System Design Of Low Noise CCD Measurement Base On The ARM

ARM-based low-noise CCD measuring system is a non-contact measurement system. On the basis of previous studies, this paper makes an in-depth analysis of the noise source of measurement system, identifies the reasons of impacting precision and accuracy of measurement system, and purposes a low-noise measurement system design project. In the technical route, this paper uses the basic ideas and methods of weak signal data acquisition. Based on the hardware platform of FPGA + ARM architecture, a low-noise CCD measurement system is designed and realized combining with theoretical analysis and experiments. The main work are followed:1. The design of the hardware platform. This paper uses a platform of FPGA+ ARM architecture. According to the system requirements, puts forward the detailed design of hardware platform, including chip selection, module design, interface design, as well as the production of PCB. Detailed design considers the circuit board's test and low-noise.2. In the CCD measuring system, collaborative design of control system timing-driven is one of the key technologies. In the view of the design requirements, the CCD chooses TOSHIBA Corporation's TCD1209D; correlated double sampling devices chooses ADI's AD9945; buffer chooses IDT's IDT7204; therefore drive control time mainly includes CCD driver pulse, correlated double sampling clock, IDT7204 control pulse of the reading and writing. In this paper, detailed analysis of the design process, the simulation waveform and measured waveform are introduced, the experiment and simulation are in good agreement.3. According to CCD structure and working principle, the emergence reasons of attached to the output signal noise are analyzed carefully to identify the main noise. A wide range of noise restraining measures are adopted, including low-pass filter to restrain white noise, correlated double sampling technique to restrain reset noise; the low-noise design of PCB. And the designs of the linear power of low noise/ripple can reduce noise effectively. The paper purposes the measured results of the ripple noise, about 10mv, meeting the system design requirements.4. Main control program is the soul of measurement system, the various parts of the hardware circuit in the main control program work together to complete CCD signal acquisition, conversion, processing and transmission. Measurement control program is developed in the Keil environment, in the meantime, the functional modules and processes are introduced.