XE31CZS Exercise - Filtering in Frequency-Domain
Task to do:
- Signal preparation.
- Signals to be mixed:
- sinusoidal of following parameters A = 1, f = 49.5 Hz, fs = 200
Hz, to = 4 s
- Gaussian white noise of same length
- ECG - ekg1.asc (fs = 200 Hz, ASCII
format, to read into MATLAB buitl-in-function load)
- Create following mixtures:
MIX1: sinusoidal + white noise, SNR = 0 dB, 6 dB
MIX2: ECG + sinusoidal, SNR = 6 dB (harmonic signal is supposed to be disturbance)
- Filtering in frequency-domain
- Try to suppress noise in MIX1 using band-pass filter in band fd=48 Hz, fh=52 Hz.
- Realize the filtering in the frequency-domain using removing of
spectral components related to given frequency band.
- In the first step, realize the filtering for whole signal without
- In the second step, use the signal segmentation and generate
output signal using "overlap-and-add" algorithm.
- Evaluate SNR of output signal
- Repeat steps described above also for the case of suppression
harmonic noise in the signal MIX2 using frequency based band-stop
filter in the range fd=48 Hz, fh=52 Hz.
- Try to realize above frequency-domain filters in the time domain
(FIR, IIR) and compare the results from following aspects
- order of designed filter fullfiling given requirements
- achiev SNR in output signal
- Use impulse responses of designed filters (FIR, IIR) and try to realize these
filters in the frequency-domain using DFT.