Here are examples of three sounds that evoke pitch without being strictly periodic. A detailed discussion of these sounds can be found in the pitch chapter of the book.
Each of these sounds is approximately periodic, and their spectra have an approximately periodic structure, reminiscent of the strictly harmonic structure of periodic sounds. In each case, there is a clear period. If the sound is shifted by that period, it best resembles its unshifted version.
Harmonic complex with noise
Iterated repeated noise (IRN)