In this experiment, it is observed that from the plots of the noisy
signal in frequency domain, we see that the noise is
located at the high frequency section of the original signal. Therefore,
an implementation of a lowpass filter would be
appropriate to block the noise of the signal. As observed, the stopband
edge frequency is chosen to be 2000Hz while
the passband is chosen to be 1500Hz.
The filtered signal sound has less treble as compared with the original
signal. In other words, it sounds softer. As was
This is caused by attenuation. However, the noise has been filtered
out... which is our main objective.
After calculating the SNR values for the noisy and filtered signals,
we can conclude that the higher SNR value of the filtered signal, contains
less noise than the noisy signal.
CONCLUSION
We can conclude that the IIR filter is much preferable than the FIR
filter as it is technically more
computation efficient. Moreover, the linearity in the phase response
of most practical digital filter is not an issue, making
the IIR filter preferable than the FIR filter.
The IIR filter has a sharper transition between passband and stopband
compared to the the FIR filter. So, the
filtered signal is more precise. We can eliminate the noise more effectively
with the IIR filter. Also, the IIR filter is
no so complex as the FIR when it comes to calculations. Therefore,
it is more computation efficient.
The output sound quality by the IIR filter is better than of the FIR
filter. The filtered signal is closer to the original
signal which is without the noise.