Digital signal processing
The main difference between the two types is that the analog RTAs use a series of hardwired, analog bandpass filters to break the signal into frequency bands prior to measuring it. 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. The digital approach to signal analysis generally yields much higher accuracy and resolution and thus most RTAs currently in production use digital signal processing technology. Digital signal processing is more cost effective.