Data acquisition processing system applies to atomic force microscope

Abstract

The invention discloses a data acquisition and processing system applied to an atomic force microscope, which comprises a PC-104 bus, an FPGA processor, a data acquisition unit, an analog output unitand a sine wave generating unit. The system utilizes the FPGA to control the acquisition and adopts the digital filtering technique and the desampling technique to make the single channel acquisitionrate reach 3,000,000 times per second and the multi-channel acquisition rate exceed 1,000,000 times per second, so as to meet the requirements of high speed scanning; the FPGA is utilized to control the analog output and realize the four-channel independent analog output, and the speed of analog output exceeds 1,000,000 times per second; and the phase difference in a vibration period of a probe can be detected by utilizing the FPGA to control the phase detection and adopting the digital phase demodulation technique, each phase testing time is shorter than 5-microsecond, the phase detection precision exceeds 0.5 degree, and the linearity range can reach 0 to 360 degrees.

Description

technical field [0001] The present invention relates to a data acquisition and processing system, more particularly, to a data acquisition and processing system applied to an atomic force microscope. Background technique [0002] With the rapid development of nanotechnology, ultra-high resolution microanalytical instruments such as scanning tunneling microscope (STM) and atomic force microscope (AFM) have become indispensable and important tools for nanotechnology workers. The atomic force microscope uses a very thin probe on a flexible cantilever beam to approach the measured surface. When the measured surface is scanned laterally, the fluctuation of the surface changes the distance between the surface and the probe, thereby changing the interaction between the two. Force - atomic force, by moving the needle tip or sample longitudinally, maintaining a constant atomic force to measure the surface profile, the resolution can reach the nanometer level. The atomic force micros...

AI Technical Summary

Problems solved by technology

[0004] The data acquisition and analog output parts of the existing atomic force microscope include three types: the first type uses analog electronic technology, and uses analog devices to complete signal calculation and PID control. The disadvantages are large volume, high energy consumption, fixed parameters or only It can be adjusted in a small range, and it will not work properly when no one is operating it

The second type adopts the mode of personal computer (PC) plus data acquisition card, and its disadvantage is that the personal computer is bulky, high power consumption, low data acquisition speed (less than 100K / time) and slow scanning and imaging speed

The third category uses a dedicated digital signal processor to achieve full digital control. The disadvantage is that all modules (components) of the system are customized, the cost is very high, and technology upgrades are difficult.

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