Difficult Understanding Magnitude and Phase Shift of Transfer Function

  • #1
wellmoisturizedfrog
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1
TL;DR Summary
I am unsure if my current understanding of transfer functions is correct.
Hello,

My textbook offers the following transfer function as an example.

1701556509480.png


It then goes on to explain that the following equations represent the magnitude and phase shift of the transfer function.

1701556549125.png


However, I am having some difficulty jumping from the first equation to these equations. From my understanding, in order to find the magnitude of the transfer function, the magnitude of the complex number in the denominator is found. I'm not sure if this logic is correct.

I am also unsure about how the equation for the phase shift of the transfer equation has a negative sign in front. I understand the other aspects of it, though.

I would appreciate any clarifications.
 
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  • #2
Plotting the complex numbers graphically may help you understand why the denomiator is that way.

Multiply numerator and denominator by complex conjugate of denominator should help understand the angle.
 
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  • #3
scottdave said:
Multiply numerator and denominator by complex conjugate of denominator should help understand the angle.
And the magnitude as well......this is the standard way to manipulate complex numbers.
 
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  • #5
Ah I see, thank you for the insight! I appreciate the insight and resources.
 
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Related to Difficult Understanding Magnitude and Phase Shift of Transfer Function

1. How do I calculate the magnitude of a transfer function?

To calculate the magnitude of a transfer function, you can use the formula: magnitude = sqrt(real^2 + imaginary^2), where real is the real part of the transfer function and imaginary is the imaginary part.

2. How do I calculate the phase shift of a transfer function?

To calculate the phase shift of a transfer function, you can use the formula: phase shift = arctan(imaginary/real), where real is the real part of the transfer function and imaginary is the imaginary part. Make sure to convert the result from radians to degrees if necessary.

3. What is the significance of magnitude and phase shift in a transfer function?

The magnitude of a transfer function represents the gain of the system at different frequencies, while the phase shift represents the time delay between the input and output signals. Understanding these parameters helps in analyzing the behavior and stability of the system.

4. How can I interpret the magnitude and phase shift plots of a transfer function?

In a magnitude plot, peaks indicate resonant frequencies where the system amplifies certain frequencies. In a phase shift plot, changes in phase indicate time delays between input and output signals. Analyzing these plots helps in designing and tuning control systems.

5. What are some common challenges in understanding magnitude and phase shift of transfer functions?

Some common challenges include interpreting complex numbers, understanding the relationship between magnitude and phase shift, and visualizing the behavior of the system based on these parameters. Practice and familiarity with mathematical concepts can help in overcoming these challenges.

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