EE5410 Signal procesing 不要再說「和平、理性、非暴力」-- The frequency response of the first-order causal LTI system

EE5410 Signal procesing 不要再說「和平、理性、非暴力」-- The frequency response of the first-order causal LTI system

不要再說「和平、理性、非暴力」，要說「和平、理性、勇武」。面對恃勢凌人而不可理喻的暴政和強權，人民有動武之權。即使不是動刀動槍，也要堵塞暴政的齒輪，中止社會的營運秩序，令強權得到教訓，令市民得到覺醒。

1.Consider the first-order causal LTI system is described by the difference equation

y[n]- ay[n-1] = x[n], with |a |<1.

2. |a| determines the RATE at which the first-order system records.

3. for a >0, the system attenuates HIGH frequencies, while when a <0, the system amplifies high frequencies and attenuates LOW frequencies.

4. for |a| small, the maximum and minimum values, 1/(1+a) and 1/(1-a) of the frequency response are close together in value, and the graph is relatively FLAT.

5. for |a| near 1, these quantities differ significantly, and consequently it is more SHARPLY peaked, providing filtering and amplification that is more selective over a narrow band of frequencies.