Study And Application Of The System Of Spread Spectrum Base On ML2724

Spread spectrum communication has many advantages, such as anti-jamming, anti-noise, anti-multipath fading. It can work under low power spectral density at any site, with confidentiality and the capability multi-site reuse. If we measure the distance with spread spectrum technology, we can get a good accuracy .Based on the above advantages of spread spectrum communication in improving the quality of military confrontation and confidential communications played an important role, has been the rapid development and wide application but also broad market prospects.According to spread spectrum theory, the design of the ML2724 Direct Sequence Spread Spectrum (DSSS) communications technology is devoted into the application of communication system with innovation, both voice and text communications capabilities of DS expansion. ML2724 main achieve signal modulation and demodulation, loaded to the pseudo-pseudo-random sequence and function of the control functions of the entire system by the PIC24 MCU. Spreading spectrum, achieving controlling module functions and the compression and error correction of the voice signals are the keys and difficulty to achieve. The main work includes Pseudo-random sequence generation, loading, code acquisition and tracking technology, perfect synchronization to pseudo-implementation, error correction and decoding, and controlling the match rate for each module, the buffer control and so on. In the early time of the issue, I first studied the existing domestic and international spread spectrum technology, drawing on more mature technology in the field. With the study in depth, coupled with my exploration of the ML2724 technology and innovation, the system design was completed and both making PCB board and software programming were carried out.. After continuous debugging and improvement, the system achieved good effect. Finally, I explained the problems which should be pay attention to according to the test result.After tested, the transmission rates reach 1.5Mbps and the spreading gain reaches 35dB. In the laboratory, the bit error ratio of this magnitude in less than ten meters in range, can achieve normal communication in the situation of no barrier. The communication distance reaches tens of meters. As a test board, this design has exploratory significance and reference value for the wider application of ML2724.