取樣 sampling

Notes: 

• 取樣(Sampling): 將連續時間(continuous-time)信號轉換成離散時間(discrete-time) 信號的過程
• 取樣率必須比奈奎斯特頻率高出兩倍，因為每個周期最少須取出兩個樣本
• 取樣率需大於信號成分中最大頻率的兩倍：fs >= 2*fmax
• CD 取樣率 44.1 kHz

Ref:

• 取樣定理與混疊效應 Sampling Theorem and Aliasing Effect | Mr. Opengate (mropengate.com)
• Acquiring an Analog Signal: Bandwidth, Nyquist Sampling Theorem, and Aliasing - NI
• jjhuang's Random Notes: 淺談取樣定理 (alberthuang314.blogspot.com)
• Sillycan Valley: Nyquist frequency