r i u co t ri r 9 iod 6 7 8 t nguG 2E Digital rcp ls ntariooof an rdog wrvcfoml siE tbrt ilustntcs the 6nitior achicvedwith l0 i r F ph3 Ali si t od r 5 z 9 t s n to3 sign lin 2 f A3urc 4 29 Elfcd of liasiry whcn siDusoidk s mplcd rt frlqueEy I 3l2lt E I i80 o f L S ttal lt qu ncy f2 trc r f a il h y tfpq fulElion fo r idcd rndog uritu Slr r ADC ri r s mpliog ntr EEE 102 Some Notes on the phenomenon of Aliasing 1 The Nyquist Sampling Theorem leads us to the conclusion that the following relationship must be satisfied in order to avoid aliasing an input signal frequency component fs 2f where fs is the sampling frequency and f is the highest significant frequency component in the signal being sampled 2 Conversely aliasing will occur if f fs 2 3 Alias frequencies can be calculated from the following equation f1 f2 mfs where f1 is the alias frequency f2 is the signal frequency and m 1 2 3 4 Possible alias frequencies are always less than half of the sampling frequency This must be so since if f1 fs 2 the Nyquist Sampling Theorem would have us conclude that such an alias could not be reproduced at that frequency