What do you mean by 3 dB cutoff frequency? Why is it 3 dB,
not 1 dB?
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Answer Posted / john lam
A filter's cutoff frequency is generally defined at -3dB.
At this point, the voltage of the input has attenuated to
50%, or in power form 70.71%. After this point, the voltage
of the input will drop dramatically rendering it useless.
Therefore the -3dB point is picked as the cutoff frequency
point because of this nature. It's not chosen randomly.
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