Signals in the time and frequency domain - Signals, Processes, and Systems - page 39

Illustration 34: Symmetrical rectangular pulse sequence with varying time reference point t = 0 s

In both representations it is the same signal. The lower one is staggered compared with the upper one by
T/2. Both representations have a different time reference point t = 0 s. A time displacement of T/2 is exactly
equivalent to a phase displacement of π . This explains the different phase spectra. On account of

τ /T = 1/2 all the even-numbered harmonics are lacking (i.e. the zero positions of the spectrum are 2 Hz,

4Hz etc).

All the large characteristic time values appear small in the
frequency domain, all the small characteristic time values
appear large in the frequency domain.

Example: Compare period length T and pulse duration τ