Sinewave analysis in LPF

[EDIT: 20110808 10:29 CDT - reformat - WDR]

i have designed a LPF with the following spec.

%Low frequncy range BPF --------its actually a low pass filter with passband ripple=0.7db,stopband ripple=90db, passband=1000hz, stopband=1200hz.

My doubt is i have generated simulated sine wave with following spec.

fs = 20481; %sampling freq.
input_freq = 400;
t = 0:(1/fs):((1/fs)* (20481)); 
u = (0.7* sin(2*pi*input_freq*t));

whether i can give this simulated sinewave to my LPF design. If possible how to calculate the order of the filter and filter coefficient.

Here i am using firpmord() to calculate the order and firpm()for the fir.

Answer 1

[Honglei Chen]

Hi Venkatesh,

I don't quite understand your question. Since you already used firpmord and firpm, then you already have the order and filter coefficients. Then you can use filter() command to pass your signal through the filter.

HTH

Answer 2

[venkatesh P]

Whether i can use covolution? conv(input_Signal,Filter_coefficients)

Answer 3

[Honglei Chen]

You can do that too, since firpm gives an FIR filter.