Example:-

Let us now also look at very special example, consider a disc rotating with a single radial line marked on the disc. The flashing strobe acts as a sampling system, since it illuminates the disc for extremely brief time intervals at a periodic rate. When the strobe frequency is much higher then the rotational speed of the disc, the speed of rotation of the disc is perceived correctly. When the strobe frequency becomes equal to the rotational frequency, the line appears to be at same position. When the strobe frequency becomes less than twice the rotational frequency, the rotation appears to be at a lower frequency than is actually the case. Furthermore due to phase reversal, the disc will appear rotating in the reverse direction .This phenomenon is known as stroboscopic effect.

Advantages of aliasing :

  Can be made to use ,i.e. carrier frequency for transmission & use Band Filter.

   We can use frequency of any multiple of

   Also in this case modulation by do not need pulses with average value zero.