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好歌一首 傅立葉之歌orz 大家一起來唱~~ http://eceserv0.ece.wisc.edu/~sethares/mp3s/fourier.html 以下是歌詞: Integrate your function times a complex exponential It's really not so hard you can do it with your pencil And when you're done with this calculation You've got a brand new function - the Fourier Transformation What a prism does to sunlight, what the ear does to sound Fourier does to signals, it's the coolest trick around Now filtering is easy, you don't need to convolve All you do is multiply in order to solve. From time into frequency - from frequency to time Every operation in the time domain Has a Fourier analog - that's what I claim Think of a delay, a simple shift in time It becomes a phase rotation - now that's truly sublime! And to differentiate, here's a simple trick Just multiply by J omega, ain't that slick? Integration is the inverse, what you gonna do? Divide instead of multiply - you can do it too. From time into frequency - from frequency to time Let's do some examples... consider a sine It becomes a phase rotation - now that's truly sublime! And to differentiate, here's a simple trick Just multiply by J omega, ain't that slick? Integration is the inverse, what you gonna do? Divide instead of multiply - you can do it too. From time into frequency - from frequency to time Let's do some examples... consider a sine It's mapped to a delta, in frequency - not time Now take that same delta as a function of time Mapped into frequency - of course - it's a sine! Sine x on x is handy, let's call it a sinc. Its Fourier Transform is simpler than you think. You get a pulse that's shaped just like a top hat... Squeeze the pulse thin, and the sinc grows fat. Or make the pulse wide, and the sinc grows dense, The uncertainty principle is just common sense. ----- 祝期末考順利XD!! -- ※ 發信站: 批踢踢實業坊(ptt.cc) ◆ From: 61.228.72.203 ※ 編輯: hsblwsfs 來自: 61.228.72.203 (01/09 09:25)
angelstar:fourier!!!!天啊~~~可怕的高微地獄~ 218.166.148.203 01/09
angelstar:這話題竟可以引起不同系的人的共鳴...||| 218.166.148.203 01/09