At "pulsed" muon sources protons hitting the production target are bunched into short, intense and widely separated pulses, that provide a similar time structure in the secondary muon beam. An advantage of pulsed muon sources is that the event rate is only limited by detectors construction. Furthermore, detectors are active only after the incoming muon pulse, strongly reducing the accidental background counts. The virtual absence of background allows the extension of the time window for measurements up to about ten times the muon mean lifetime. The reverse of the medal is that the width of the muon pulse limits the time resolution.