摘要
The development of the fog detector was invested by the State Planning Commission and started in July 1997. The prototype's calibration and test was conducted in 1999. Thereafter the detector was improved in the following respects:Hardware: In order to reduce the effects of the background, the transmitter and receiver units were designed to be downwards. A high-power GaAs LED is used for the light sources and for increasing transmitting power. The intensity of the light is monitored and stabilized by a special circuit in the transmitter unit, which receives a part of the emitted light by a
