摘要:
本文敘述了一個具有高準確度的對數(shù)函數(shù)和通帶較寬的對數(shù)放大器。該放大器用RC充放電的指數(shù)函數(shù)和脈寬調制的方法,提高了對數(shù)函數(shù)的準確度,從而可以解決天文、宇航、精確測量和通信等方面的很多關鍵問題。 根據(jù)RC充放電電壓與時間的指數(shù)關系,再將時間用脈沖調制轉換成電壓,就構成了輸入輸出的對數(shù)關系。使用取樣定理、香農基礎信道容量公式和多級放大帶寬公式等,對該系統(tǒng)進行了理論分析。搭試了一個具體電路,取得了系統(tǒng)特性數(shù)據(jù),證實了該系統(tǒng)的對數(shù)函數(shù)準確度可達99％以上。
Abstract:
A high precision logarithmic amplifier with wide passband is achieved by using the charge and discharge of RC and the method of pulse-width modulation. It can be used in the astronomy, astronavigation, accurate measurement, communication etc. The theoretical analysis of the circuit is given. A practical circuit is constructed, and the experimental result shows that the logarithmic function for the circuit reaches 99% of the theoretical value.
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