jrive

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These are replies submitted by jrive

@acer  -- perfect, thank you!!!

@acer thank you.

There's something I don't get...I have three unknowns (assuming C1=C2), so not sure why I can't use the inequality.  I occurs to me I could instead use C1=C2 in the system of equations (restricting the gain to 1)  - maybe that'll work. 

I still need to look at this further, though.   The solution for  R1 results in an imaginary value which shouldn't be the case....

 

Thank you for your help!

@acer what you're seeing are typos when I entered the data on here, since I could not cut and paste it directly from my Maple doc.

Currently, I get this error and have not been able to resolve it, no matter what I try:

sys := {`&omega;res` = 0.1635*10^8*2*Pi, simplify(z3res) = 9 + 0.000150*I, 1 <= abs(vores/vin)}

sol2 := solve(sys, {C1, C2, L1, R1})

Warning, solve may be ignoring assumptions on the input variables.
Error, (in unknown) invalid input: SolveTools:-Inequality expects its 1st argument, eqns, to be of type ({list, set})({`<`, `<=`, `=`}), but received [C2 < 0, And(-(-1+signum(0, C1+C2, 1))*Pi <= Pi, -Pi < -(-1+signum(0, C1+C2, 1))*Pi)]

(I can't figure out how to copy Maple input onto here --the formatting gets all messed up.)  Please see attached file.

Thanks for any pointers!  filter.mw

restart

assume(vin, real)

assume(C1, real)

assume(C2, real)

assume(L1, real)

assume(R1, real)

assume(omega, real)

assume(vin, real)

z1 := R1/((I*omega*C1)*(R1+1/(I*omega*C1)))

-I*R1/(omega*C1*(R1-I/(omega*C1)))

(1)

simplify(-I*R1/(omega*C1*(R1-I/(omega*C1))), 'size')

I*R1/(-R1*omega*C1+I)

(2)

 

 

z2 := z1+I*omega*L1

-I*R1/(omega*C1*(R1-I/(omega*C1)))+I*omega*L1

(3)

z3 := z2/((I*omega*C2)*(z2+1/(I*omega*C2)))

-I*(-I*R1/(omega*C1*(R1-I/(omega*C1)))+I*omega*L1)/(omega*C2*(-I*R1/(omega*C1*(R1-I/(omega*C1)))+I*omega*L1-I/(omega*C2)))

(4)

simplify(-I*(-I*R1/(omega*C1*(R1-I/(omega*C1)))+I*omega*L1)/(omega*C2*(-I*R1/(omega*C1*(R1-I/(omega*C1)))+I*omega*L1-I/(omega*C2))))

(I*C1*L1*R1*omega^2+omega*L1-I*R1)/(-I-C1*C2*L1*R1*omega^3+I*C2*L1*omega^2+R1*(C1+C2)*omega)

(5)

 

voc := vin/((I*omega*C1)*(R1+1/(I*omega*C1)))

-I*vin/(omega*C1*(R1-I/(omega*C1)))

(6)

simplify(-I*vin/(omega*C1*(R1-I/(omega*C1))))

I*vin/(-R1*omega*C1+I)

(7)

zthev := simplify(z1)

I*R1/(-R1*omega*C1+I)

(8)

vounloaded := voc/((I*omega*C2)*(zthev+I*omega*L1+1/(I*omega*C2)))

-vin/(omega^2*C1*(R1-I/(omega*C1))*C2*(I*R1/(-R1*omega*C1+I)+I*omega*L1-I/(omega*C2)))

(9)

simplify(-vin/(omega^2*C1*(R1-I/(omega*C1))*C2*(I*R1/(-R1*omega*C1+I)+I*omega*L1-I/(omega*C2))))

-I*vin/(-I-C1*C2*L1*R1*omega^3+I*C2*L1*omega^2+R1*(C1+C2)*omega)

(10)

simplify(-vin/(omega^2*C1*(R1-I/(omega*C1))*C2*(I*R1/(-R1*omega*C1+I)+I*omega*L1-I/(omega*C2))))

-I*vin/(-I-C1*C2*L1*R1*omega^3+I*C2*L1*omega^2+R1*(C1+C2)*omega)

(11)

 

 

sol1 := solve(Im(vounloaded) = 0, omega)

Warning, solve may be ignoring assumptions on the input variables.

 

0, (C1*C2*L1*(C1+C2))^(1/2)/(C1*C2*L1), -(C1*C2*L1*(C1+C2))^(1/2)/(C1*C2*L1)

(12)

`&omega;res` := sol1[2]

(C1*C2*L1*(C1+C2))^(1/2)/(C1*C2*L1)

(13)

vounloaded

-vin/(omega^2*C1*(R1-I/(omega*C1))*C2*(I*R1/(-R1*omega*C1+I)+I*omega*L1-I/(omega*C2)))

(14)

vores := simplify(subs(omega = `&omega;res`, vounloaded))

-C1*vin/C2

(15)

``

NULL

z3res := simplify(subs(omega = `&omega;res`, z3))

(C1^2*R1-I*(C1*C2*L1*(C1+C2))^(1/2))/C2^2

(16)

simplify((C1^2*R1-I*(C1*C2*L1*(C1+C2))^(1/2))/C2^2)

(C1^2*R1-I*(C1*C2*L1*(C1+C2))^(1/2))/C2^2

(17)

 

sys := {abs(vores/vin) >= 1, `&omega;res` = (0.1356e8*2)*Pi, simplify(z3res) = 9+I*0.150e-3}

{(C1^2*R1-I*(C1*C2*L1*(C1+C2))^(1/2))/C2^2 = 9.+0.150e-3*I, (C1*C2*L1*(C1+C2))^(1/2)/(C1*C2*L1) = 85199992.78, 1 <= abs(C1/C2)}

(18)

``

sol2 := solve(sys, {C1, C2, L1, R1})

Warning, solve may be ignoring assumptions on the input variables.

 

Error, (in unknown) invalid input: SolveTools:-Inequality expects its 1st argument, eqns, to be of type ({list, set})({`<`, `<=`, `=`}), but received [C2 < 0, And(-(-1+signum(0, C1+C2, 1))*Pi <= Pi, -Pi < -(-1+signum(0, C1+C2, 1))*Pi)]

 

sol := sol2[3]

sol2[3]

(19)

R1sol := sol2[4]

sol2[4]

(20)

C1sol := sol2[1]

sol2[1]

(21)

``

Solution

subs(C2 = 0.10e-10, L1sol)

sol2[3]

(22)

subs(C2 = 0.10e-10, R1sol)

sol2[4]

(23)

``

 

@Kitonum thank you.  What did you change to get it to solve for you?  I never was able to get the solution you got; is it because you entered the formulas into sys, as opposed to the variables to which they were assigned?  (eg. you entered 1<=abs(C1/C2, instead of abs(vores/vin)>=1? 

Thanks again

 

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