采用德国acam芯片TDC_GP2实现超声波测量，高精度低功耗芯片TDC-GP2 在热表中的应用 ——新的超声波热表解决方案-Achieved by the German acam chip TDC_GP2 ultrasonic measurement, high precision and low-power chip TDC-GP2 table in the application of heat- a new solution for ultrasonic heat meters