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Circuit Design for a DSP Based Laser Signal Detection System
Date Issued
2007
Date
2007
Author(s)
Cheng, Yu-Ming
DOI
zh-TW
Abstract
In this thesis we develop the digital signal processing subsystem for a reflecting laser range finder. The laser range finder shines a frequency modulated laser beam at the target surface. The distance traveled by the laser beam creates a short time delay in the nanosecond range. One can calculate the distance to the target if he has the mean to measure this very short time difference. To target this difficulty, the precision system control laboratory developed a double frequency shifting (DFS) technology to transform the time delay measurement into a phase difference measurement and to shift the carrier frequency down to a slower 10 KHz range for easy measurement. This thesis builds the hardware circuit and the DSP based phase difference sensing device for the measurement. We convert the frequency modulated signal into digital on-off signal and use the capture feature of the DSP to capture the bit change event and to count the resultant time delay for phase measurement. Experimental results confirm 0.4 to 2 cm measurement resolution from the device hardware.
Subjects
雷射測距
相位法
訊號偵測
數位訊號處理器
laser range finder
double frequency shifting (DFS)
signal detection
DSP
Type
thesis
File(s)
No Thumbnail Available
Name
ntu-96-R94522815-1.pdf
Size
23.53 KB
Format
Adobe PDF
Checksum
(MD5):26b21b5b27c1a3ed52a6f89579cff836