SDR Technology Research And Implementation For Certain Type Of HF Communication Equipment

With the emergence of software radio technology and digital signal processing chip, the rapid development of digital radio development of our military equipment has become a necessity. Digital receiver / exciter of short-wave is part of the equipment by the digital IF section extends to the RF part.Digital Receiver/ exciter of short-wave works are divided into two areas to receive and exciter:Receiver: the receiver using a high-frequency program, will receive the 2~30MHz radio frequency signals into intermediate frequency signals;IF digital processing technology using the IF modulation, framing, transmission,frame solutions, demodulated into an audio signal.Exciter: A zero-IF scheme, sampling 3KHz the audio signal, after sampling,modulation, framing, transmission, frame solutions, demodulation, modulation into 2 ~30MHz RF signal.Firstly,dissertation briefly describes the background paper topics, and then focused on the digital receiver and exciter of the need, purpose and meaning.Secondly, given the overall shortwave receiver actuator design, and digital receiver according to the basic theory of exciter designed to build the hardware platform,software design is given to explain the critical devices; study the zero-IF design technology and technical difficulties, given the implementation of the results;introduced platform SSB, AM, CW, signal level estimation, AGC control, decision feedback equalizer design methods and receive/excite in the console.Finally,through shortwave receiver and exciter actuator research, the development of short-wave digital receiver and exciter digital level, changing the past digital equipment must be IF and analog move to the RF of the traditional model, realized directly from the baseband signals are digitized to a radio. Developed digital receiver and exciter, fully functional; performance indicators in line with technical specification requirements.The design advantages are: the device uses a high frequency transmit and receive zero-IF solution, simplifying the circuit, reducing the combined frequency and improve the indicators; digital IF LVDS bus transmission technology used to improve the digitallevel; digital IF quadrature modulation and demodulation techniques, improved anti-jamming capability; by differential bus of the receiver and exciter control, changed the traditional way of discrete wire control, improved anti-jamming performance;The capabilities of the device is fully under software control, debugging easy, not only to enhance the flexibility of the equipment, but also shorten the upgrade cycle,reducing upgrade costs.Developed in this paper digital shortwave receiver / exciter better performance, and has been used in practice.