Pingy
2008-12-09, 15:55
How can I calculate the 3db Frequency for a given filter?
I have a plot of the voltage vs. frequency from 100Hz to 100MHz.
I know the formula for gain is:
G(db) = 20* log(Vo/Vi) where Vo is Vout and Vi is Vin.
I know that the frequency of the carrier wave is: c(t) = C*sin(wt + k) where C is the amplitude, w is the angular frequency and k is a phase constant.
My input ac sine wave has an amplitude of 1 V and a DC Offset of 0.
I know the message wave is of the form: m(t) = M*cos(wt + k) where M is the amplitude...etc
The wave sent over the air is of the form: S(t) = [1+m(t)]*c(t)
The 3db frequency is when the Vo = 1/sqrt(2) * Vin. But how to I get frequency from this calculation?
So confused. The project is due tomorrow night and I put off this part until right now. I thought it would be intuitive but its really confusing.
Help???
I have a plot of the voltage vs. frequency from 100Hz to 100MHz.
I know the formula for gain is:
G(db) = 20* log(Vo/Vi) where Vo is Vout and Vi is Vin.
I know that the frequency of the carrier wave is: c(t) = C*sin(wt + k) where C is the amplitude, w is the angular frequency and k is a phase constant.
My input ac sine wave has an amplitude of 1 V and a DC Offset of 0.
I know the message wave is of the form: m(t) = M*cos(wt + k) where M is the amplitude...etc
The wave sent over the air is of the form: S(t) = [1+m(t)]*c(t)
The 3db frequency is when the Vo = 1/sqrt(2) * Vin. But how to I get frequency from this calculation?
So confused. The project is due tomorrow night and I put off this part until right now. I thought it would be intuitive but its really confusing.
Help???