Find the transfer function for this signal flow graph

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Discussion Overview

The discussion revolves around finding the transfer function for a signal flow graph using Mason's method. Participants explore different approaches to solving the problem, express uncertainties about the methods used, and suggest software tools for assistance.

Discussion Character

  • Homework-related
  • Debate/contested
  • Technical explanation

Main Points Raised

  • One participant expresses uncertainty about their application of Mason's method and requests help using software for a quicker solution.
  • Another participant corrects the first by stating the name is Mason and suggests that the method used is incorrect, proposing specific adjustments to the transfer function calculations.
  • Some participants emphasize the importance of labeling edges to identify paths and loops clearly, noting that this can be tedious.
  • There is mention of a software called freeMASON that could assist with the calculations, along with suggestions that other software like Mathematica or Maple might also be useful.
  • Multiple participants express a desire for a definitive answer, indicating frustration with the complexity of the problem and the calculations involved.

Areas of Agreement / Disagreement

Participants do not reach a consensus on the correct method or solution. There are competing views on the application of Mason's method and the adjustments needed for the transfer function calculations.

Contextual Notes

Some participants note the difficulty in identifying paths and loops, which may affect the clarity of the calculations. There are unresolved aspects regarding the application of Mason's method and the specific software tools mentioned.

dat
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Homework Statement


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Homework Equations


Manson method

The Attempt at a Solution


I used Manson method. I am not sure this is the best result. can someone use MATLAB or some software to solve this quickly ??
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I think the man is called Mason, and sorry: I think you are your method is wrong.

Now, if you number the points from x to y: 1 . . 6, the transfer function from 1 to 2 seems to be 1. But later you will have a problem with the W4 from 1 to 3. You must move this W4 connection from 1-3 to 1-2. You can do this if you substitute the W4 by W4/W1, so that the new 1-2 function becomes 1 + W4/W1.

In the same way you must move the W5 function from 3-5 to 4-5, so that the new 4-5 function becomes
1 + W5/W2. So now the 2-3 and 3-4 loops in series have been made nice and clean.

You will have to do some more movements, to unfasten the loops, but I hope you understand the "system". Having done so, the rest of the problem is Mason's.
 
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My general comment is that the first thing to do is to label the edges so that all forward paths and loops can be clearly identified. Then do the substitutions in each clearly identified path. As far as I can see, the forward path gains and the loop gains make sense. But it is very difficult to identify the paths being calculated and I got tired of looking at it.
I am not aware of any software package that helps these calculations except one called freeMASON by Nikolai Schwerg https://www.radioeng.cz/fulltexts/2012/12_03_0892_0897.pdf The formula manipulations are equivalent to some standard matrix calculations, so there may be some software like Mathematica or Maple that would help.
 
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Hesch said:
I think the man is called Mason, and sorry: I think you are your method is wrong.

Now, if you number the points from x to y: 1 . . 6, the transfer function from 1 to 2 seems to be 1. But later you will have a problem with the W4 from 1 to 3. You must move this W4 connection from 1-3 to 1-2. You can do this if you substitute the W4 by W4/W1, so that the new 1-2 function becomes 1 + W4/W1.

In the same way you must move the W5 function from 3-5 to 4-5, so that the new 4-5 function becomes
1 + W5/W2. So now the 2-3 and 3-4 loops in series have been made nice and clean.

You will have to do some more movements, to unfasten the loops, but I hope you understand the "system". Having done so, the rest of the problem is Mason's.
I understand what you mean, your method is the first method I learned. I can solve this problem by only doing your method, not using Mason method. But Mason method I had used is the faster way to solve and it assume that you don't have to simplify the graph.
 
Hesch said:
I think the man is called Mason, and sorry: I think you are your method is wrong.

Now, if you number the points from x to y: 1 . . 6, the transfer function from 1 to 2 seems to be 1. But later you will have a problem with the W4 from 1 to 3. You must move this W4 connection from 1-3 to 1-2. You can do this if you substitute the W4 by W4/W1, so that the new 1-2 function becomes 1 + W4/W1.

In the same way you must move the W5 function from 3-5 to 4-5, so that the new 4-5 function becomes
1 + W5/W2. So now the 2-3 and 3-4 loops in series have been made nice and clean.

You will have to do some more movements, to unfasten the loops, but I hope you understand the "system". Having done so, the rest of the problem is Mason's.
oopss
 
FactChecker said:
My general comment is that the first thing to do is to label the edges so that all forward paths and loops can be clearly identified. Then do the substitutions in each clearly identified path. As far as I can see, the forward path gains and the loop gains make sense. But it is very difficult to identify the paths being calculated and I got tired of looking at it.
I am not aware of any software package that helps these calculations except one called freeMASON by Nikolai Schwerg https://www.radioeng.cz/fulltexts/2012/12_03_0892_0897.pdf The formula manipulations are equivalent to some standard matrix calculations, so there may be some software like Mathematica or Maple that would help.
can you just put the graph in the software and find the tranfer funtion to get the result ?? I only want to know the right answer
 
dat said:
can you just put the graph in the software and find the tranfer funtion to get the result ?? I only want to know the right answer
Sorry, I have never used that software and don't have it.
 
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FactChecker said:
Sorry, I have never used that software and don't have it.
thank you for your concern
 

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