Finding the Angle of a Complex Number: Tips and Tricks

asi123
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Homework Statement



Hey guys.
I have the next transfer function

http://img195.imageshack.us/img195/7924/scan0002l.jpg

And I want to find the angle of it.
I know I can break it into REAL and IMAGINARY but I'm looking for a faster way, is there?

Thanks.

Homework Equations





The Attempt at a Solution

 
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asi123 said:
I have the next transfer function

And I want to find the angle of it.

Hi asi123! :smile:

Hint: if w R and C are all real, then the angle (phase) of 1 + jwRC is arctan(wRC) :wink:
 
asi123 said:
I know I can break it into REAL and IMAGINARY but I'm looking for a faster way, is there?

Not really; finding the real and imaginary parts here is fairly quick. Just multiply both the numerator and denominator by the conjugate of the denominator, then \phi=\arctan\left(\frac{\text{Im}[H]}{\text{Re}[H]}\right).
 
gabbagabbahey said:
Not really; finding the real and imaginary parts here is fairly quick. Just multiply both the numerator and denominator by the conjugate of the denominator, then \phi=\arctan\left(\frac{\text{Im}[H]}{\text{Re}[H]}\right).

For this on, but I'm asking in general.

Thanks.
 
tiny-tim said:
Hi asi123! :smile:

Hint: if w R and C are all real, then the angle (phase) of 1 + jwRC is arctan(wRC) :wink:

Ok, I don't see any logic in that.
This is not a homework question, I know the answer, why would you give me a hint?
Is there a rule how to get to the angle?

Thanks.
 
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