All About Circuits Forum  

Go Back   All About Circuits Forum > Electronics Forums > General Electronics Chat

Notices

General Electronics Chat Discussion forum for general chat about anything electronics related, including asking questions about material in the All About Circuits E-book, Worksheets, and Videos.

Reply   Post New Thread
 
Thread Tools Display Modes
  #1  
Old 06-04-2011, 03:24 PM
atferrari's Avatar
atferrari atferrari is offline
Senior Member
 
Join Date: Jan 2004
Location: Buenos Aires - Argentina
Posts: 1,396
Default FFT in LTSpice

LTSpice

I am confused about this: what it is the actual reference (0 dB) as shown in the graphic of a FFT from a certain signal?

In other words, the level of the harmonic content, is it compared to what?
__________________
Agustín Tomás

In theory, there is no difference between theory and practice. In practice, however, there is
Reply With Quote
  #2  
Old 06-04-2011, 07:46 PM
debjit625's Avatar
debjit625 debjit625 is offline
Senior Member
 
Join Date: Apr 2010
Location: Blue planet...
Posts: 790
Default

Normally the FFT shows the result in decibel but you can change the unit to Volts or Amp,use "linear" option to repersent the magnitude.To, get the option window in LTSpice click on the decibel units on FFT window.

Good Luck
__________________
Debjit Roy
__________________
A man would do nothing,if he waited until he could do it so well,that no one would find fault with what he has done.
- CARDINAL NEWMAN
Reply With Quote
  #3  
Old 06-05-2011, 02:56 AM
Ron H's Avatar
Ron H Ron H is offline
E-book Developer
 
Join Date: Apr 2005
Location: Idaho, USA (GMT-7)
Posts: 7,050
Default

I ran a little experiment on a 1kHz sine wave. 1V RMS = 0 dB.
Reply With Quote
  #4  
Old 06-05-2011, 12:30 PM
atferrari's Avatar
atferrari atferrari is offline
Senior Member
 
Join Date: Jan 2004
Location: Buenos Aires - Argentina
Posts: 1,396
Default Grasping the basics

Yes Ron, I was suggested to do a FFT exactly on that. It is clear for me now.

Good Luck, thanks for your reply as well! Have to experiment with all that.
__________________
Agustín Tomás

In theory, there is no difference between theory and practice. In practice, however, there is
Reply With Quote
Reply   Post New Thread

Tags
,


Related Site Pages
Section Title
Worksheet Sum-of-Products and Product-of-Sums expressions
Worksheet High-reliability circuits
Worksheet Digital communication
Worksheet Digital display circuits
Worksheet Precise diode circuits
Worksheet Special diodes
Worksheet DC mesh current analysis
Worksheet Mixed-frequency signals
Textbook Square wave signals : Mixed-frequency Ac Signals
Textbook Introduction : Solid-state Device Theory


Similar Threads
Thread Thread Starter Forum Replies Last Post
LTspice NY10 General Electronics Chat 6 08-27-2010 02:53 PM
LTSpice - Missing user placed component after upgrade eblc1388 General Electronics Chat 0 04-09-2010 02:39 PM
Ltspice? Mathematics! General Electronics Chat 3 01-21-2010 09:19 PM
Experts of Lecroy scope, FFT, and MATLAB... pls assist! onemilimeter General Electronics Chat 2 12-22-2008 05:20 PM
Inverting opamp in LTspice swappo General Electronics Chat 0 05-11-2008 04:01 AM

Thread Tools
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off

Forum Jump


All times are GMT. The time now is 12:46 PM.


User-posted content, unless source quoted, is licensed under a Creative Commons Public Domain License.
Powered by vBulletin® Version 3.8.7
Copyright ©2000 - 2014, vBulletin Solutions, Inc.