Editing Delay-line memory (section)

== Electric delay lines ==
[[File:electricdelayline.jpg|thumb|Electric delay line (450&nbsp;ns), consisting of enamelled copper wire, wound around a metal tube]]

Electric delay lines are used for shorter delay times (nanoseconds to several microseconds). They consist of a long electric line or are made of discrete inductors and capacitors arranged in a chain. To shorten the total length of the line, it can be wound around a metal tube, getting some more capacitance against ground and also more inductance due to the wire windings, which are lying close together.

Other examples are:
* short coaxial or [[microstrip line]]s for phase matching in high-frequency circuits or [[Antenna (radio)|antenna]]s,
* hollow resonator lines in [[magnetron]]s and [[klystron]]s as helices in [[travelling-wave tube]]s to match the velocity of the electrons to the velocity of the [[electromagnetic waves]],
* [[undulator]]s in [[free-electron laser]]s.

Another way to create a delay time is to implement a delay line in an [[integrated circuit]] storage device. This can be done digitally or with a discrete-time analogue method. The analogue one uses charge transfer devices (either [[bucket-brigade device]]s or [[charge-coupled device]]s), which transport a stored electric charge stepwise from one end to the other.<ref>{{Cite web |title=RETICON: Product Summary: Discrete Time Analog Signal Processing Devices |url=https://www.synfo.nl/datasheets/Reticon.pdf |url-status=live |archive-url=https://web.archive.org/web/20221205113142/http://www.synfo.nl/datasheets/Reticon.pdf |archive-date=2022-12-05 |access-date=2023-09-07 |website=[[Reticon]]}}</ref> Both digital and analog methods are bandwidth limited at the upper end to the half of the clock frequency, which determines the steps of transportation.

In modern computers operating at gigahertz speeds, millimeter differences in the length of conductors in a parallel data bus can cause data-bit skew, which can lead to data corruption or reduced processing performance. This is remedied by making all conductor paths of similar length, delaying the arrival time for what would otherwise be shorter travel distances by using zig-zagging traces.