- #1
bobbyk
- 39
- 0
It is well-known that the step-response of an ideal low-pass filter (Gain = 1 for f = 0 to F and = 0 for f = F to infinity) is non-causal, in that the output appeares before t = 0.
But what if the filter's Gain is = 1 for f = 0 to F and = e (some small non-zero value) for f = F to infinity? Then the Paley-Wiener criterion for realizability is satisfied, and the output must be causal. What then is the output?
But what if the filter's Gain is = 1 for f = 0 to F and = e (some small non-zero value) for f = F to infinity? Then the Paley-Wiener criterion for realizability is satisfied, and the output must be causal. What then is the output?