Continue to Site

Welcome to EDAboard.com

Welcome to our site! EDAboard.com is an international Electronics Discussion Forum focused on EDA software, circuits, schematics, books, theory, papers, asic, pld, 8051, DSP, Network, RF, Analog Design, PCB, Service Manuals... and a whole lot more! To participate you need to register. Registration is free. Click here to register now.

Register Log in

Tan and ArcTan calculation

Status
Not open for further replies.
B

baby_1

Advanced Member level 1
Advanced Member level 1
Joined
Dec 3, 2010
Messages
415
Helped
1
Reputation
2
Reaction score
1
Trophy points
1,298
Activity points
4,277
Hello
Could you help me to solve this problem? i want to find w
71_1340528592.gif
 

Hello Baby_1

the answer is w=10000*sqrt(230).

Hope helps.

Cheers
 
  • Like
Reactions: baby_1

    B

    baby_1

    Points: 2
    Helpful Answer Positive Rating
By trial and error, w = about 154000
I have no idea how to calculate it. What's this for?
 

This looks like the start of a phase margin calculation.

Usually trail and error or plot it in MATLAB and read it off or use MATLAB's solve functions.
 
  • Like
Reactions: baby_1

    B

    baby_1

    Points: 2
    Helpful Answer Positive Rating
hakeen said:
the answer is w=10000*sqrt(230).
Click to expand...
How did you work that out?:???:
(I agree with the answer)

- - - Updated - - -

Baas Rietrot said:
This looks like the start of a phase margin calculation.
Click to expand...
Oh, right - for poles at 10KHz, 100KHz and 200KHz.
I'd just use a simulator (or spreadsheet), but I'd still be interested to hear how Hakeen did the calculation.
 

I would also want to know how hakeen did it, this might help to eliminate the tedious trail and error method.

Please post master hakeen:smile:
 

Hello hakeen
it is completely right.
could you write the answer completely ? how did you find it ? it has a formula to solve these equation ?

- - - Updated - - -

By trial and error, w = about 154000
I have no idea how to calculate it. What's this for?
Click to expand...
i want to calculate an amplifier G.M(Gain Margin) and P.M(Phase margin)
 

Hello

thanks for good posts, but I am not math-master.
Anyway, for solution two important things

1)arctan x + arctan y = arctan ( (x+y)/(1-x*y))
2)arctan(x) = -pi --> x=0

so think it is x=w/10^4 then

[arctan(x)+arctan(x/10)]+arctan(x/20) = -pi

so from 1&2

x= sqrt(230) and w= sqrt(230)*10^4

Hope helps.

Cheers
 
If you apply tan on both sides first

tan( arctan(w/10^4) + arctan(w/10^5) +arctan(w/2*10^5) ) = 0

then simple use tan ( A + B +C ) = tanA*tanB*tanC/(1-(tanA*tanB)-(tanA*tanB*tanC)) formula

Immediately you see that w = 0 is a solution or you get a cubic at the bottom

w^3/(10^4*10^5*2*10^5)/(1-(w^2/10^4*10^5)-w^3/(10^4*10^5*2*10^5)

hope it helps
K
 
  • Like
Reactions: baby_1

    B

    baby_1

    Points: 2
    Helpful Answer Positive Rating
Status
Not open for further replies.

Similar threads

Part and Inventory Search

Welcome to EDABoard.com

Sponsor

Back
Top