Impulse technique

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The pulse technique as a branch of electrical engineering is concerned with the production, shaping, transmission and processing of current and voltage pulses . It is a specialty of electronics and can be seen as a “link” between analog technology and digital technology .

Historical

With the emerging technology of electron tubes, the first pulse technology applications arose. These were z. B. the (multistable) flip-flops and their use in meters .

Impulse technology reached its peak with radar and television technology. As was also soon in all fields of electronics electron tube by the transistor displaced.

Classic impulse technology is currently being replaced by its modern form, digital technology, in many areas of application. The methods of pulse technology are limited to the implementation of the special digital building stages, such as logic gates , analog-digital converters , digital-analog converters , pulse regeneration and pulse transmission.

Impulses

Terms

In electrical engineering, a pulse is understood to be a single, time-limited surge-like current, voltage or power curve. A periodically repeating pulse train, however, is called a pulse .

Impulses are roughly classified according to their shape. One speaks of a square pulse , needle pulse , triangular pulse, bell pulse , wave packet , etc.

Parameters

The ideal square pulse is not possible; its shape is distorted as it is generated and transmitted . In practice, it has a finite edge steepness (characterized by the rise and fall time ) and often shows an overshoot . In the case of the pulse, the pulse repetition frequency and the duty cycle are added as the main parameters . Fluctuations in the pulse intervals are called jitter .

Mathematical treatment

Since the active elements of impulse technology are essentially non-linear, there is also no closed mathematical method for treating them. When using (mostly passive) linear components, however, the theories of the Fourier series , the Fourier transformation and the Laplace transformation can be used. The theory of scanning systems is also useful for impulse technology.

The propagation of impulses along electrical lines and the reflections that occur at the cable ends can be described with the methods of line theory , in simple cases with the help of an impulse timetable or the Bergeron method .

Components

On the one hand, the pulse technology places very high demands on the components , because the shape of the pulses should be falsified as little as possible. On the other hand, the non-linear properties of the active components are consciously used for the generation and shaping of pulses. Many passive and active components commonly used in analog electronics are used in pulse technology with a different or extended functionality:

Construction stages

Pulse generators are used to generate pulses and pulses with the properties required for the respective application. According to the very different functional principles for generation, one differentiates, for example:

Often they are also classified according to the pulse shape generated:

Construction stages for pulse shaping is given to using, the shape change of pulses or restore:

  • Limiters cut the signal level and are used, for example, to turn sinusoidal signals into rectangular ones.
  • Clamping circuits are necessary to restore a "lost" DC voltage component (for example during a transmission).
  • Threshold switches ( Schmitt trigger ) transform constantly changing signals into square -wave signals.
  • The Miller integrator is used to generate linearly rising and / or falling pulses.

Pulse amplifiers work according to two essentially different principles:

  • Linear amplifiers amplify a pulse without distorting its shape. It must therefore be broadband amplifiers.
  • Switching amplifiers use their essential non-linearities ( e.g. saturation ) to reshape the pulses or to regenerate their shape.

Often pulses are interleaved and have to be separated again at the receiver with the help of an assembly for pulse separation. Integrating and differentiating elements in combination with threshold switches are usually used for this purpose .

Pulse measurement technology

Pulse generators allow the provision (synthesis) of arbitrarily shaped pulses for the control of pulse technology systems. The most important measuring device for the analysis of pulse trains is the oscilloscope , for single pulses the storage oscilloscope . Peak voltmeters, pulse power meters and frequency meters are used to determine the pulse parameters .

In addition, impulse technology provides special measuring methods for other technical sciences . Typical examples are pulse counters , pulse reflectometers , echo sounders and radar.

Practical pulse technology systems

literature

  • Rint, Curt : Handbook for high frequency and electrical engineers, Volume II . Publishing house for Radio-Foto-Kinotechnik GmbH, Berlin-Borsigwalde 1953.
  • Schröder, Heinrich / Feldmann, Gerhard / Rommel, Günther: Electrical communications engineering, III. Band . Publishing house for Radio-Foto-Kinotechnik GmbH, Berlin-Borsigwalde 1972.
  • Dobesch, Heinz: Impulse technology . Verlag Technik, Berlin 1964.
  • Lueg, Heinz : Basic systems, networks and circuits in pulse technology 1971.
  • Schildt, Gerhard-Helge: Impulse technology - basics and applications . Lyk-Informationstechnik, Brunn 2008, ISBN 978-3-9502518-1-4 .

Individual evidence

  1. ↑ DIN 5483-1: 1983-06 "Time-dependent quantities", No. 5
  2. ↑ DIN 5483-1, No. 6
  3. ^ Lyk technical book information