Convert Fraction to Polar Form: H(F) = 5/(1+j2piF/10)

In summary, the conversation is discussing how to rewrite the complex function H(F) = 5/(1+j2piF/10) in polar form, as a magnitude and phase. It is determined that the phase is -arctan(piF/5) and the resultant magnitude is sqrt(1+(2piF/10)^2). The final form of the function is H(F) = |5F| exp(-jpiF/10).
  • #1
amiv4
25
0

Homework Statement



H(F) = 5/(1+j2piF/10)

Rewrite in polar form, that is, in terms of magnitude and phase.

Homework Equations





The Attempt at a Solution



phase is the 2piF/10 but I'm not sure how I account for it being on the bottom of the fraction
 
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  • #2
[tex] \frac{ A \angle \theta}{B \angle \phi} = \frac{A}{B} \angle \theta - \phi[/tex]also "2piF/10" is not the phase, not even for the complex number in the denominator alone.

to find an angle, you think of it in terms of real and imaginary parts forming a right triangle on the unit circle. The angle is this:
[tex] \arctan\frac{Im(A \angle \theta)}{Re(A\angle \theta)} [/tex]
 
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  • #3
So I should convert the top and bottom to polar separately and then divide them?
 
  • #4
amiv4 said:
So I should convert the top and bottom to polar separately and then divide them?

we must be careful when you ask questions with so many undefined pronouns. If by them, you mean the magnitudes and if you meant "should i ... to find the resultant magnitude", then the answer is yes.

if you are talking about angles, however, the answer is no. you must subtract the denominator's angle from the numerator's angle to find the resultant angle.
 
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  • #5
k this is what i got

5[tex]\angle[/tex]0[tex]/[/tex]1.18[tex]\angle[/tex]32.14

but idk where the F goes
 
  • #6
amiv4 said:
k this is what i got

5[tex]\angle[/tex]0[tex]/[/tex]1.18[tex]\angle[/tex]32.14

but idk where the F goes

the f remains symbolically.

for example, the magnitude of the bottom vector is:
[tex]\sqrt{1^2 + (\frac{2piF}{10})^2}[/tex]
 
  • #7
and then I would do the arctan of those two things to get the angle, but I don't see how they are going to simplify. Cuz I have to use this answer. Is there a way I could get the answer into a form similar to this H(F)=|5F| exp(-jpiF/10)
 
  • #8
amiv4 said:
and then I would do the arctan of those two things to get the angle, but I don't see how they are going to simplify. Cuz I have to use this answer. Is there a way I could get the answer into a form similar to this H(F)=|5F| exp(-jpiF/10)

it doesn't need to simplify. it will be messy but correct. as for putting it in the form you've specified:

[tex] A \angle \theta = Ae^{j\theta}[/tex]
and your theta for the overall transfer function will be:
[tex]\theta = -\arctan \frac{\pi F}{5}[/tex]

the negative comes from 0 - stuff
 

FAQ: Convert Fraction to Polar Form: H(F) = 5/(1+j2piF/10)

What is the purpose of converting a fraction to polar form?

The purpose of converting a fraction to polar form is to represent a complex number in terms of its magnitude and angle, rather than its real and imaginary parts. This can make calculations and analysis of the number easier in certain situations.

How do you convert a fraction to polar form?

To convert a fraction to polar form, you can use the formula H(F) = |H(F)| * e^(j*theta), where |H(F)| represents the magnitude of the fraction and theta represents the angle in radians. The magnitude can be found by taking the absolute value of the fraction, and the angle can be found by taking the inverse tangent of the imaginary part divided by the real part.

Can a fraction in polar form be converted back to its original form?

Yes, a fraction in polar form can be converted back to its original form by using the formula |H(F)| * cos(theta) + j*|H(F)| * sin(theta), where theta is the angle in radians. This will give you the real and imaginary parts of the original fraction.

What is the significance of the j in the polar form of a fraction?

The j in the polar form of a fraction represents the imaginary unit, which is the square root of -1. It is used to denote the imaginary part of the fraction and is necessary to distinguish it from the real part.

In what situations would converting a fraction to polar form be beneficial?

Converting a fraction to polar form can be beneficial in situations where complex numbers are involved, such as in electrical engineering, signal processing, and physics. It can also make calculations and analysis of complex numbers easier in certain mathematical operations.

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