Nyquist frequency signal, whereas "Nyquist frequency" is a property of a discrete-time system. When the function domain is time, sample rates are usually expressed in samples per second, and the unit of Nyquist frequency is cycles per second (hertz). When the function domain is distance, as in an image sampling system, the sample rate might be dots per inch and the corresponding Nyquist frequency would be in cycles/inch. Referring again to Figure 1, undersampling of the sinusoid at 0.6 f is what allows there to be a lower-frequency "alias", which is a different function that produces the same set of samples. That
Oh Dear! What Can the Matter Be? we do think that we are sadly neglected; Because they don't visit the school. </poem> Oh Dear! What Can the Matter Be? "What Can the Matter Be?", also known as "Johnny's So Long at the Fair" is a traditional nursery rhyme that can be traced back as far as the 1770s in England. There are several variations on its lyrics. The "Oxford Dictionary of Nursery Rhymes" by Iona and Peter Opie traces this song back to an earlier folk ballad, recorded between 1770 and 1780, whose lyrics are: <poem> O what can the matter be And what can the matter