| As the resolution of optical remote sensing satellites increases,the complexity and technical difficulty of imaging electronics continue to increase,and many new problems arise,such as high-speed detector driving,multi-channel video signal transmission,and crosstalk between channels.High-speed,low-noise signal processing and digital quantization,focal plane thermal control,volume,power consumption,and more.Therefore,it is necessary to solve the above problems by using unconventional techniques to realize a highly integrated modular detector imaging system.In this paper,based on the thick film integration technology and ASIC(Application Specific Integrated Circuit)integration technology,this paper studies the highly integrated modular CCD(Charge-coupled Device)imaging system.Conventional imaging systems are limited by the fixed application types of discrete electronic components,occupying a large space,and complicated heat dissipation processing,and thick film integrated circuits can better solve these problems.Thick-film integrated circuits generally solder the die of the chip directly to the substrate,and can directly fabricate resistors on the substrate.Because the die is a finished circuit,its products have the advantages of reliable performance,easy manufacturing,short cycle and high integration.Therefore,thick film integrated circuits have been widely used in many fields such as aerospace,marine monitoring,and ground observation.Although its integration is higher than discrete devices,it is much lower than ASIC circuits.Limited by the limitations of imaging electronics space and the needs of special circuits,ASIC technology can integrate the circuits of these specific functions to the largest scale,but ASIC technology has the disadvantages of high design difficulty,long cycle,low yield and high cost.The main contents of this paper are as follows:(1)Combined with TDI(Time Delay Integration),the CCD drive load value and frequency requirements are used to analyze the drive signal index,and the specific requirements of the drive circuit index are given.The drive circuit is simulated and verified,and the diode is mainly studied.The driving method of the clamp bias voltage.According to the driving circuit and the TDI CCD power supply voltage parameters,the linear regulated power supply was analyzed.(2)The AFE(Analog Front End)technical index was derived based on the TDI CCD output signal parameters,and the analog front-end circuit was studied.In order to achieve a compromise between sampling speed and conversion accuracy,a mature and reliable pipeline ADC architecture is adopted.The ADC enables high-speed,high-accuracy sampling and conversion.The influence of non-ideal factors on ADC parameters and the design method and steps of pipeline ADC are analyzed in detail.The ADC uses a novel correlated double-sampling circuit structure that increases the gain of the op amp,reduces gain error,and reduces power consumption.(3)Based on thick film technology and ASIC technology,the key technologies of highly integrated modular CCD imaging system are studied.Using the traditional general-purpose chip and PCB steel flexplate,the CCD output image signal is enhanced by the triode emitter follower to increase the output signal strength and transmitted to the dual-channel parallel AFE chip for digitally quantizing the CCD analog output signal,and then transmitted to the field programmable gate array chip.Cache and integration processing,transmitted to the data acquisition card by high-speed LVDS(Low-Voltage Differential Signaling)output chip and imaged on a computer.All of the drive signals and processing timing in the imaging system are generated by a field programmable gate array that allows the computer to control and partially parameterize the imaging system via the RS422 communication bus.Based on the thick film integrated circuit technology,the drive circuit and CCD secondary power supply circuit in the system are studied,which improves the integration degree of the system.The performance of the camera was tested for integration and integration.The experimental results show that the whole system is based on the multi-chip component thick film technology,the drive circuit PCB(Printed Circuit Board)circuit board reduces the area by 2 / 3,and the electromechanical thermal integration design is adopted to realize the camera.High density assembly.The total data output speed of the system reaches 3.6Gbps,and the saturated output image signal-to-noise ratio is 52.6dB.Thick film technology and ASIC technology make the whole system small and modular,easy to integrate electromechanical heat,and provide reference for imaging electronics system of high resolution space remote sensing camera. |
