HOME  |  NEWS  |  BLOGS  |  MESSAGES  |  FEATURES  |  VIDEOS  |  WEBINARS  |  INDUSTRIES  |  FOCUS ON FUNDAMENTALS
  |  REGISTER  |  LOGIN  |  HELP
Blogs
Mechatronics Zone

FIR Filter Coefficients

NO RATINGS
1 saves
View Comments: Oldest First|Newest First|Threaded View
ttemple
User Rank
Platinum
DFT of coefficients
ttemple   9/6/2013 8:10:52 AM
NO RATINGS
Jon,

I didn't know that performing an FFT on the filter coefficients would produce the same characteristic as the filter.  That is interesting.  I have always used software to produce the coefficients, and somewhat trusted the output.  I do usually verify the overall gain by summing the coefficients, however.

It seems that the FFT output produced by 65 coefficients of 0.015625 is skewed by the zero padding.  I would expect the FFT of a constant value to have all energy content to appear in the 0Hz bin, and absolutely nothing in the other frequency bins.  By padding it out to 128 points with zeroes, you have essentially created a square wave with approximately a 50% duty cycle, and the FFT result looks like it (the odd harmonic content).

William K.
User Rank
Platinum
Designing an FIR filter, or any other kind of filter.
William K.   9/9/2013 10:45:24 AM
NO RATINGS
Since creating a filter design would be a very smal portion of my job activities, I would need to find some source of the design, either published or for sale. So presentations like this do wind up being a very useful resource on many occasions.

Partner Zone
More Blogs from Mechatronics Zone
Switched-capacitor filters have a few disadvantages. They exhibit greater sensitivity to noise than their op-amp-based filter siblings, and they have low-amplitude clock-signal artifacts -- clock feedthrough -- on their outputs.
This column wraps up our discussion of encoders with information about resolvers, which provide angular data over 360 degrees.
Engineers use rotary encoders to measure the angular position of an attached device or to measure distance indirectly.
The Machinist Calc Pro computes speeds and feed rates for milling, turning, and drilling: cutting speed, spindle speed, feed rate (inches/minute), cutting feed, etc.
Design News Webinar Series
7/23/2014 11:00 a.m. California / 2:00 p.m. New York
7/17/2014 11:00 a.m. California / 2:00 p.m. New York
6/25/2014 11:00 a.m. California / 2:00 p.m. New York
5/13/2014 10:00 a.m. California / 1:00 p.m. New York / 6:00 p.m. London
Quick Poll
The Continuing Education Center offers engineers an entirely new way to get the education they need to formulate next-generation solutions.
Sep 8 - 12, Get Ready for the New Internet: IPv6
SEMESTERS: 1  |  2  |  3  |  4  |  5  |  6


Focus on Fundamentals consists of 45-minute on-line classes that cover a host of technologies. You learn without leaving the comfort of your desk. All classes are taught by subject-matter experts and all are archived. So if you can't attend live, attend at your convenience.
Next Class: September 30 - October 2
Sponsored by Altera
Learn More   |   Login   |   Archived Classes
Twitter Feed
Design News Twitter Feed
Like Us on Facebook

Sponsored Content

Technology Marketplace

Copyright © 2014 UBM Canon, A UBM company, All rights reserved. Privacy Policy | Terms of Service