Research On Key Technologies Of HF Frequency Hopping Jammer Based On FPGA

With the rapid development of information technology, the requests of military communication technologies are becoming higher and higher. Frequency hopping communication has been widely used in military communication system because of its outstanding anti-jamming, anti-fading and anti-interception capability.Therefore, the research of frequency hopping jammer is not only a summary and innovation of the previous works, but also the requests of communication development of The Times.This article “Research on Key Technologies of HF frequency hopping jammer based on FPGA” includes hardware and program design.Hardware circuits mainly include baseband circuits and power amplifier circuits.Baseband circuits consist of the FPGA and its peripheral circuits, d/a converter circuits, serial communication circuits and power circuits. The power amplifier circuits include the design of pre-power amplifier and the design of last stage power amplifier.Program design mainly includes data communication between PC and FPGA, design of DDS frequency hopping source, generation of m sequence and signal modulation. The communication content between FPGA and PC can be divided into two categories:modulation sequence and frequency control commands.Modulation sequence can be m sequence which is produced by FPGA, or user defined sequences. User defined sequences are sent to FPGA via a serial port and then processed before modulating with carrier.Control commands refer to the commands from PC which controlling the carrier frequency.By modifying the control commands users can obtain single frequency or multi-frequency carrier. DDS frequency hopping source is mainly based on look-up table.Through periodically querying the designed sine wave amplitude table we can get the discrete sine wave amplitude. In the project, we have designed an m sequence generator whose cycle is127.And the waveform is simulated by Modelsim. 2ASK modulation and 2PSK modulation are realized in this paper. And the modulation waveform figures measured by oscilloscope are presented in the text.In the end, this paper lists the measured output power of the HF frequency hopping jammer. And these measured data meets the design requirements.