Pulse (signal processing)
Pulse shapes can arise out of a process called pulse-shaping. Optimum pulse shape depends on the application.
These can be found in pulse waves, square waves, boxcar functions, and rectangular functions. In digital signals the up and down transitions between high and low levels are called the rising edge and the falling edge. In digital systems the detection of these sides or action taken in response is termed edge-triggered, rising or falling depending on which side of rectangular pulse. A digital timing diagram is an example of a well-ordered collection of rectangular pulses.
A Nyquist pulse is one which meets the Nyquist ISI criterion and is important in data transmission. An example of a pulse which meets this condition is the sinc function. The sinc pulse is of some significance in signal-processing theory but cannot be produced by a real generator for reasons of causality.
In 2013, Nyquist pulses were produced in an effort to reduce the size of pulses in optical fibers, which enables them to be packed 10x more closely together, yielding a corresponding 10x increase in bandwidth. The pulses were more than 99 percent perfect and were produced using a simple laser and modulator.
g(t) = exp(-πt^2)
- Ángela Molina, Joaquín González, Pulse Voltammetry in Physical Electrochemistry and Electroanalysis, Springer, 2015 ISBN 3319212516.
- Joel Detrow. "Pointy pulses improve optical fiber throughput by a factor of 10". Gizmag.com. Retrieved 2013-12-06.
- Marcelo A. Soto; Mehdi Alem; Mohammad Amin Shoaie; Armand Vedadi; Camille-Sophie Brès; Luc Thévenaz; Thomas Schneider. "Optical sinc-shaped Nyquist pulses of exceptional quality : Nature Communications : Nature Publishing Group". Nature.com. Retrieved 2013-12-07.