The Development Of Detecting System Based On Sh-SAW Sensor Array Technique

In recent years, SAW-based array sensors apply widely to the realms of environmental and biochemical monitoring. Contriving a miniaturizing general-purpose real-time processing system, based on SAW micro-sensor array technique, has good prospect of practical application.In this paper, we design a kernel system of real-time and field-test analytical apparatus to detect the various poisonous pollutants in environmental waters. First, we analyze the output frequency signals of six SAW array sensors. According to the designing request of this system, the measuring accuracy of each channel should be within 0.1%. To reach the accuracy, we solve the problem of multi-channel real-time parallel counting at the same time by designing a fast processing circuit composed of DSP, CPLD and a special frequency counter IC. Then, we design a selective high frequency divide module to broaden the detecting frequency band to 1.1 GHz. Finally, we design UART communication and USB2.0 communication to connect DSP to PC. Therefore, an application program of well man-machine conversation in PC can operate pump and valves in the liquid specimen system of detecting apparatus to run according the testing project. In addition, we use NIGraph Active control of NI Measurement Studio to display the data acquisition of the multi-channel.The system can reach the design requirements in actual operation, and lay groundwork for the development of environmental waters real-time and field-test analytical apparatus.