About phase and amplitude after filtering

[khan;;;;;;;;;;;;;;;;]

Sir please give me solution to this

i have a signal with phase,frequency n amplitude. To this signal i have added noise and i filtered that signal

after filtering the amplitude and phase are reducing

how can i get exact values of phase and amplitude after filtering

if i change frequency, ampliteude or phase it should give exact results after filtering........

plz solve this one for me................

[P@Anand]

It depends on the order of the filter... Which filter you are using?... What is the order of that filter?.. If you are adding high frequency noise then you can use the 3rd order butterworth Lowpass filter.

[khan;;;;;;;;;;;;;;;;]

thanq for ur reply sir........

iam using filter express in that i have taken lowpass filter,cutoff freqency 50, topology butter tooth and order 6

but stil iam getting problem

[P@Anand]

What is the signal source that you are using and where you are adding the noise... Can you post the vi that you made?...

[khan;;;;;;;;;;;;;;;;]

k sir plz solve this for me and i will be very thankful to you.........

sir u just run this vi for different parameters but after filtering they should come exactly as per inputs........

[khan;;;;;;;;;;;;;;;;]

sir plz try this............

[leumaseoj]

hi, first leave the word sir. and dont put your word like this. in discussion forums it wont be good. you can use name or leave it. now if you use very higher order filters gain will automatically go low. so 6 order... check with your app. increase gain and reduce b/w and try it.

[khan;;;;;;;;;;;;;;;;]

thank you

i alredy used order 6 but iam not getting exact results

[P@Anand]

Hi upto my knowledge the mistake you made is the cut-off frequency.. your input signal is only 10Hz so you try setting it as the cutoff freq. Try this...

[khan;;;;;;;;;;;;;;;;]

k thanq u tried very well

but my problem is that if i change frequency, phase amplitude it should give exact results.......

in ur vi, it is working only to some fixed values of frequency and amplitude.....

if u got my prblem plz try

i wil waiting for ur reply........