Signal Integrity Research Based On Aviation And Aerospace Remote Sensing System

The physical connection structure between components can be regarded as transparent in the past low-speed era,not affecting the normal work of the system.As the electronic industry developing towards faster operation speed,more compact system structure,it needs integrate more complex functions in a smaller size of construction.All of these lead the circuit engineers encounter more and more signal integrity problems in the process of system designing.For the development of the aviation remote sensing system,the index of camera is rising.Ground resolution,spectral resolution and frame frequency is becoming higher and faster,which result the amount of the camera's data increase rapidly.The data transfer capacity of the high resolution satellite in GHz is common to see in recent years.All this show that conduct signal integrity research based on aviation and aerospace remote sensing system is urgent needed,but there is rare research reported at domestic or abroad.The signal link of remote sensing system include driver of detector,information acquisition,data processing and data transmission.The driver of detector directly affect the effect of imaging and integral.Because the weak signal and many path number,the signal of information acquisition is easy to distortion.Because of the large amount of data,processing digital data in system orderly is the most time consuming node when debugging the system.Data transmission is generally the highest frequency point in system,and with the most serious signal integrity problem.In this paper,we conduct signal integrity research based on typical hyperspectral cameras.We study the integrity of CCD's drive signal,the power integrity of the information acquisition,the signal integrity key network of the camera's information processing circuit.Finally,we conduct heat dissipation and signal integrity collaborative research on the electric cabinet which is the last data transfer structure of the camera.The main research contents is presented as follow:1)The CCD drive signal have characteristics of high voltage amplitude,big load capacitance.The high frequency of the driving signal will result signal integrity damage under the condition of high frame frequency CCD application,which cause the lower charge transfer efficiency.In this paper,on the one hand,taking advantage of the custom CCD to adopt a series of structure which is benefit to realize high frame frequency CCD.On the other hand,built the complete model of drive circuitbased on the theory of signal integrity,achieve full trap charge capacity greater than300000 electronic in the condition of transfer time is 100 ns,by optimizing the horizontal clock bus structure of CCD and parameters of transmission line.On account of the reduction of line transfer time,indirectly inhibit the trailing phenomenon of CCD.2)The analog signal adjustment module of camera's information acquisition circuit is easily distracted by switch synchronization noise.Using coupled capacitance,plane segmentation,electromagnetic band gap synthetically to enhance power integrity of the short-wave camera's information acquisition circuit.A new type of electromagnetic band gap is designed to meet the bandwidth requirement of the circuit,and the cell of the electromagnetic band gap is compactly to adapt the situation that only using the EBG in part of the board.3)Introducing a new design methodology which is based on signal integrity into the process of the hyperspectral shortwave camera's development.Conduct signal integrity analysis on the camera's signal integrity key network like Ping-pong buffer circuit,high speed parallel-to-serial conversion circuit,backplane transmission circuit.Carry out pre-simulation to get the constraints of layout,conduct the post-simulation to achieve the simulation of the actual signal waveform.Compare the measure results with the simulation results at last.Because of sufficient simulation analysis and flexible using of design rules,greatly reduced the debugging time of the system.4)Hyperspectral imaging has the characteristic of huge amount of data,compressing data in real time inside the system is helpful to reduce the stress on satellite's data transmission module.However,the highest temperature of compression chip work normally is 85 ?.Through simulation,found that under the condition of the environment temperature is 45 ?,the temperature of compression chip reach 86.25 ?,more than the highest limit.Under the balance consideration of the temperature control of the chip and the integrity of the data compression signal,add another heat conduction path to reduce the temperature of the chip.The simulation results and the thermal vacuum test show the method meet the requirements of the indicators,the highest temperature of chip drop to 74.25 ?.