## Trying to determine the output of a RC-filter with load

I have a low pass filter like this:

^{simulate this circuit – Schematic created using CircuitLab}

$V_{out}$ is measured right after $R_1$, which I suppose means that it is measured over the parallel part.

$R_2$ is the load of the filter. When this circuit is measured with an oscilloscope it seems like it is not dependent on the frequency at all. I would like to investigate why.

I tried to calculate the transfer function for the filter, but I am not sure that it is right.

$$ H(omega) = frac{1}{R_1(jomega C+frac{1}{R_2})+1}$$

I’m using $R_1 = 33text{k}Omega$, $R_2 = 1text{k}Omega$, and $C = 220$pF.

If I plot the frequency responce in Matlab with this, I just get a straight line going from the origin through `(1,.5), (2,1)`

where `(Hz, H(w))`

and so on.

Is this correct?