1 / 15

DIGITAL FILTERS

DIGITAL FILTERS. Box Car filter. Running Mean. Moving Average. M = 48. M = 49. M = 50. Impulse Response. Normalized SINC function windowed by the Lanczos window. M is the filter length (# of filter coefficients)  N is the sampling frequency = 2π/ Δ t

winter-walton
Download Presentation

DIGITAL FILTERS

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. DIGITAL FILTERS

  2. Box Car filter Running Mean Moving Average

  3. M = 48 M = 49 M = 50 Impulse Response

  4. Normalized SINC function windowed by the Lanczos window M is the filter length (# of filter coefficients) Nis the sampling frequency = 2π/Δt cis the cut-off frequency = 2π/Tc

  5. repeat wrap

  6. High-pass filtered : Original – Low-Pass

  7. Impulse Response Frequency Response (Fourier Transform of Impulse Response) Frequency Response or Admittance Function

  8. Low-pass: H 1 Pass Band Stop Band  0 c N

  9. High-pass: H 1 Pass Band Stop Band  0 c N

  10. Band-pass: H 1 Stop Band Stop Band Pass Band c2  0 c1 N

  11. Band-pass filtered 1) High-pass to cut-off the upper bound period (e.g. 18 hrs) 2) Low-pass to cut-off the lower bound period (e.g. 4 hrs)

  12. Gibbs’ Phenomenon H( ) Frequency Response or Admittance Function (Running Mean)  / N

  13. (  ) Lynch (1997, Month. Wea. Rev., 125, 655)

  14. Butterworth Filter q = 4 q = 10 q = 1 http://cnx.org/content/m10127/latest/

  15. Exercises http://www.falstad.com/dfilter/

More Related