Before revision: Digital RTAs use digital sampling technology and microprocessor based digital signal processing to perform necessary calculations, such as fast Fourier transforms, to perform the measurements and thus do not need analog hardware filters to isolate each frequency band.
After revision: Digital RTAs use digital sampling technology and microprocessor-based digital signal processing to perform necessary calculations, such as fast Fourier transforms, to perform the measurements and thus do not need analog hardware filters to isolate each frequency band.