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標題: Filter Group delay 和 step response關係 [打印本頁]

作者: s20192s20192    時間: 2014-3-12 11:26 PM
標題: Filter Group delay 和 step response關係
最近在看Filter相關書籍$ W2 n- D/ ^7 r/ `$ V, k
書中提到7 E; j/ U( `* w
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The time for the step response to reach the value 0.5 is an approximate measure of the average group delay; w9 M% C: x2 y) M3 x
and ringing in the step response indicates that the group delay varies strongly in the passband( Q, T2 [' k: E5 y8 P5 A
想請問為何從step response中就可以知道關於group delay
% W. S; a" |0 F( n7 a4 G! U0 F+ R0 C有什麼相關數學公式來驗證這些關係嗎: l% N2 ?+ q; v1 }' I
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voltage mode and current mode. S3 {& I- p/ F9 w# V" A
為何voltge mode較不適用在高頻阿) b) T7 e2 b/ v6 Z$ _7 u
書中是說voltage mode 用 feedback
' K! P! [. \7 ]* t( O5 N+ ]# q# {, C所以較不適用在高頻, N  A. \; T% _- ^9 S
但是用回授
- A3 m! v' M2 }  A0 Q& ?不是頻寬增加!?
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/ M6 f4 J, G! c1 s8 U想請教版上各位大大這兩個問題
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) \# [$ {2 M+ D5 s2 M7 d2 X9 G- B感謝
作者: s20192s20192    時間: 2014-3-13 12:12 AM
再多補充一個問題+ u2 w' N1 `+ A2 D: z
為何group delay (in passband)為何會隨頻寬減少而上升阿& x7 [9 k: F+ P

: v: A. `7 P) r/ I. f. h& ~3 s( B感謝




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