# Pulse (electrical engineering)

In electrical engineering, the term pulse refers to a periodically repeating impulse-like or shock-like event. It is synonymous with the term pulse train .

## Determinations

Examples of pulse shapes
Above: Unipolar square pulse ; left ideal - right real
Bottom left: bipolar pulse (alternating pulse)
Bottom right: oscillation pulse or pulse burst

While a pulse is a one-off process whose instantaneous values ​​only deviate noticeably from zero within a limited period of time, a pulse in electrical engineering is defined as a periodic process consisting of a continuously repeating sequence of identical pulses. The term momentum in this context should not be confused with the concept of momentum from the field of mechanics .

A pulse can be characterized by its period or by a pulse frequency ( pulse repetition frequency ) , and also by the height and duration of the pulses. The pulse shape can be included in the naming of the pulse, e.g. B. square pulse, sawtooth pulse. ${\ displaystyle T}$${\ displaystyle f = 1 / T}$

A pulse can be represented spectrally by superimposing a discrete series of harmonic oscillations. For an impulse you need a continuous superposition of harmonic oscillations. A single pulse thus has a continuous spectrum, while a periodic pulse sequence has a discrete line spectrum.

In the English-language literature, no distinction is usually made between the terms pulse and pulse . In German technical jargon too, “pulse” often means an impulse.

## Applications

### Square pulse for modulation

With a square pulse, the two states appear like logic levels , which can be designated with `0`and `1`. However, they do not represent digits of a number and contain no information like a digital signal . However, information can be contained in the duty cycle due to the continuously adjustable width of the pulses or their frequency. By means of the pulse duration modulation and the pulse frequency modulation , an analog signal is transmitted with as little interference as a digital signal with steep edges because the pulse width and frequency can hardly be falsified. At the end of the transmission path, the information can easily be digitized by measuring the width (time) or the frequency using counting methods, see digital measurement technology .

### Square pulse for synchronization

In digital technology, many processes do not run according to runtime, but rather synchronously with a clock signal . In microprocessor technology, a clock generator always controls the work flow of the processor, and this controls (depending on the make with an additional pulse) the parallel data transmission from or to memory and peripherals.

## supporting documents

1. DIN 5483-1: 1983-06 “Time-dependent quantities”, No. 5.4
2. DIN IEC 60469-1: 1991-05 "Impulse technology - impulse terms and definitions", No. 5.4.1
3. DIN 5483-1 No. 5; DIN IEC 60469-1, no. 2.2.2
4. DIN 5483-1, No. 6; DIN IEC 60469-1, No. 5.3.1
5. ^ Karl Küpfmüller: Theoretical electrical engineering and electronics , 14th edition 1993, Springer Verlag, ISBN 3-540-56500-0