I am trying to learn FPGA programming, and I would like to analyze an audio input.
I would like to know what kind of frequencies are present in the signal but without using Fourier transform - there are two reasons for this.
First one is I dont need to know the exact frequency of the incoming signal, and the second reason is simple - I have just started learning FPGA and Fourier transform is beyond my skill level to implement.
So, are there any methods of checking if a signal of given frequency is part of the audio input? Say, I would like to know if any signal in frequency range 3KHz-5KHz is present in the input. How can such a problem be approached?
Edit. My first thought was to use a pair of low and high pass filters to do the job, but I am not sure if this would work well, because they only pass through the current signal.