pulsed

Pulsed describes something that occurs in discrete bursts rather than continuously. In a pulsed signal or event, energy, light, or other quantity is emitted during short intervals called pulses, separated by periods of lower or zero activity. Each pulse has a duration, or pulse width, and the pulses may repeat at a specific rate called the repetition frequency. The proportion of time the signal is active is expressed as the duty cycle. Pulse shapes can vary; common forms include rectangular, Gaussian, or more complex waveforms.

In electronics and communications, pulsed signals are fundamental. They enable digital timing, data encoding, and precise measurements. Techniques such as pulse-width modulation control power delivery in electronics, while short laser or electrical pulses are used in timing circuits and diagnostic methods like time-domain reflectometry and radar.

In optics and photonics, pulsed light sources emit energy in brief bursts, with pulse durations spanning from femtoseconds to milliseconds. Ultrafast lasers produce extremely short pulses with high peak powers, enabling micromachining, nonlinear optics, and time-resolved spectroscopy. Repetition rate influences average power and imaging speed, for example in LIDAR systems.

In medicine and biology, pulsed energy is used for imaging and therapy. Pulsed ultrasound sends brief acoustic bursts for diagnostic imaging or focused therapeutic effects. Pulsed electrical stimulation can activate neural tissue in research and clinical settings. Pulsed fields are also used in processes such as sterilization and food preservation to minimize thermal damage.