Scanning Thermal Imager To Read Out The Drive And System Power

The scanning cooled thermal imaging system has better MTF, lower noise, betterimaging quality and higher SNR. It has played a vital role in building up our nationaldefense. In the past few years, the Chinese government has increased investment in thescanning focal plane array thermal imaging system. The government also hopes to have abreakthrough in the cooled thermal imaging system and catch up with the westerncountries. In this paper, the drive circuit and the power circuit with lower noise and betterquality are designed based on basic system theory analysis and signal integrity analysis,Good effect is obtained in this paper.Firstly the developmental history of infrared thermal imaging system is looked backbriefly in the paper. And it also discusses the advantage, using places and the generaltrends of the scanning focal plane array thermal imaging system comparing to the starringfocal plane array thermal imaging system.The drive circuit with lower noise and higher precision is designed in the paper. Itincludes the analog circuit, offset voltages circuit and the focal plane array driver circuit.The advanced manipulation circuit, memory circuit and collection circuit are developedrespectively, and these circuits make it possible to implement amplifier, filter and A/Dconversion for the analog signals from the focal plane array, then memorize and transmitdigital image data into a computer. In order to get low noise, high precision offset voltages,the design of the offset voltages circuit is developed by multi-channel, twelve bits voltageoutput Digital-To-Analog Converters. In order to keep the focal plane array detector towork normally, the focal plane array driver circuit is developed by a programmable logicdevice based on the analysis of the main clock and the integral time.In order to get multi-channel, low noise, big current and high requirement fixedcurrent source, the design of the power circuit is developed which can stably supply forfront end analog circuit and back end digital imaging processing circuit.Finally, a summary is given about the design of the drive circuit and the power circuitof the infrared cooled focal plane array thermal imaging system, in addition, theinsufficiency is presented, all of these is the base of the following research on this cooledthermal imaging system.