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標題: 架構設計與DSP實現電子量測系統之快速高精度新型展頻濾波器
VLSI Architecture and DSP Implementation of Novel Direct-Sequence Spread-Spectrum Filter Architecture for Fast and High Accuracy Electronic Weighing System
作者: 劉佳霖
Liu, Jia-Lin
關鍵字: 電子量測系統;electronic weighing system;傳感器;數位濾波器;直序式展頻;AD7730;DSP;Load cell;RS-232;Digital filter;Direct-Sequence Spread-Spectrum
出版社: 電機工程學系
物體的秤重是日常生活中的一部份,我們經常需要知道許多東西的重量,如食物、產品的組成成分、藥理學(藥的重量),化學藥劑等等。在秤重的領域中,物體被放在以傳感器為基礎的秤重系統上,傳感器是一個不可控制的秤重元件,物體的重量則是由它所產生的電壓訊號經過濾波所測得。各種電子秤在量測過程中,來自傳感器的訊號往往混雜有各種頻率的干擾訊號,如空氣的擾動、汽車引擎的波動、地表的震動、溫度的變化、電子線路的雜訊以及不可控制的因素等等,此等訊號將會影響電子秤的準確度與速度。為了抑制某些干擾訊號,減少干擾訊號在有用信號中的比重,提高訊號的真實性。 因此設計一有效率的數位濾波器甚為重要。
另外,我們也設計一套以DSP為核心的電子量測系統,在軟體方面使用C語言撰寫,經TI DSP Code Composer Studio加以編譯。
最後,我們以UMC0.18 1P6M 的製程完成了電子量測系統之快速
高精度新型展頻濾波器的雛形晶片設計,晶片面積為1021x1021um x um。 模擬結果顯示其的最高操作頻率為100MHz。

The weighing of articles is an essential part of modern life. We usually need to know the exact weight of many items, such as food, ingredients for production, phar-macology, chemistry, technology and so on. In the field of weighing, products are weighed using the load-cell-based weighing system. A load cell is an uncontrollable weighing device and the weight is estimated by filtering the electrical signal from a load cell. Improvement on filtering increases the speed of weighing and enhances the measurement accuracy. In the weighing process, a signal is superimposed by the noise. The noise comes mainly from ambient conditions, such as the air disturbance, the dis-turbance wave from car engine, the seismic wave and so on.
In order to extract the signal we need, it is necessary to develop a digital filter technique which copes with changes of the noise frequency. The filter with the tech-nique can show stable and robust results fast. In this thesis, the two main aims are: (1) to increase the speed of weighing and (2) to achieve good measurement accuracy.
The proposed novel spread spectrum filter algorithm (SS filter algorithm) is to multi-ply the extremely low frequency noise by the key Pseudo-Noise (PN) code. This is to transfer the extremely low frequency noise to the higher frequency noise. Thus, what we need is a FIR filter with “n” tap, and “n” is a small number. With this method, we can increase easily the accuracy of the weighing system. The novel method improves the system to speed up more than 50% and increase the resolution 200% in comparison with the prevision methods.
In the aspect of software, DSP processor (TI TMS320C6711) is used to construct the electronic weighing system. Our software is programmed and compiled by TI DSP Code Composer Studio.
Finally, a prototyping chip of SS filter algorithm is implemented in UMC 0.18 um 1P6M technology. The chip area is 1021x1021um x um . The operation frequency is 100 MHz.
Appears in Collections:電機工程學系所

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