Difficult Understanding Magnitude and Phase Shift of Transfer Function

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Discussion Overview

The discussion revolves around understanding the magnitude and phase shift of a transfer function, specifically how to derive these from the given equations in a textbook. Participants explore the mathematical manipulation of complex numbers involved in this process.

Discussion Character

  • Exploratory, Technical explanation, Conceptual clarification

Main Points Raised

  • One participant expresses difficulty in transitioning from the initial transfer function to the equations for magnitude and phase shift, questioning the logic behind finding the magnitude of the complex number in the denominator.
  • Another participant suggests that plotting complex numbers graphically may aid in understanding the denominator's role.
  • It is proposed that multiplying the numerator and denominator by the complex conjugate of the denominator can clarify both the angle and magnitude, which is described as a standard method for manipulating complex numbers.
  • A link to an external resource on complex analysis is provided for further reference.
  • A later reply acknowledges the insights and resources shared by others.

Areas of Agreement / Disagreement

Participants do not reach a consensus on the understanding of the transfer function's magnitude and phase shift, with some expressing confusion and others offering methods to clarify the concepts.

Contextual Notes

The discussion highlights potential gaps in understanding the mathematical steps involved in deriving the magnitude and phase shift, as well as the implications of the negative sign in the phase shift equation.

wellmoisturizedfrog
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TL;DR
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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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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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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Ah I see, thank you for the insight! I appreciate the insight and resources.
 
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