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Unformatted text preview: Signal Processing-II Processing- 20 10 Derivative-based operators to remove low-frequency artifacts
• Derivative operator in time-domain
– Removes parts that are constant – Large changes in the input -> high values in the output • Boost HF components and suppress LF
components Dr. Bülent Yılmaz Bü BME402: Biomedical Signal Processing-II Processing- 21 Derivative operator
• d/dt -> multiplication by jw or j2*pi*f • Gain of the freq response, H(w)=jw
– starts with 0 and increases linearly • Second-order derivative operator d2/dt2
– H(w) = -w2 – Quadratic increase in gain for HF components Dr. Bülent Yılmaz Bü BME402: Biomedical Signal Processing-II Processing- 22 11 First-order difference operator
• y[n]=(1/T) [x[n]-x[n-1]] [x[n]- x[n• H(z)=(1/T) [1-z-1] [1• H(w)=(1/T) exp( -jw/2) exp( jw/2) • •
[2j*sin(w/2)] |H(w)|=(2/T) |sin(w/2)| Phase = pi/2 – w/2 • HF noise will be amplified
– Noise-amplification Noiseproblem Dr. Bülent Yılmaz Bü BME4...
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This note was uploaded on 06/11/2012 for the course ENG 411 taught by Professor Cca during the Spring '12 term at Istanbul Universitesi.
- Spring '12