The Design Of Impulse Ground-Penetrating Radar Transmitter And Receiver Circuit

Ground-penetrating radar is a kind of new and effective geological exploration method, through the use of high-frequency electromagnetic waves to detect the launch of the purpose of physical and geological phenomena of geophysical exploration methods, also known as ground penetrating radar. With fast exploration speed, non-contact, destructive small, high resolution characteristics, ground-penetrating radar is widely used in geological prospecting , engineering, quality inspection and many other fields. At present, GPR on the market is mostly impulse ground-penetrating radar, so it is greatly worth to study in-depth.This paper firstly describes the basic principle of impulse ground-penetrating radar, according to the requirements of the selective criteria and measuring parameters, the internal structure of impulse ground-penetrating radar system is studied in detail in this paper, focusing on the generating circuit of radar transmit signal and data acquisition circuit. Pluse signal transmitter circuit is a part of the antenna system, which produce a kind of signal with a fixed bandwidth, so we can select appropriate antenna accoding to Bandwidth required. Radar transmit signals are based on the avalanche effect of the transistor which produces a great instantaneous current in order to achieve a narrow pulse signal. The primary circuit can be simulated through the existing simulation software Multisim .We can analyze and discuss the main factors affecting the waveform determine the specific parameters, and design the actual circuit as a transmission signal. Based on narrow pulses which are ns level emitted by the transmited signal of impulse ground-penetrating radar, we can't directly collect data in the receiving circuit.Data acquisition circuit of ground-penetrating radar is designed which is based on the equivalent time sampling method. The circuit by means of integrated high-precision digital programmable delay devices AD9500 generate sampling stepping time, the programmable logic device CPLD and microprocessor are used as the control of the circuit produce the required control signals.The A / D convert analog signals into digital signals and the data acquisition are cached in the dual-port RAM, the data will been collected and transmitted to the PC by use of microcontroller serial communications, saved in the PC and processed later.While data collection method can not achieve real-time data display functions in this paper, but echo signal acquisition of ground-penetrating radar can be basically achieved, and has some advantages of high integration, programming flexibility and scalability.