Description:
<jats:p>A simple and feasible modulation scheme called Continuous Pulse Sequence Width Modulation (CPSWM) is proposed to eliminate the crosstalk among multiple ultrasonic sensors in ultrasonic life location system. To improve the performance of multi-life location system (i.e. sharp autocorrelation and flat cross-correlation characteristics), both the continuous pulse sequence (CPS) width and the duration between two CPSs can be modulated using chaotic, pseudorandom or other methods. The duty cycle of each pulse is fixed to be 50%. To adapt to the intrinsic inertia property of ultrasonic transducers, only central work frequency is used in the CPSWM sequence scheme. The CPSWM scheme only uses digital signal generated by a FPGA processor, no D/A converter is used. The experimental results of ultrasonic multi-life location system consisting of two-channel SensComp 600 series electrostatic sensors with the proposed excitation sequences demonstrate that the ultrasonic multi-life location system with the proposed method can realize multi-life location simultaneously.</jats:p>