Creating a BandPass Filter with Heaviside function

I've searched all over the internet for a simple code for a BandPass Filter and i've found nothing, then I started to think and may have figured an easy solution, so can someone check if it's right or not ?

In my project I have a step where I create an ideal bandpass filter and I have to filter a voice signal with that Bandpass filter

The filter code is as shown

N=411248;
 fs=48000;
 Fvec=linspace(-fs/2,fs/2,N);

 R1=heaviside(Fvec+3e3)-heaviside(Fvec+2e3);
 R2=heaviside(Fvec-2e3)-heaviside(Fvec-3e3);
 R=R1+R2;
 plot(Fvec,R)

where N is my audio length

fs is the sample rate of the audio

here i'm making it double sided, if you don't want to you can delete R2 wich is the negative side

in R1 I have the bandwidth to start from 2 kHz to 3 kHz , you're supposed to edit it to your desired frequencies.

I need someone to check it because its simplicity makes me worried that it can be wrong