# Questions tagged [bode-plot]

Anything related to Bode plots, i.e. a special graphical representation of the frequency response of a linear time-invariant system.

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69 views

### Visually determine pole from Bode plot

Currently I'm taking a basic electronics course and this was a part of homework. The Bode plot represents the frequency response of an amplifier and from this plot we had to determine the dominant ...
54 views

### Designing a bode diagram circuit

I have realized some low pass filters with a nominal cut off frequency around 10kHz, which I will use in combination with other filters to eliminate noise on DC and quasi-DC signals (around 30Hz). I ...
103 views

### Transfer function of an op amp with an Y or delta

What's the transfer function of the op-amp with a Delta from figure one? Such circuit can be easily converted into an Y, figure 2. Tina is calculating the transfer function from the Y circuit as H(s) =...
61 views

### How to find damping and the natural response in a system with a zero and complex pole pair

I want to know how to get damping and the natural response in a system with a zero and complex pole pair. I calculated the following transfer function: (from an active filter composed of 2 capacitors ...
53 views

### Identifying transfer function by its approximated graph

Consider the transfer function which is approximated graph is: I want to identify this function. As far as I can tell, since we see decreasing by $-20db/dec$ at $10^{-1}$, we can conclude that ...
54 views

### Is there a methodical way to desig multi-stage anti-aliasing filters?

Lately I've been thinking about the best approach to design multi-stage anti-aliasing filters in real-life. I know tools like Analog Filter Wizard or LTSpice can help to a certain extent, but they've ...
153 views

### Zero Order Hold Bode diagram

Here is the transfer function of the Zero Order Hold and its bode diagram: This transfer function is usually used for modelized a Digital to Analog Converter. Do you know why there is sharp roll off ...
70 views

### Why is the noise gain these opamps 500? I feel it should be 250

I wanted to check the bandwidth of the first stage of an instrumentation amplifier configuration and this is the circuit: Since, the noise gain of an opamp is (1+Rf/R1), for each of the op-amps the ...
792 views

### Is -3dB bandwidth defined for any type of transfer function?

If I have response like the following, is it still valid to say bandwidth of the circuit is 2.31kHz?
58 views

### Please help me clear up this confusion regarding gain margin and phase margin and unity feedback

I understand the physical significance of gain and phase margin. However, I would like some clarification regarding the mathematical aspects. Videos such as the following: https://www.youtube.com/...
99 views

### Preemphasis circuit, calculating H(s) and Bode plot

I have the following circuit: (which should represent a "new" design for preemphasis block in a FM transmitter circuit) I need to calculate the transfer function H(s) and draw a Bode plot. ...
35 views

### Phase lower than -180 when reaching unity gain, is it unstable or can we substract 360?

I am getting a phase of -434 degrees when reaching unity gain (0 dB point). The phase curve starts at 0 degrees, thus, can we consider that -434= -434+360= -74 degrees and the phase margin is of 180-...
39 views

### Bode Plot of Type 3 Compensator

I've designed a Type 3 compensator and wanted to see it's bode plot on matlab. Here is the transfer function of type 3 compensator: My values are: wp0=203 wp1=6657000 wp2=31400 wz1=5024 wz2=5024 The ...
33 views

### Which of the following methods tells Absolute stability & which method tells Relative Stability? Bode Plot, Routh Hurwitz, Root Locus, Nyquist PlotC

Which of the following methods tells Absolute stability & which method tells Relative Stability? I. Bode Plot ii. Routh Hurwitz iii. Root Locus iv. Nyquist Plot What i think is the following ...
73 views

### control system - is the gain positive or negative?

If the phase of a control system at high frequencies approaches to 0º then its gain K is negative. And if it approaches to -180º it gain is positive? Why is that? And how it works for low frequencies? ...
133 views

### How to find gain and phase margin from transfer function without Nyquist or Bode plot

Given transfer function L(s) as a ratio of polynomials of s, I know that we can find gain margin (GM) and phase margin (PM) by using a Nyquist or Bode plot. From a Nyquist plot: Find a point where ...
79 views

### flyback compensation design

This is the control stage circuit of flyback, I want to use SIMPLIS to measure the bode plot to prove a theory is matched to simulation, I use Mathcad to draw the bode plot, the SIMPLIS result should ...
511 views

### Finding resonant frequency or damping ratio from Bode Plot

I am working on a question where I have to estimate a transfer function from its bode plot. I plotted the asymptotes of this bode diagram, and was able to find out that this is 3rd order system with ...
44 views

### Plotting a Bode from a Transfer Function on Matlab

I need a bode plot for a transfer function from matlab which I never did before. I tried some examples but failed. How to do this on matlab? Here is the TF:
21 views

### How to calculate Nichols' chart contours?

Nichols grids show contours of constant closed-loop G(jw) magnitude for the associated open-loop transfer function L(jw) ...
117 views

### How to prepare observation table and plot frequency response of Butterworth Sallen-Key High Pass Filter

My assignment: Design and simulate a Butterworth Sallen-Key High Pass Filter with the, fc = 10 kHz. Prepare the observation table and plot the frequency response. My answer so far: I want know how ...
75 views

### Bode plot starting from 180?

This is an NMOS common source amplifier and I'm trying to calculate the Phase Margin, but it's starting from 180 instead of zero? dose it mean I have poles at the origin or it's very stable?
72 views

### Remove big valley in phase plot

I am working on a speed controller for a robot and it's for when the robot is balancing on its wheels. I am designing the controller as part of a project in a linear control design course. However, ...
64 views

### I am miscalculating the Asymptotic Bode Plot

hope you are all doing well. Right now I am dealing with a homework and I have transfer function and I need to plot the asymptotic Bode Plots of it. I am trying to plot the Magnitude Diagram right now,...
30 views

### Is there an alternative to GCV (generator control voltage) to synchronize frequency sweep measurements?

A friend is taking a course in electronics engineering and asked me for help reproducing a lab experiment in frequency sweep measurement techniques. Students build a small RC filter and use a function ...
59 views

### Underlying reasoning behind lead and lag nomenclature of compensation

If $0<z, \;p$, the Laplace transform transfer function $\frac{s+z}{s+p}$ constitute two distinct types of compensators. If we look at this schematic, $0<z<p$ (lead compensation) implies ...
670 views

### How are the -3dB point and the pole of an op-amp related?

I have been looking at AC frequency responses for op-amps and I was wondering how an op-amp's pole and the frequency at the -3dB point are the same? They both mark the location where the gain starts ...
176 views

### unstable systems with positive phase/gain margin

Open loop Phase/Gain margins provide information on how much margin the closed loop system have until it becomes unstable. In other words, how much you can increase the effective loop gain and or ...
142 views

### Bode plot of buck converter incorrect?

So this question is a bit related to my other question on using Pspice to get the required transfer function of the buck converter. Here in this circuit I'm trying to get the open loop transfer ...
137 views

### Don't understand this zero pole plot example

I'm reading a book (see figure 5-12) about (among other things) pole zero plots and there is an example I don't understand. For the schematics and formula below: it adds the following zero pole plots:...
114 views

### How to Make a bode plot of an inverting amplifier?

I am trying to create a bode plot of the open loop gain and the closed loop gain of an inverting amplifier using mathematica. I know the documentation of the bode plot in Mathematica (BodePlot[lsys]) ...
137 views

### Closed loop system stability with Bode

Stability of the closed loop system (with -1 feedback) can be assessed via Bode plot gain/phase margin analysis of its open loop system. How can one deduce stability of the closed loop system directly ...
66 views

### Why is the slope of the op amp graph 20 log (AB) in this application note

I am going through the following guide for op amps : http://web.mit.edu/6.101/www/reference/op_amps_everyone.pdf On page 87 (screenshot attached) there is a bode plot which has got me slightly ...
37 views

### VNA Measurement method questions

With the Bode100 from Omicron lab, it is possible to perform different measurement. There are two which I want to discuss. You can find the handbook here. These are : Transmission/reflection on page ...
38 views

### Confusion in cut-off frequency of LTI System

Why cut-off frequency is at (in figure given below) the frequency where $$|M(j\omega)|=0.707=1/√2(D.C gain)$$ But isn't cut-off frequency according to its definition should be at frequency where  |...
208 views

I've read that it is recommended to have 20 dB/Decade slope on the L(jw) magnitude plot of the Bode Diagram at gain crossover. This seems to imply a slope of -1 in dimensionless terms. However, what ...
79 views

### Vertical axis of the magnitude Bode plot

Why is the vertical axis in the magnitude Bode plot linear? I am confused because i know that if we want to obtain the magnitude Bode plot of the frequency response, we take the decibel value of the ...
61 views

### Nichols plot confusion

The transfer function is $F(p)=10/(p^2+2p+1).$ Using Wolfram Alpha, the Nichols plot shows that the argument $\to -\pi$ when $\omega \to +\infty$. However, calculating the argument on paper ...
259 views

### Recreate "Voltage gain vs Frequency" graph of Op-Amp in LT Spice

I am trying to recreate the "Voltage gain vs Frequency" graph of the LT1037 Op-Amp in LT Spice. According to the datasheet page 6 the graph looks like this: - Trying to recreate this in LT ...
242 views

### Infinite Phase Margin

I have been assigned a control systems problem, where I am supposed to stabilize a system using a controller technique from the frequency domain. When I implemented the system on Matlab and calculated ...
560 views

### How can a Bode plot be like that?

Can you do explain how to draw a Bode plot with GH(s)? How do I get the slope and intersection point? This is one of the teacher's examples. He drew it but I don't know what it means. Can you explain ...
77 views

### How would the pole and zero frequency expression look like for this transfer function I derived?

This is a practice problem in deriving the transition frequency function for mos and part of the set of questions is to determine the pole and zero frequency expression but this transfer function i ...
65 views

### Could somebody clarify the phase angle and gain of this transfer function?

Suppose a circuit with a transfer function of the form $A(\omega)=\displaystyle\frac{A_0}{1-\frac{j\omega}{\omega_0}}$ has $A_0=-10\; V/V$ and $\omega_0=100\;rad/sec.$ We were asked for the gain ...
83 views

### Oscillation frequency / criteria from Bode plot, negative feedback system

Got a question, which is very integral to a project that I am writing a report for (which I am to hand in soon, so in a hurry). Question: What will my oscillation frequency be? How will it be ...
77 views

### A question about negative phase angles in Bode plots

Looking at the phase Bode plot for the output of a filter as shown below: 1-) Taking the point -460° as an example, can we say that this is equivalent to +100°? 2-) Does that mean the output signal ...
1k views

### Why is frequency not measured in db in bode's plot?

While drawing bode's graph paper where Y axis is gain given in db while the X axis is frequency given in absolute value but scale used is log. I think the reason for log scale on X axis is to increase ...
113 views

### How is this pole compensated

I have an amplifier in a closed loop, the diagram looks as follows: The DC gain is simple which $-Rf/R1$. If I make $-Rf=2\cdot R1$ the the DC gain is two. This is verified using AC analysis ...
115 views

### How to find the total phase of this transfer function

I'd always understood that in a transfer function, every pole contributes -90 degrees in phase and every zero contributes +90 degrees in phase. Based on this assumption, I would expect the following ...