Commercial off the shelf direct digital synthesizers for digital array radar

Abstract

Up until the 1980s, conventional radar systems consisted primarily of analog circuits, which are costly to build and compatible only to a narrow band of operations. Modern digital technology offers increasing capabilities at a lower cost making it attractive for modern radar application. The Direct Digital Synthesizer (DDS) is one such example of digital technology that is now routinely found in newer radar system designs. The DDS characteristics that most attract radar-system designers are precision frequency tuning, phase offset control, and linear "chirp" capability. This study discusses the option of incorporating DDS for use in a digital pulsed and/or frequency modulated continuous wave (FMCW) radar, and examined the necessary adaptations such as up-converting baseband signals from DDS to a radar transmission frequency, viable transmit and receive waveforms and the synchronization problem relating to synchronizing the many radiating elements that could range from a few to possibly thousands.