Design of Multi-channel Pulse Signal Generator with Adjustable Time Sequence*

The development of electromagnetic launch technology imposes higher requirements on the discharge control of Pulse Forming Networks (PFN). This paper introduces a multi-channel time sequence pulse signal generating platform based on FPGA NiosII system. The user logic is designed by employing modular programming methodologies. Furthermore, the host computer software is developed utilizing the Qt Creator to facilitate comprehensive control over 30-channel output pulse signals. Within a short delay range, the adjustment step size of channel output time sequence can reach 20ns. To meet various discharge requirements, the signal generator is designed with the capability to store multiple sets of time sequence data. Upon receiving of a designated group number, it promptly calls the corresponding time sequence to generate trigger pulses, thereby swiftly modulating the output current waveform of the PFN. To verify the correctness of the FPGA logic program, SignalTap II Logic Analyzer, an embedded logic analyzer of the Quartus platform, is used to logically judge the FPGA output signals. Additionally, a digital oscilloscope is employed for precise measurement of analog signals from FPGA pins. The experimental waveforms demonstrate that the FPGA logic program meets the design requirements. The connection between host computer and FPGA is established through serial communication for joint debugging and testing. In order to test the signal generator's adjustment functionality of time sequence, the host computer issues the group number. Test results substantiate that output pulse signals of the signal generator are accordant with the setting of the host computer, and the generator can update the output time sequence online based on the received group number. Applying this signal generator to PFN systems allows flexible adjustment of multi-module trigger time sequence according to discharge waveform requirements, which is beneficial for improving the discharge accuracy of PFN systems and expanding their application environment.