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? he'd buy me a fairing should please me, And then for a kiss, oh! he vowed he would tease me, He promised he'd bring me a bunch of blue ribbons, To tie up my bonny brown hair. </poem> Cohen's "Folk Music" gives a different version of the lyrics: <poem> O dear, what can the matter be? O dear, what can the matter be? O dear, what can the matter be? Johnny's so long at the fair. He promised he'd bring me a bunch of blue ribbons. He promised he'd bring me a bunch of blue ribbons. He promised he'd bring