1. Filters What is a filter Spectral response Impulse response
Filter types
How to design/apply/use them

2. What is a filter? Extract desired components
Why? To extract information in a systematic way
Easily described in spectral terms
Lowpass
Highpass
Bandpass
Multiband
Notch
Reduce the intensity in region(s) of spectrum

3. dftlopass2demo(fs, timelen, b0, b1)

4. dftlopass2demo(fs, timelen, b0, b1)

5. dfthipass2demo(fs, timelen, b0, b1)

6. Impulse response Filter can also be represented in time domain
Impulse response is output when impulse is applied at input
DFT of impulse response is spectral response!
Very handy!

7. Filter types Finite Impulse Response (FIR)
an = 0
Non-recursive
Inefficient
Infinite Impulse Response (IIR)
an  0
Recursive
Efficient

8. How to design/apply/use filters
Usually design in spectral domain
Apply in either time or spectral domains
Depends on length of impulse response
Apply by mutiplying spectra
Add in dBs!
Convolve in time domain…
Often we need to estimate filter…