數(shù)字濾波器簡介外文翻譯-免費閱讀
【正文】 s memory. This means the digital filter can easily be changed without affecting the circuitry (hardware). An analog filter can only be changed by redesigning the filter circuit. 2. Digital filters are easily designed, tested and implemented on a generalpurpose puter or workstation. 3. The characteristics of analog filter circuits (particularly those containing active ponents) are subject to drift and are dependent on temperature. Digital filters do not suffer from these problems, and so are extremely stable with respect both to time and temperature. 4. Unlike their analog counterparts, digital filters can handle low frequency signals accurately. As the speed of DSP technology continues to increase, digital filters are being applied to high frequency signals in the RF (radio frequency) domain, which in the past was the exclusive preserve of analog technology. 5. Digital filters are very much more versatile in their ability to process signals in a variety of ways。 該 濾波器對信號的 影響 就 是類似 于模擬 電路中 的微分電路 。 在下一節(jié)，我們將看看一些簡單數(shù)字濾波器的例子。這 對于理解 如何設(shè)計 和 使用數(shù)字濾波器 是 一個必不可少的。這些計算通常都涉及乘以由常量與輸入信號相加的最終輸入值。 模擬濾波器是由模擬電子電路組成的，如電阻、電感和運算放大器來產(chǎn)生所需的過濾效果。這樣的濾波器電路被廣泛應(yīng)用在噪聲的降低、視頻信號的增強、音響系統(tǒng)中的圖像均衡以及其他的多個領(lǐng)域中。 如果需要，這些現(xiàn)在代表采樣的信號值濾波結(jié)果 的 計算，是 由 一個 DAC（數(shù)字到模擬轉(zhuǎn)換器）輸出的信號轉(zhuǎn)換回模擬形式。 假設(shè)被數(shù)字化的“原始”信號以電壓波形的時間函數(shù)來描述： V ??x(t) 其中 t代表時間。 簡單數(shù)字濾波器 下面例子說明了數(shù)字濾波器的基本特征 ： 1. 單位增益濾波器： 每一個輸出值 yn 與輸入值 xn 相等 ： y0? x0?y1 ?x1?y2 ?x2?...etc 這是一個 經(jīng)常用到的濾波器 ， 濾波器對輸入信號沒有影響 。 5. 均值濾波器 ： 該 輸出值是當(dāng)前輸入值和前一個輸入值的平均值（算術(shù)平均）。 this includes the ability of some types of digital filter to adapt to changes in the characteristics of the signal. 6. Fast DSP processors can handle plex binations of filters in parallel or cascade (series), making the hardware requirements relatively simple and pact in parison with the equivalent analog circuitry. Operation of digital filters In this section, we will develop the basic theory of the operation of digital filters. This is essential to an understanding of how digital filters are d
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