Research Of Phase Difference Measurement System Based On DSP

Acquisition and processing of information has become the core of modern information technology, played an important role to social development and technological progress. Phase difference of signal is an important test parameter in the application of modern society. Phase difference which meaning is measuring phase difference between two periodic signals with the same frequency, is basic component of electrical measurement. For example, according to the phase difference of acoustic signal and echo signal, the distance, barrier shape and temperature between two objects can be measured. Therefore, whether the phase difference is measured exactly can decide the accuracy of actual measuring parameters (distances, shape, etc.).In this paper, the development and research status are outlined of phase difference measurement technology in domestic and international. The current measurement methods are introduced. And the characteristics and shortages of various methods are analyzed. Zero-crossing is used in this measurement system. And a kind of phase difference measurement system based on DSP is designed and realized in this paper. DSP2812 is used as the main control chip in this phase difference measurement system. Therefore, the capture unit and A/D module integrated into DSP2812 can be used to measure frequency, phase difference and amplitude of input signal. Channel exchange technology and frequency reduction technology are used to improve the measurement accuracy of the phase difference measurement system. Channel exchange can eliminate additional phase shift from channel. And frequency reduction can convert high frequency signals to low frequency signal before being measured. According to the system need, sine signals with random phase difference are designed and realized to be used as the input signals of phase difference measurement system.Finally in this paper, the function of phase difference measurement system is tested. The major factors affecting the measuring accuracy of system are analyzed in this paper. And the corresponding improving measures are proposed to get better measurement results. Experimental results show that the phase difference measurement system can well measure amplitude, frequency and phase difference of two input signals with the same frequency. The system can also be further extended to realize to phase difference measurement of multi -channel signals.