| This paper designs a two-way video signals transmission of wireless laser transmission experimental teaching system, as a prototype for experimental teaching. In transmitter, we analyses the process of the second modulation of image signal, designs analog signal amplitude modulation circuit; uses semiconductor laser as light source, wavelength of 650nm, optical output power of 5mW, internal modulation. Using a simple convex lens as the optical antenna. In receiver, using Si-PIN detector for receiving, using heterodyne detection receive; designs receiver, high-frequency amplification, local oscillation and mixer circuit; IF amplification and video detection circuit use TA7680AP to achieve. Using frequency division multiplexing to achieve two-way signals transmission, designs a two-way signal transmission circuits. A simulation of the image signal modulation and receive is achieved in the laboratory and different parts of the system's characters of waste and confidentiality are given qualitative analysis. An overall system debugging result is achieved, the schemes for improving are proposed. |
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