In low-frequency elastic wave through-the-earth communication system,because of multipath transmission caused by characteristics of the layered earth,the time domain equalizer is different from other wireless communication systems.A modified LMS algorithm of variable step size is proposed based on improvement of traditional LMS.On the base of principle and simulation analysis,the improved Least Mean Square(LMS)algorithm is analyzed and the performances are compared between the improved LMS algorithm and traditional LMS algorithm.In the improved algorithm,the contradiction between convergence speed and the steady-state error is considered at the same time.Therefore,the improved algorithm has good convergence properties and channel-tracking performance.
For the issue of nuclear radiation detection,this paper designs a remote control nuclear radiation detector which can trace a pre-determined route,avoid obstacles effectively,and can be controlled remotely by users wirelessly or through voice command.It can effectively replace manual probing due to convenience,flexibility and safety.The system mainly consists of a nuclear detection module,a voice control module,a route tracing module,an obstacle avoidance module,a data transmission module,storage and a display module,and a D.C.machine.An MSP430 microcontroller is used as a control chip to control the motor and the system uses infrared technology and ultrasonic sensors to achieve intelligent tracing and obstacle avoidance.Moreover,it applies a voice module and data transmission module to remotely controlling the device.The radiation data is shown on an LCD screen.
