About phase and amplitude after filtering

[Coq_Rouge]

Go to help in the toolbar then select Find Examples. Do a search for iir and locate the "IIR Filtering and Response.vi" That will show you that filters are not total pass-through or total block. Hope this will help you some

[P@Anand]

Where will change your amplitude , freq. if the freq. is changing track the change and give that value to the filter's cutoff freq. put your effort and try your best.

[rpursley8]

In your vi you added two signals to your original one.  A 50 Hz sinusoid and some white noise.  Both signals are completely different in the frequency domain and have to be addressed separately.  You should first have a bandstop filter centered at 50 Hz to filter out this signal.  It should be narrowband (maybe 48 Hz to 52 Hz, and medium order, 6th should work).  This will filter out that signal.  That also means that your original signal cannot be in that same band, it will be filtered as well.  Next you should have a bandpass filter centered at the same frequency as your original signal.  If your original signal is really going to be a sinusoid, you can make this filter fairly narrowband as well.  Any bandpass filter you choose will have some effect on the amplitude and phase of your signal.  There is no way to avoid this.  Fortunately, at each frequency, the effect is fixed so it can accounted for.