Research Of Ultrasonic Liquid Flow Test Based On TDC-GP21

As ultrasonic flow meter is a non-contact, wide measurement range, easy installation and maintenance advantages, research of high-precision digital flow meters has great social and economic benefits.According to the differential method ultrasonic flow measurement principle, design a digital ultrasonic fluid flow measurement system. The measurement system is based on enhanced high-precision time-to-digital conversion chip TDC-GP21(Time-to-Digital-Converter, TDC), using complex programmable logic device(CPLD) to assist the digital signal processor(DSP) TMS320F2812 together with the TDC-GP21 constitute the core of the measuring system, to carry out logic control, timing and coordination. The main design of this research are as follows:using the CPLD composed with driving power chip is used to constitute the hardware of the transmitting circuit portion. Good stable power amplifier performance has provided a guarantee for the received signal. The received signal using a digital zoom waveform signal from the gain control(DAGC) the digital AGC constitute MC1350 and peripheral auxiliary circuit system for adapting to different diameter flow measurement. Digital self-gain circuit with two fixed amplification circuit receive no interference signal. And by the comparison circuit so that the received signal is digitized, and the time data measured by the completion of the timer module is based on the TDC-GP21.Software part using time data of the processing timing chip based on DSP to complete data processing and curve fitting of the measurement system, so to achieve a complete data storage, communications, and reset functions, which ensure the system's signal sampling precision and high-speed data processing.