high pass filter don't work

[lyn]

i used the following setting for the testing;

input signal 1: 2khz sinewave, amplitude 1V
input signal 2: 50Hz sinewave, amplitude 10V

the above 2 signals are added together and fed into a filter. my objective is to remove signal 1(1V sinewave). i've tried some filter but it don't seem to work. for the attached vi, i used high pass filter. the filter don't work.

i tried to view the frequency component of the signal before and after the filter and found out that both signals pass through the filter.

1. why isn't the 50Hz signal being filtered off?

i had the following values:

before filter after filter
50Hz ==> 3Hz
2kHz ==> 120Hz

the filter seem to scaled down the frequency compon
ent instead of filtering off the 50Hz.
2. why is this so, how can i solve this problem?
3. what should i take note when setting the parameters of the filter?

[DSPGuy]

You might try increasing the number of FIR filter taps. Also, would an IIR filter work for you? I recoded your example using the waveform filtering VIs that were developed for LabVIEW 6i. Please look at the number of taps for the FIR filter, and the PassBand and StopBand frequencies. Also, notice the IIR filter's superior suppression of the low frequency sinusoid.