Time-domain Ultra-wideband Short Pulse Generation And Echo Sampling System Design And Realization

Ultra Wideband Through-the-wall Detecting Radar (UWB-TWDR) is a new radar system, which can detect the suspicious objects without intrusion and surveil the moving targets inside the building or blindage. It can be widely used for urban-warfare, counter-terrorism and hostage rescue.As a part of the UWB-TWDR experiment system,this article discussses the technology of UWB pulse generator and the echo data collection,includeing the hardware and software design.UWB-TWDR gets the information of objects by emitting UWB pluse.So the the technology of UWB pulse generator is discussed at first. A pulse generator used in through the wall ultra wideband is introduced. Several kinds of commonly used narrow pulse generating methods are presented and their merits and limitations are analysed. Based on the avalanche characteristic of avlanch transistor and RF-BJT, sub-nanosecond UWB pulse is designed and fabricated with satisfying result of 28V amplitude and pulse width of 958ps.Key points and improvements are also discussed.The echos include the information of the detected objects. As the pluse is ultra narrow, the bandwidth of the echo is very wide (over 1GHz) and the echo data cann't be collected by the normal way of singnal sampling. The equivalent sampling technolog is designed to solve the problem. In this paper, the equivalent sampling technology and Phase Lock Loop technology are first introduced. Secondly we designe the ultra-low jitter clock source based on high-precision clock chip AD9510. Thirdly the programmable delay circuit is designed using MC100EP196 to delay the clock source output sequency with a certain step change. Fourthly the collected data is sent to PC using USB2.0 protocol for image displaying. In this part the function block of the CY7C68013A chip which uses USB2.0 protocol is introduced. Finally the CY7C68013A firmware framework and its main functions are introduced. Based on this chip and its GPIF interface, the firmware is programmed. The USB equipment communicate with PC by the equipment driver, so the driver recognition is introduced. The software development plateform is VC++6.0 and the Cypress Library is used to build the PC program code. The result shows that the transfer speed is up to 30Mbps and can achieve the request.