While we understand intuitively that it is good to have as high a sampling frequency as possible compared to the frequency band of an input analog signal, hardware resource issues do not allow very high frequencies. The sampling theorem (If the highest frequency included in an input signal is fm(Hz), accurate analysis of the relevant frequency band requires that sampling should take place at a frequency of 2fm(Hz) or higher) is an index to what level of sampling frequency is suitable. If the sampling frequency is sampled at a frequency lower than 2fm(Hz), error may be generated in the analyzed spectrum. This error is termed aliasing (wrapping).