| 2.1.4 Oversampling
Sampling at rates greater than 2f
max
is called oversampling. One of the benefits of oversampling
is that the copies of F(f) that are present in F
s
(f) become increasingly separated as the sampling
rate is increased beyond 2f
max
. For an analog signal with a given frequency content and a given
anti-aliasing filter with a cutoff frequency of f
c
, sampling at two times the cutoff frequency
produces a certain amount of distortion due to spectrum overlap. When sampling at a higher rate,
a simpler anti-aliasing filter with a more gradual transition from passband to stopband and less
stopband attenuation can be used without any increase in the distortion due to spectrum overlap.
Therefore, oversampling can minimize the requirements of the anti-aliasing filter. The tradeoff,
of course, is that faster ADCs are required to digitize relatively low frequency signals.
7
Chia sẻ với bạn bè của bạn: | 
