digital aliasing 中文意思是什麼
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Firstly, this paper introduces the basic structure of narrow band fir digital filters. secondly, it analyses the components of narrow band fir digital filters, which conclude cic filter, hbf filter, resampling techniques. based on these analyses, the paper gives the full structure of narrow band fir digital filters and analyses its characteristics, which are frequencies response, anti _ aliasing and anti _ image
本文首先簡單介紹了窄帶fir濾波器的基本結構，然後對窄帶fir濾波器的各組成部分進行了詳細分析，內容包括：積分梳狀濾波器（ cic ）的特性和設計，半帶濾波器（ hbf ）和整形濾波器的特性和設計，重采樣技術的原理與實現。 -
Digital audio aliasing is introduced when one attempts to record frequencies that exceed half the sampling rate
在錄音頻率超過抽樣頻率的一半時，會造成數字音頻混疊失真。 -
From theoretical analysis, we know the existing demodulation methods have limitations as following : one is that the subtraction of the two signals frequencies will display as the result of demodulation when we demodulate two time - domain adding signals without modulating information ( fault information ) ; the other one is that aliasing phenomenon will occur as a result of getting absolute value, detection or square in the process of generalized demodulation analysis, such phenomenon will result in some superfluous frequency composition on the frequency spectrum, which will puzzle the detec tion of mechanical vibration. if the sampling frequency is selected from a suitable range, the aliasing phenomenon will be avoided ; the last one is that aliasing frequencies will be produced in zoom demodulation analysis because this algorithm cannot employ digital low - pass filtering to avert the folding frequencies of higher harmonics in the process of zoom sub - sampling
現有的解調分析方法存在以下三種局限性：將不包括調制信息（故障信息）的兩時域相加信號，也以其頻率之差作為解調信號而解出；廣義檢波濾波解調分析中，由於取絕對值、檢波或平方過程可能產生混頻效應，在解調譜中表現為無法分析的頻率成分，並由此推導出避免這種混頻現象的采樣頻率的選取范圍，從根本上避免此類誤診斷的產生；幾種細化解調分析新演算法中，因為無法在細化分析的選抽時進行數字低通濾波，有可能會出現調制頻率的高次諧波成分發生頻率混疊而反折到低頻部分的現象。 -
As a result, digital images usually suffer from aliasing due to undersampling, loss of high - frequency detail due to relative motion or out - of - focus. supperresolution involves up - conversion of the input sampling lattice as well as reducing or eliminating aliasing and bluring
因此，通常數字圖像因欠采樣（ undersampling ）而引起的信號混疊，因低解析度傳感點擴散（ psf ： pointspreadfunction ）而造成的高頻部分、丟失，以及因相對運動或散焦造成的光學模糊等因素而受損。
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