When multiplexed detectors are used, multiplexing techniques are often used to convert multiple signal channels into a single signal channel. There are two ways to realize the multiplexing technology, that is, sampling and holding and parallel/serial out of CCD.

 

The sampling and holding method is to send the output signal of the preamplifier to an electronic switch, and the electronic switch samples each unit in sequence and repeats this process periodically, and then outputs the input signals of multiple channels to a single channel in time sequence. It is difficult to achieve high speed and low noise for such electronic switches. The working principle of the parallel/serial-out mode of CCD. The parallel scanning device of the infrared detection CCD device samples the scene or image at the same time, and at the same time converts the radiation signal of the corresponding unit into an electrical signal. The charge in the clock pulse is shifted out, and the output circuit forms a group of video signals corresponding to the sampling signal, thus completing the conversion from multiplexing to single-channel transmission.