Design Of Signal Processing Circuit For Miniaturized Terahertz Camera

In the entire electromagnetic spectrum,electromagnetic waves with a frequency in the range of 0.1THz to 10THz(wavelength 0.03mm to 3mm,1THz=10¹²Hz)are called terahertz?THz?.It is in the microwave and infrared range.Because of its special characteristics,terahertz waves have broadband,low energy,water-repellent,and penetrating properties,and so on.Based on these characteristics,terahertz imaging detection technology combines the advantages of both micro/millimeter wave and X-ray,so terahertz imaging technology has broad application prospects in homeland security,non-destructive testing,biomedicine and other aspects.With the advancement of basic science and the development of uncooled terahertz focal plane manufacturing technology,terahertz imaging systems are developing in the direction of miniaturization,high integration,low power consumption,and low cost;based on this,design high integration,small The terahertz camera signal processing circuit system is of great significance.In this paper,based on the electrical characteristics of uncooled terahertz detector,a miniaturized terahertz camera signal processing design based on ASIC?Application Specific Integrated Circuit?is selected.The paper uses a 320×240 uncooled terahertz focal plane detector and uses ASIC chip JL7603B of Chengdu Jinglin Technology Co.,Ltd.as the system core processor.The system includes a drive circuit for a terahertz detector,an ASIC signal processing circuit,and an imaging output display circuit.The terahertz detector is driven by a high-quality voltage source,an adjustable DC bias voltage,and a digital logic sequence that guarantees the normal operation of the detector.It converts the information of the target object into an analog output signal,which is convenient for image data acquisition and image processing.A 14-bit ADC?analog/digital converter?LTC2245 chip is used to digitize the detector's analog output signal.The 14-bit digital signal output by the ADC is subjected to imaging preprocessing by the ASIC chip JL7603B,and the internal SDRAM of the JL7603B is buffered for subsequent calls.The ASIC converts the processed 14-bit digital signal into an analog signal from Chrontel's video encoder CH7026 for video output display.At the same time,a USB2.0 microcontroller CY7C68013A chip is used.In Slave-FIFO mode,the data transmission and collection of 14-bit digital signals processed by ASIC are realized through USB2.0.The thesis details the communication protocol between ASIC and PC,and configures and debugs the corresponding parameters of the miniaturized terahertz camera through PC-side debugging software.Finally,the paper debugs and verifies the designed and implemented miniaturized terahertz camera signal processing system.The three-dimensional size of the entire camera core is 25mm×25mm×35mm,the weight is less than 70g,and the power consumption is as low as 1.2W.It has achieved design goals of miniaturization and low power consumption.At the same time,real-time imaging of 2.52THz radiation can be realized.The RMS noise of the system can be calculated to be 588.6?V by collecting image data,and the noise non-uniformity is 9.91%.Through the above tests,the system meets the design requirements,and provides a possible technical solution for a more integrated and more compact handheld terahertz camera in the future.