No abstract

No abstract

This paper analyzes the variation of A-phase and Bphase pulse signals that displacement sensor outputs. A new anti-jamming counting approach is designed according to Gray code. This counting approach does not cause error count and counting precision is improved by four times frequency count. The principle of hardware and software is indroduced in two application examples. In the first example, the input ports of AT89C52 MCU are connected to the outputs of hand rotary encoder. The MCU constantly checks the state of inputs in the timer interrupt and counts with this counting approach, then the count value is transfered to host computer through the RS422 interface. In the other example, the outputs of optical encoder are connected to the I/O ports of CPLD/FPGA chip which can count with this counting approach. Then the count value is transfered to host MCU/DSP through data lines. The applications resulted that the approach is good and the hardware circuit is simple, stable and reliable. The method has a certain practical value and can be applied to the antijamming counting for the other sensors which have the same output waveform.

A movable instantaneous impact pressure test device is designed and achieved, according to the characteristic of instantaneous impact wave such as acutely variation and large range of pressure, adverse conditions on the spot. A piezoresistive transducer of high-frequency an high pressure is selected and used. MEMS technology is adopted to design and manufacture the sensor that is flush packaged. In addition multi-channel analogue amplified circuit and DSP control core circuit are studied. So the multilevel multiple pressure analogue signals can be achieved. The circuit can take charge of high speed sampling, processing and storing of analogue signal too. Software modifying mode, process parameter and data transmission is also developed. The device has the function of scheduling of timing sample, automatic gain of magnification, automatic detection of the beginning of impact pressure, parameterization of working mode and process etc. It is a practical instrument with battery as power supply, the low power consumption of power supply control mode and the solid mental shell for testing explosion shock wave. Pressure test results indicated accurate pressure waves of instantaneous impact can be got with the instrument.