This is a topic that many people are looking for. thevoltreport.com is a channel providing useful information about learning, life, digital marketing and online courses …. it will help you have an overview and solid multi-faceted knowledge . Today, thevoltreport.com would like to introduce to you How to Make a Bode Plot Using MATLAB. Following along are instructions in the video below:
hi in this video Id like to show you how to make a bode plot using MATLAB heres a sort of blank template Ive prepared before I started the video to begin with just close everything clear clear your workspace and heres the transfer function that well be using everything in green is a comment if youre new to MATLAB so its not part of the program G of x equals 2 over X plus 1 this is the transfer function that Id like to obtain a bode plot for so first tell MATLAB what the numerator is these brackets indicate a matrix the numerator is 2 and now for the denominator start with the highest power of s thats as the first power in this case after it went up to s to the 100th power we choose s and take the coefficient here the coefficient on s is 1 space and the coefficient on s to the 0 the next lowest power is also 1 to put
1 here define some variable to hold the transfer function say equals and assign it this transfer function TF thats built-in function inside MATLAB and give it the numerator and denominator next we use the bode command to plot the transfer function that we just defined and turn the grid on with using the word grid and start the program heres our pot but first look here you can see it is the transfer function that we wanted we can verify that here and its a continuous time transfer function okay and now lets look at the actual plot so a couple of things to notice here first of all take a look at the beginning value notice that it starts out at roughly 6 and how can we tell by looking at the transfer function but it should be starting yet well if you take the magnitude when Omega is zero now what you would have here is just 2 over 1 if s is equal to J
Omega so 2 over 1 is 2 so 2 and Omega is 0 so I dont see to hear that you want it down here thats because were in decibels so to convert what you would do is put 2 and take the log of that value and multiply by 20 and now youre in decibels roughly 6 decibels so now that makes more sense we are at about 6 decibels here next thing the notice is whats called the break point break points will be located at wherever you have a pole or 0 in this case we have a pole essentially a zero in the denominator if youd like to call it that here at s equals negative 1 so our break frequencies at 1 radians per second and that will be located at 10 to the 0 10 to the 0 is 1 so we know that where this point is now Ill show it to you here on the graph its right here this is
our break point and next take a look at how the magnitude decreases after you go beyond the break point this is because its a pole if it was a zero it would be increasing instead and it actually decreases an exactly in 20 DB per decade he converted very um verify that this is the case move along another decade to right here youll notice that its moved from roughly 5 to negative 15 thats a difference of 20 move one one decade youre down here you move from negative 15 and negative 35 roughly thats another 20 decibels in one decade so that checks out okay next lets look at the face the phase starts at zero and a rule of thumb is that the phase will start at zero if the strands for function is positive which it is or it would start out at 180 degrees if it was negative then it starts to decrease it decreases at negative 45 degrees between this point and
this point the break point and one decade before the break point decreases roughly 45 degrees and it does this again by the end of the plot if it was a 0 instead of a pole it would be increasing as a general rule of thumb it would be steeper with more poles and now a intuition for what this plot means first looking at the magnitude plot this means for this region here this region the output is roughly twice the input at the zero point right here theyll be equivalent in magnitude no increase and then it starts to the output tends to be less than the input the phase is talking about the leg at the beginning the input and output are in sync zero phase but eventually the output legs behind the input until its at negative 45 degrees at the breakpoint and here at negative 90 degrees now at the end of a pot and this is how you make a bode plot using that
MATLAB, bode, plot, system, controls, frequency, response
Thank you for watching all the articles on the topic How to Make a Bode Plot Using MATLAB. All shares of thevoltreport.com are very good. We hope you are satisfied with the article. For any questions, please leave a comment below. Hopefully you guys support our website even more.