Digital Measurement Of Time Based On TDC Technology

In recent years, with the rapid development of high-speed railway, people pay close attention on the way to detect parameters of High-speed train., especially body surface pressure measurement technology. In practice, the traditional measuring technology in the measurement of these parameters, accuracy and lack of immunity gradually shown.This paper set of body surface pressure measurement technology of current status, and proposed digital conversion technology based on TDC time parameter measurement. This paper described the measurement technology of body surface pressure in the first part.And then build a TDC measurement system. The measurement system with low power consumption time interval measurement module as the core of the module to compensate for peripheral circuits and signal conditioning. This can improve the measurement accuracy, lower system power consumption.This thesis is based on the number of TDC time measurement study, in-depth understanding of the development status of the TDC, the realization of a measurement system based on TDC method. Its main tasks are the following:1.Have done a lot of investigation on the body surface pressure measurement technology development. Realization of measurement TDC and TDC measurement module and the main hardware circuits.2. Design the TDC measurement system. Including the sensor signal conditioning module for the time signal; MCU control of TDC measurement module; acquisition and external communication module and power module hardware design. Electromagnetic compatibility and system design and PCB anti-electromagnetic interference problems. Finally, the software design and test system monitoring and parameter adjustment of PC software design.3. Design the surface pressure measurement system base on TDC technology, it is the TDC measurement of specific applications. Based on the characteristics of the body surface pressure sensor, the discharge capacitance measuring system TDC choice Wheatstone bridge design and the calculation of equivalent resistance, and external comparator circuit. Finally, design FAT32 file system on SD card to save the measurement data.4. Deviation analysis of measurement data. Two methods to reduce the deviation, the first use of temperature compensation circuit to adjust. This approach is based on the TDC measurement principle of compensation, using software to achieve. The second is the measurement data to pumping frequency filtering and median filtering.Last, according to the actual progress of the study can be made to improve the system and deficiencies.