating signals to control the interruption of the pulse waveform,which can be cleverly generated by using phase overflow.The advanced functions are burst and PWM,which can use the"storage+real-time computing"architecture to achieve high-precision PWM,and use the characteristics of phase overflow to achieve burst function,and the adjustment range of burst waveform number can reach 2～231-1.The test results show that the designed pulse waveform synthesis module can realize pulse waveform with 2.5 GSa/s sampling rate,maximum frequency 330 MHz,minimum edge time 1 ns,minimum pulse width 1.5 ns,timing resolution 10 ps,and frequency resolution 1 u Hz.The pulse parameters can be adjusted in a wide range of high resolution,and has three trigger modes,PWM and burst advanced functions,which is comparable to the level of foreign Keysight Technology pulse function arbitrary noise generator 81160A. |
