Bode Definition and 103 Threads

  1. F

    Bode plots and crossover frequency

    Below are a couple of problems given, 3 and 4. They are about drawing bode plots based on a given transfer function. I am wondering if anybody could please let me know if I drew the Bode plots right or wrong? Also I am not sure about how to find the crossover frequency. On task 3 I calculated it...
  2. S

    Gain bandwidth product from bode plot

    Can anyone tell me how to find the gain bandwidth product from bode plot of a unity gain circuit for the attached bode plot? I hv attached the circuit and bode plot ...
  3. H

    MATLAB Matlab: Butterworth Filter Bode Plot

    I'm stuck on a really simple problem because I haven't done MATLAB in a while. I have transfer functions for nth order lowpass Butterworth Filters: H(jw) = 1/(s + w_c)^n I want to plot the 1st to 5th order filters. How do I input H(jw) into matlab? The tf(num, den) is not efficient in that...
  4. D

    How to find cutoff frequencies from Bode plot?

    Homework Statement http://img832.imageshack.us/img832/7517/captureax.jpg According to the solution, the cutoff frequencies are 1, 20, 80, 500 and 8000. I don't understand how to get those answers by inspecting the plot. Homework Equations None The Attempt at a Solution I think the...
  5. D

    Get transfer function from bode plot

    Homework Statement What is the transfer function described by this bode plot: http://img96.imageshack.us/img96/4775/capturegib.jpg *The answer is 3s, but I don't know where it comes from. Homework Equations None The Attempt at a Solution Correct me if I am wrong. A bode plot is a...
  6. C

    Why Does the Bode Plot of a Type 1 System Show a Damped Slope Initially?

    For a transfer function of G(s) = 100 / (s(s+5)), I'm having trouble finding the initial magnitude in dB. It's a type 1 system. If it was a type 0 system with only (s+5) in the denominator, the initial magnitude would be 20log(nominator/denominator) where s is an element of 0, and would decrease...
  7. M

    Why Does My Bode Plot Phase Shift Differ from My Friend's?

    Homework Statement I have the transfer function: for the circuit: The component values are know, and are: R1 = 47kΩ R2 = 4K7Ω C = 10nF Homework Equations The Attempt at a Solution I have derivied the transfer function but have become stuck on plotting the bode plot. I understand...
  8. C

    What are the characteristics of a second order bode plot?

    What is the difference between second order zero bode plot and second order pole bode plot?
  9. R

    MATLAB Plotting Bode Diagrams with Exponential & Complex Transfer Functions

    Hi there, I'm having a hard time trying to plot a Bode Diagram here in MatLab. The transfer function not only has an exponential function in it, but also has 3 unknowns to which I am not supposed to assign value, and on top of that it is a complex number. Let me write it down to you...
  10. N

    Magnitude and Phase Bode Plot Help

    Hi all, on a current homework I have been given a transfer function and asked to draw the straight-line (asymptotic) magnitude (dB) and phase (degrees) Bode plot. I first learned Bode plots roughly a year ago, and while being on spring break and my notebook from last year is at school, I'm...
  11. kandelabr

    What is the meaning of positive phase in a bode plot?

    Homework Statement I have a bode plot with a positive phase. Homework Equations this is a MATLAB code for the thing % bode phase plot w = logspace(1, 4, 100); G = 100*(1+0.017i*w)./(1i.*w.*(1+0.05i.*w).*(1+0.0025i.*w).*(1+0.001i.*w)); fi = atand(imag(G)./real(G)); semilogx(w, fi); % x-axis...
  12. P

    Bode Plot - Calculating ωgc and ωpc analytically

    I am learning to draw Bode Plots. I am able to figure out ωgc, ωpc, Phase Margin & Gain Margin graphically from the Bode Plot. But I was wondering if there is a way to calculate ωgc and ωpc mathematically with some formulas - how do I do this?
  13. P

    Bode Plot - why 20log instead of 10log

    Since the deci in decibels means 10, why is decibels of Magnitude in the Bode plot calculated as 20log instead of 10log?
  14. J

    Bode plot normalization process

    Hi, I have a 8th order s-domain transfer function that i would like to normalize for plotting a bode plot. The transfer function is in expanded form i.e. s^8 +s^7+s^6 etc. i want to normalise the frequency f by frequency f0 such that s = j(f/f0) instead of just s = j2πf. the reason i...
  15. A

    Creating a Bode plot by analyzing a transfer function

    Homework Statement I am constructing a Bode plot from a given transfer function. I having trouble because I am unsure how to rewrite the transfer function in the proper form. What makes this transfer function particularly tricky for me, is that there is no "jω" in the numerator, just ω^2...
  16. D

    MATLAB Making Bode Plots with GUI in MATLAB

    Hello guys! I have an issue, I'm trying to make a program in which you can get a bode plot by knowing the transfer function in guide. The basic idea is this: you enter 4 numbers in the interface and by those numbers you can know the transfer function, basically I'm doing this as a final step...
  17. K

    Plotting Bode Magnitude & Phase Plots By Hand

    How would you plot the magnitude and phase Bode plots for the system transfer function of (4s^3+40s^2)/(4s^4+405s^3+504s^2+400s) I plugged it into MATLAB and got a result but my professor wants hand calculations. Thanks
  18. D

    How Do You Construct Bode Plots for Cascaded CR Networks?

    Homework Statement Question attached Homework Equations Frequency response of circuit given in document The Attempt at a Solution The question leads me to find the Gain and phase of the gain, pole and zero terms. The breakpoint frequency and the point where the gain term is 0db...
  19. J

    Bode Plot Question(Phase and Gain Margin)

    I have been drawing a few bode diagram by hand and i am ask to find the phase and gain margin of the plot. Can someone please explain what are phase and gain margin, including how to determine it from the bode plot?
  20. J

    Creating Bode Plot: Problem Determining Break Off Frequencies

    I am trying to manually make a bode plot for the transfer function: G(jw)= 5/[jw(1+jw0.6)(1+jw0.1)] I know how to plot it but I am having a problem determining all the break off frequencies. In particular for the term pole at (1+jw0.6). Could someone give...
  21. T

    Drawing a Frequency-Magnitude (Bode) Plot: Thomas's Questions

    I need to draw a frequency- magnitude (bode) plot of this circuit: Firstly I need to find the RC but I don't have a clue. It's meant to be 1ms, and I guess that's from 10k * 100nF BUT why is the 20K not involved? Thanks Thomas
  22. J

    MATLAB Exploring Matlab Step, Impulse, and Bode Functions in Physical Systems

    So I understand what these inputs are, however I'm having a hard time visualising what they do in a physical system. Can anyone share any physical examples of what each of these do? E.G I assume a step input in a Mass Spring Damper system would create the force to cause oscillation?
  23. S

    Why Are My Bode Plot Results in MATLAB Different from LTSPICE?

    Homework Statement I'm working on a Lab for my Electronics Course and need to use MATLAB to create a Bode Plot to get the data for my theoretical Magnitudes at frequencies between 50Hz and 500 Hz. The Resistor has a value of 1k and the Capacitor has a value of 1uF. I need one for both a high...
  24. M

    Effect of Poles & Zeros on the bode plot

    Homework Statement What are the effects of poles and zeros of a transfer function on its magnitude graph. Note: The Transfer function is discrete. Homework Equations zeros= roots of numerator poles=roots of denominator The Attempt at a Solution I really don't have any idea. I...
  25. R

    Phase and Bode Plots: Struggling to Understand High-Pass Filters

    Homework Statement I am really struggling to understand how to draw a phase plot for circuits such as low/high-pass filters and other LCR circuits. I understand how to find the gain and use this information to make a Bode plot but when it comes to phase I just don't even know where to begin...
  26. S

    Frequency Plot(or bode plot) in SIMULINK

    Dear all, Can anyone describe as to how we can plot frequency response in SIMULINK-MATLAB. One way is to use spectrum analyzer but it does not give accurate results for continuous time systems...another way could off course be to use commands but I need something which can compute bode plots...
  27. R

    Control problem. Transfer function given. Sketch Bode plot

    1. For the control system described by the transfer function H(s)=Y(s)/U(s)=10/(s^2+11s+10) Sketch the bode plot: amplitude and phase diagram. What is the bandwidth of the system? 2. General form of a second order system H(s)=wn^2/(s^2+2*zeta*wn*s+wn^2) Magnitude characteristic in...
  28. M

    Bode Plot Question: Homework Statement & Solution Analysis

    Homework Statement I'm doing a question that requires a Bode plot (magnitude and phase). The Attempt at a Solution I got a transfer function of H(\omega)=\frac{1+\frac{j*\omega}{3}}{1-0.1667(\omega)^{2}+0.4167j*\omega} So there is a simple zero at 3 rad/s; complex pole at 2.45 rad/s...
  29. V

    Control Systems: Frequency response Bode plots and analytical expressions

    Homework Statement Find analytical expressions for the magnitude and phase of the frequency response for each G(s) below: (a) G(s)\,=\,\frac{20}{s\,\left(s\,+\,5\right)\left(s\,+\,5\right)}(b) G(s)\,=\,\frac{2\,\left(s\,+\,5\right)}{\left(s\,+\,1\right)\,\left(s\,+\,10\right)}(c)...
  30. M

    Bode Plot problem (Please check my work )

    Bode Plot problem (Please check my work :)) Homework Statement This is actually a circuits question. It required to find Vo(s) in a network with Vi(t) being 1V (so Vi(s) was 1/s). It then asked to plot the magnitude of Vo for a range of frequencies (from 100 to 1000Hz). The Attempt at a...
  31. S

    How Do You Determine Gain and Parameters from a Bode Plot?

    Homework Statement Transfer function: G(s) =\frac{k}{s^{2}+2\varsigma\omega_{n}s+\omega_{n}^{2}} a) if u(t) = cos(2t), find the steady state response b) determine the values for k, damping ratio (\varsigma), and the natural frequency. Homework Equations The Attempt at a Solution...
  32. T

    MATLAB Creating Bode Plot in MATLAB - Tieske90

    Hi everybody, I did a few measurements at a printer. I have a signal that i put in the printer that gives the printerhead a speed. I have put a sinus on the printerhead, and did this at different frequencies with the same signal strength (20 to 500 Hz, with steps of 15 Hz). I want to...
  33. R

    Help with Bode Plots | Gain Calculation

    Hey, could some one please help me with bode plots. I have a transfer function,lets say G(s)=0.16s/(1+0.16s) if I want to find the gain at 10 rads/s, do I subsitute s for 10 and then take 20log( G(10) )? Thats what I thought the method was, but now in my notes it says, Gain = 0.16ω/√(1...
  34. C

    Drawing a Bode Plot w/ Equation Example

    Homework Statement How do you draw a bode plot? I have a simple equation: H(S)=s+10 but no school book. Can you help me understand?
  35. C

    How to Draw a Bode Plot Without a School Book

    Homework Statement How do you draw a bode plot? I have a simple equation: H(S)=s+10 but no school book. Can you teach me?
  36. G

    Draw a bode and nyquist diagrams

    I have a task to draw a bode and nyquist diagrams from an expirmential results by using MATLAB, I have the phase delay and the votage gain data (10 results for each), can you help me how to darw bode and nyquist diagrams in MATLAB and which command I can use? thanks
  37. G

    Bode & Nyquist diagrams from expirmental results

    Hi I have a task to draw a bode and nyquist diagrams from an expirmential results, I have the phase delay and the votage gain data, can you help me to darw bode and nyquist diagrams? Thanks
  38. G

    What are the benefits of Nyquist and Bode diagrams?

    Hi I want your help to understand the comparative merits of Nyqist and Bode diagrams, if you can explain that merits to me? Thanks
  39. B

    Bode Phase plot of a second order system

    Hey guys. I need to know how to draw a Phase Bode plot of a Second order system. I understand and can draw the Gain(Magnitude) Bode plot, but I can't seem to get the grip of the Phase one. As far as I know there is an asymptote at 0^{o} at low frequencies and an asymptote at 180^{o} at...
  40. maverick280857

    Question regarding Gain/Phase Margins and Bode Plots

    Hi While going through http://eprints.iisc.ernet.in/archive/00013500/01/lec_6_web.pdf, I came across the following two statements (on page 3), for a system with loop gain = G(s)H(s): 1. Open GH loop must be stable for designing via Bode Plots. 2. If for GH, gain crossover < phase...
  41. F

    Drawing Bode Phase Plots: Real Poles & Zeros in RHP

    Well, it has been awhile... and I need to remember how to draw a Bode phase plot quickly. The problem I am having is, how do I deal with real poles and zeros in the right half plane? I can quickly draw bode phase plots for transfer functions like: H(s) =...
  42. D

    Sketch Bode Plot for G(s)=10/s(1+ts)

    Homework Statement Sketch the Bode Plot for the following Transfer Function: G(s)=10/s(1+ts) where t=0.1sec The Attempt at a Solution G(jw)=10/jw(1+tjw) - frequency response... Gain = 20log(10) - 20log(tw^2+w) Does this mean that the Gain apporaches infinity as w approaches...
  43. J

    Drawing Bode Plots: Tutorials & Examples

    Any good online pdf files or websites with examples on how to draw bode plots?
  44. B

    How Do I Plot a Bode Plot for a Given Transfer Function?

    hi, how can i plot the bode plot for this transfer function: 100 ---------------- s^2 + 10s + 100 i have 2*ksi*w=10 w=sqrt(100)=10 thus, ksi=1/2 -ksi*w=-10/2=-5 so the overshoot will be at ksi which is at 1/2 and my magnitude is 1. i don't see how i can find my...
  45. tandoorichicken

    Bode Plots: Plotting Homework Statement

    Homework Statement I have to plot some data for a lab writeup. It's based on the frequency response of fluid catheter-transducer systems. Part of this writeup includes making Bode plots for the gain and phase shift. I know how to plot my data; the problem that I am having is that I want to try...
  46. V

    Drawing Bode plots: I need to convert to s-domain - but how?

    Homework Statement The question asks the reader to make a Bode plot for the following equation: H(\omega)\,=\,\frac{50\left(j\omega\,+\,1\right)}{j\omega\left(-\omega^2\,+\,10j\omega\,+\,25\right)} Homework Equations j\omega\,=\,s The Attempt at a Solution...
  47. N

    Engineering Circuits: Bode Plot for Frequency vs. Voltage Gain | Homework Help Statement

    Homework Statement sketch a bode plot of frequency versus voltage gain (in decibels) for the following circuit: Homework Equations Voltage divider: V_X = V_S \frac{Z_X}{Z_T} Voltage gain: A_V = \frac{V_O}{V_I} log(A)+log(B) = log(A*B) The Attempt at a Solution This is the most...
  48. B

    MATLAB Why Does My Z-Transform Bode Plot Show Incorrect Amplitude for a Sine Wave?

    Hi, I try to visualize a sine wave, z-transformed in a Bode plot. The frequency shows up correctly, but the amplitude is way off - why? Thanks for your comments. Bmalp function zdemo format compact syms w Ts n z phi t Ts = 1 w = 0.1 phi = 0 vz =...
  49. F

    Bode Plots - phase plotting by hand

    My notes from lecture are somewhat deceiving. I have this table that is supposed to make plotting the phase portion of a Bode plot simple. I understand the magnitude portion, however I do not get what is being said for the phase portion. I am spending too much time on something that is supposed...
  50. M

    Understanding the Bode Plot: Frequency vs. dB

    Is the x-axis of a Bode plot supposed to be angular frequency omega or just the frequency f? The y-axis is in dB. Thanks!
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