A digital signal with fs = 8kHz includes 1kHz, 1.5kHz and 2kHz sin waves, and an AWGN. Design a filter to attenuate the 1.5kHz sin wave and as much as possible the AWGN by 50dB but keep the 1kHz and 2kHz sin waves

a) Design the filter with the summation of standard FIR filters b) Design the filter with the cascade of the standard FIR filters

The code that I have is following:

fs = 8000;

fm = 1000; fm1 = 1500; fm2 = 2000;

t = 0: 1/fs :4 ; t1 = [zeros(1,fs) 0: 1/fs :3]; t2 = [zeros(1,2*fs) 0: 1/fs :2];

si = sin(2*pi*fm*t); si1 = sin(2*pi*fm1*t1); si2 = sin(2*pi*fm2*t2);

x = si +si1 +si2;

soundsc (x,fs);

noi = rand (1, length(t)) ;

sinoi = x + noi ;

soundsc (sinoi,fs);

I'm stuck now how to continue. Someone can help me, please?