During the last few decades, photothermal radiometry（PTR） has been greatly developed and widely applied in the field of nondestructive testing. However, the traditional PTR system employs an expensive lock-in amplif...During the last few decades, photothermal radiometry（PTR） has been greatly developed and widely applied in the field of nondestructive testing. However, the traditional PTR system employs an expensive lock-in amplifier to detect the weak photothermal signal, which leads to high cost and long test time. In this paper, a fast transmission PTR system based on sampling by using an internal computer sound card was developed to lower the system cost and shorter the test time. A piece of amorphous silicon（a：Si） thin film solar cells with artificial defects was prepared and tested by the system. The results show that the sharpened defects can be identified easily and quickly according to the significant peaks of the original infrared signal sampled by the internal computer sound card. Furthermore, more detailed defects can be investigated by processing the infrared signal. These validate the effectiveness of the proposed transmission PTR system as a low cost and efficient non-destructive test technique.展开更多
This paper deals with the issue of using the MATLAB tool in teaching the course of communication principles via constructing an Amplitude Shift Keying (ASK) communication system. Different from conventional MATLAB bas...This paper deals with the issue of using the MATLAB tool in teaching the course of communication principles via constructing an Amplitude Shift Keying (ASK) communication system. Different from conventional MATLAB based simulations, the constructed system transmits modulated signals through a wire audio channel by exploiting sound card. Synchronization is required before the received signal being demodulated. Many practical problems should be considered as in real system. The designed system can be extended easily, and not only stimulates students’ interest in communication course, but also helps them understanding the principles from system viewpoints.展开更多
基金supported by the National Natural Science Foundation of China under Grant No.61379013the Excellent Doctoral Academic Support Program under Grant No.YBXSZC2013021
文摘During the last few decades, photothermal radiometry（PTR） has been greatly developed and widely applied in the field of nondestructive testing. However, the traditional PTR system employs an expensive lock-in amplifier to detect the weak photothermal signal, which leads to high cost and long test time. In this paper, a fast transmission PTR system based on sampling by using an internal computer sound card was developed to lower the system cost and shorter the test time. A piece of amorphous silicon（a：Si） thin film solar cells with artificial defects was prepared and tested by the system. The results show that the sharpened defects can be identified easily and quickly according to the significant peaks of the original infrared signal sampled by the internal computer sound card. Furthermore, more detailed defects can be investigated by processing the infrared signal. These validate the effectiveness of the proposed transmission PTR system as a low cost and efficient non-destructive test technique.
文摘This paper deals with the issue of using the MATLAB tool in teaching the course of communication principles via constructing an Amplitude Shift Keying (ASK) communication system. Different from conventional MATLAB based simulations, the constructed system transmits modulated signals through a wire audio channel by exploiting sound card. Synchronization is required before the received signal being demodulated. Many practical problems should be considered as in real system. The designed system can be extended easily, and not only stimulates students’ interest in communication course, but also helps them understanding the principles from system viewpoints.
