Group characters: Sequences with good correlation properties

The structure of the group of integers relatively prime to n under multiplication modulo n is reviewed, and the basic properties of characters defined on that group is developed. Appropriately chosen subcollections of the characters when viewed as periodic sequences are then shown to have relatively ideal autocorrelation and cross correlation properties. The results of a computer study indicate that the same subcollections when viewed as finite length sequences also have very good aperiodic autocorrelation and cross correlation properties.