Author on pg 292 claims the windowed-sinc "is not a filter for signals with information encoded in time domain", because its "step response has overshoot and ringing". That phrase, along "encoded in frequency domain", are used in text, but I'm unsure they're ever explicitly defined. My guess:
- Frequency-domain encoded: periodic processes in a system - something that recurs, persists the duration of the signal, and is sensibly described by Fourier coefficients
- Time-domain encoded: the opposite - time-local events in a system, such as a sharp rise, temporary change in DC offset, momentary noise injection.
A single square pulse would qualify for latter, as the physical system that generated it almost certainly didn't synch hundreds of sinusoidal sources just right. A noiseless EEG would qualfiy for former, as neuronal excitations recorded as polarity alignments have periodic traits.
Is this accurate? If so, how is a filter's step response relevant in describing time-local events - and are there other "responses" characterizing time-encoded information?
Note: I'm aware of the step response's role in control systems, circuit design; I ask specifically about non-periodic "events" in a signal (if that's what time-encoded means).