Matlab+ FIR filter that compensates for the ‘sinx/x’ effect

[cenation]

Can anyone help me with this?

I need to design a linear-phase FIR filter that compensates for the ‘sinx/x’ effect with a peak approximation error of -40 dB on the frequency band of
[0, 0.8π] radian.

 

[danielr]

It is not clear for me if the signal has a sinx/x shape in the time domain or in the frequency domain.

If you wish attenuate the side lobules with a low pass filter use

y is you signal in the time domain
fl=100; % LPF length
fbe=[0 0.1 0.2 1]; damps=[1 1 0 0 ]; % design of LPF parameters, analyze with 'doc firpm'
b=firpm(fl,fbe,damps); % create LPF impulse response
x3=2*filter(b,1,y); % LPF and scale downconverted signal

you will find abundant information in this practical book attached.

Regards, Daniel