For our project, we used an eighth order inverse Chebyshev filter to filter the input signal. We forced the input signal to have a range of frequencies from 1kHz to 30kHz. The lowpass filter design was to filter out frequencies higher than ~18kHz. Professional studios use better equipment and achieve better performance up to 20kHz. An inverse Chebyshev filter is used because it has a maximally flat frequency response in the pass-band and an equal rippled frequency response in the stop-band. A conventional Chebyshev filter has the reverse effect. It requires the same order as a Chebyshev filter to implement the same frequency response band, but more elements to implement. WE don't care about the expense of the filter used for recording, though, since a recording studio will use the investment for an optimal output. The formula for an inverse Chebyshev filter's frequency response magnitude is given in Formula 3.
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After passing through the input filter, the signal will have all of its frequency components above the cutoff frequency minimized by the filter, so the signal can be recorded without nasty aliasing problems. The aliasing problems will return, so let's define this concept more thoroughly.