The Design Of Frequency Synthesizer Applied In FMCW Automotive Collision Avoidance Radar

In recent years, the radar equipment is gradually being used in variousnavigation and targeting system. Especially in the constant pursuit of faster speed andhigher safety factor contradictions, it becomes imminent how to balance thisrelationship. Thus, in this case, the automotive collision avoidance radar is proposed.Instead of the ultrasonic and infrared collision avoidance system, FMCW radar hasbecome the best choice for short-range targeting radar for its precision targetingcapability, the simple transmit waveform, low emission power and sophisticated digitalsignal processing algorithms.The research of radar system is always inseparable from the development offrequency synthesizer working as an import part of radar system, and emitting a powersignal with specific waveform feature easy to digital signal process.Based on the project “Ka-band FMCW automotive collision avoidance radarsystem (with34.25GHz-34.75GHz coverage)”, this paper choosed the method “DDSdirect-driving PLL” to implement a4channel frequency synthesizer with5ms period,25MHz bandwidth and8.5675GHz-8.6825GHz coverage, and it can be directly appliedto FMCW radar system or scanning equipment. It is easy to switch between channelusing software, and the switching time is less than250us. The main tasks are as follows:1. It is discussed that the automotive collision avoidance radar’s research status inthe world and the basic measurement principle.2. It is compared that the difference among the kinds of FMCW frequencysynthersizers based on DDS and PLL technology.3. According to the system requirements and the planning of spectrum, this paperwill introduce the register factor’s calculation processing and give the design process ofthe main circuit.4. The problems and solutions of the process of hardware debugging are analisized.