Edge Detection - Revision history

FoxFireFive at 22:09, 14 March 2026

2026-03-14T22:09:34Z

← Older revision		Revision as of 22:09, 14 March 2026
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	~~'''~~Edge detection~~'''~~ is the process of ~~sending~~ a signal ~~at the moment a signal transitions~~.		Edge detection is the process of detecting when a signal changes state. There are three types of edge detection:

	A '''~~rising edge~~''' ~~refers to the instant~~ when a signal ~~changes~~ from ~~''off''~~ to ~~''on''~~.		'''Rising Edge''': when a signal goes from OFF to ON.

	A '''~~falling edge~~''' ~~refers to the instant~~ when a signal ~~changes~~ from ''on'' ~~to ''off~~''.		'''Falling Edge''': when a signal goes from ON to OFF.

			'''Either Edge''': when a signal goes from either OFF or ON.

	== Construction ==		== Construction ==
	[[File:Raising-edge-detector.png\|thumb\|right\|alt=Raising edge detector\|Raising edge detector]]		[[File:Raising-edge-detector.png\|thumb\|right\|alt=Raising edge detector\|Raising edge detector]]
	You can detect a rising edge by checking whether the input signal was ''off'' some number of [[Tick\|ticks]] ago but is now ''on''.		[[File:edge-oscillator.png\|alt=oscilloscope\|Raising Edge on oscilloscope \|thumb]]You can detect a rising edge by checking whether the input signal was ''off'' some number of [[Tick\|ticks]] ago but is now ''on''.

	This can be done using an [[AND Gate]] and an [[Inverter]].		This can be done using an [[AND Gate]] and an [[Inverter]]. Connect one input of the AND gate directly to your signal, and connect the other input through the inverter.
	Connect one input of the AND gate directly to your signal, and connect the other input through the inverter.

	When the input signal turns on, the direct input to the AND gate is immediately on. The inverter output, however, is delayed by 1 tick, so it remains ''on'' for one more tick.		When the input signal turns on, the direct input to the AND gate is immediately on. The inverter output, however, is delayed by 1 tick, so it remains ''on'' for one more tick.
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	On the next tick, the AND gate turns ''on'' while the inverter output turns ''off''. At this point, not all AND gate inputs are ''on'', so it will be marked to turn ''off'' on the following tick.		On the next tick, the AND gate turns ''on'' while the inverter output turns ''off''. At this point, not all AND gate inputs are ''on'', so it will be marked to turn ''off'' on the following tick.

	The pulse length is determined by the delay between the direct and inverted inputs of the AND gate.		The pulse length is determined by the delay between the direct and inverted inputs of the AND gate. You can extend the pulse to 2 ticks using a [[Buffer]], or make it 2 ticks or longer with a [[Delayer]].
	You can extend the pulse to 2 ticks using a [[Buffer]], or make it 2 ticks or longer with a [[Delayer]].

	== Example Signal Diagram ==		== Example Signal Diagram ==
	Below is an example timing diagram showing how a rising edge detector behaves:		Below is an example timing diagram showing how a rising edge detector behaves:{{Binary signal
	* '''Input''' shows the original signal toggling between off and on.
	* '''Output''' is the short pulse generated on each rising edge of the input signal.

	{{Binary signal
	\| signals=Input, Output		\| signals=Input, Output
	\| signal1=000011110000111		\| signal1=000011110000111
	\| signal2=000010000000100		\| signal2=000010000000100
	}}{{Note\|NOTE: This diagram is simplified for educational purposes. While this diagram suggests that the output turns on immediately when the input turns on, in reality, logic gates create a delay, and the output signal will lag behind the input signal by at least one tick.}}		}}{{Note\|NOTE: This diagram is simplified for educational purposes. While this diagram suggests that the output turns on immediately when the input turns on, in reality, logic gates create a delay, and the output signal will lag behind the input signal by at least one tick.}}

	~~How it looks in the Logic World:~~
	~~[[File:edge-oscillator.png\|frame\|center\|alt=oscilloscope\|Raising Edge on oscilloscope ]]~~

GHXX: Tweak wording a bit

2025-10-17T17:01:16Z

Tweak wording a bit

← Older revision		Revision as of 17:01, 17 October 2025
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	\| signal1=000011110000111		\| signal1=000011110000111
	\| signal2=000010000000100		\| signal2=000010000000100
	}}{{Note\|NOTE: This diagram is simplified for ~~education~~ purposes. While this diagram suggests that the output turns on immediately when the input turns on, in reality, logic gates create a delay, and the output signal will lag the input signal by at least one tick.}}		}}{{Note\|NOTE: This diagram is simplified for educational purposes. While this diagram suggests that the output turns on immediately when the input turns on, in reality, logic gates create a delay, and the output signal will lag behind the input signal by at least one tick.}}

	How it looks in the Logic World:		How it looks in the Logic World:
	[[File:edge-oscillator.png\|frame\|center\|alt=oscilloscope\|Raising Edge on oscilloscope ]]		[[File:edge-oscillator.png\|frame\|center\|alt=oscilloscope\|Raising Edge on oscilloscope ]]

N00basaurus: Added a note below the example signal diagram explaining the lack of a delay on the output.

2025-10-12T03:14:34Z

Added a note below the example signal diagram explaining the lack of a delay on the output.

← Older revision		Revision as of 03:14, 12 October 2025
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	\| signal1=000011110000111		\| signal1=000011110000111
	\| signal2=000010000000100		\| signal2=000010000000100
	}}		}}{{Note\|NOTE: This diagram is simplified for education purposes. While this diagram suggests that the output turns on immediately when the input turns on, in reality, logic gates create a delay, and the output signal will lag the input signal by at least one tick.}}

	How it looks in the Logic World:		How it looks in the Logic World:
	[[File:edge-oscillator.png\|frame\|center\|alt=oscilloscope\|Raising Edge on oscilloscope ]]		[[File:edge-oscillator.png\|frame\|center\|alt=oscilloscope\|Raising Edge on oscilloscope ]]

DjSapsan: /* Circuit Implementation */

2025-10-07T18:03:09Z

Circuit Implementation

← Older revision		Revision as of 18:03, 7 October 2025
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	A '''falling edge''' refers to the instant when a signal changes from ''on'' to ''off''.		A '''falling edge''' refers to the instant when a signal changes from ''on'' to ''off''.

	== ~~Circuit Implementation~~ ==		== Construction ==
	[[File:Raising-edge-detector.png\|thumb\|right\|alt=Raising edge detector\|Raising edge detector]]		[[File:Raising-edge-detector.png\|thumb\|right\|alt=Raising edge detector\|Raising edge detector]]
	You can detect a rising edge by checking whether the input signal was ''off'' some number of [[Tick\|ticks]] ago but is now ''on''.		You can detect a rising edge by checking whether the input signal was ''off'' some number of [[Tick\|ticks]] ago but is now ''on''.

DjSapsan: improved formatting and did todo

2025-10-07T18:02:13Z

improved formatting and did todo

← Older revision		Revision as of 18:02, 7 October 2025
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	Edge detection is the ~~action~~ of sending a signal at the ~~edge of~~ a ~~signals transition~~.		'''Edge detection''' is the process of sending a signal at the moment a signal transitions.

	~~Rising~~ edge refers to the ~~instance in time~~ when a signal ''~~rises~~'' ~~from off~~ to on.		A '''rising edge''' refers to the instant when a signal changes from ''off'' to ''on''.

	~~Falling~~ edge refers to the ~~instance in time~~ when a signal ''~~falls~~'' ~~from on~~ to off.		A '''falling edge''' refers to the instant when a signal changes from ''on'' to ''off''.

	== Circuit Implementation ==		== Circuit Implementation ==
	~~{{Todo~~\|~~Add pictures}}~~		[[File:Raising-edge-detector.png\|thumb\|right\|alt=Raising edge detector\|Raising edge detector]]
	You can detect a rising edge by ~~looking for an instance in time when~~ the input signal was off some number of [[Tick\|ticks]] ago, but is now on.		You can detect a rising edge by checking whether the input signal was ''off'' some number of [[Tick\|ticks]] ago but is now ''on''.

	~~You~~ can ~~do this with~~ an [[AND Gate]] and an [[Inverter]].		This can be done using an [[AND Gate]] and an [[Inverter]].
			Connect one input of the AND gate directly to your signal, and connect the other input through the inverter.

	~~Connecting one input of~~ the ~~AND gate to your~~ input signal, ~~and another~~ input to ~~your input signal through an~~ inverter.		When the input signal turns on, the direct input to the AND gate is immediately on. The inverter output, however, is delayed by 1 tick, so it remains ''on'' for one more tick.
			Since both inputs of the AND gate are ''on'', it becomes marked for activation in the next tick.

	~~When you turn~~ the ~~input signal on~~, the AND ~~gates input will turn~~ on ~~instantly. Since~~ the inverter ~~has a 1 tick delay before its~~ output ~~is updated~~, ~~its output is still~~ on, ~~and~~ so ~~is the other input of the AND gate, marking the AND gate~~ to ~~be updated in~~ the ~~next~~ tick.		On the next tick, the AND gate turns ''on'' while the inverter output turns ''off''. At this point, not all AND gate inputs are ''on'', so it will be marked to turn ''off'' on the following tick.

	On the ~~next tick,~~ the ~~AND gate turns on,~~ and ~~the inverter turns off. The AND gates~~ inputs ~~are no longer all on, and~~ the AND gate ~~is marked~~ to ~~be turned off in the next tick~~.		The pulse length is determined by the delay between the direct and inverted inputs of the AND gate.
			You can extend the pulse to 2 ticks using a [[Buffer]], or make it 2 ticks or longer with a [[Delayer]].

	~~The length of this pulse~~ is ~~determined by~~ the ~~delay~~ between ~~the input signal~~ and the ~~inverted input~~ of the ~~AND gate~~. ~~You can make the pulse length 2 ticks long by introducing a [[Buffer]]~~, ~~or you can make~~ it ~~2 ticks or more using a~~ [[~~Delayer~~]].		== Example Signal Diagram ==
	~~{{Todo\|Add timing diagram}}~~		Below is an example timing diagram showing how a rising edge detector behaves:
			* '''Input''' shows the original signal toggling between off and on.
			* '''Output''' is the short pulse generated on each rising edge of the input signal.

			{{Binary signal
			\| signals=Input, Output
			\| signal1=000011110000111
			\| signal2=000010000000100
			}}

			How it looks in the Logic World:
			[[File:edge-oscillator.png\|frame\|center\|alt=oscilloscope\|Raising Edge on oscilloscope ]]

N00basaurus: Added Edge Detection page

2025-10-06T05:59:51Z

Added Edge Detection page

New page

Edge detection is the action of sending a signal at the edge of a signals transition.

Rising edge refers to the instance in time when a signal ''rises'' from off to on.

Falling edge refers to the instance in time when a signal ''falls'' from on to off.

== Circuit Implementation ==
{{Todo|Add pictures}}
You can detect a rising edge by looking for an instance in time when the input signal was off some number of [[Tick|ticks]] ago, but is now on.

You can do this with an [[AND Gate]] and an [[Inverter]].

Connecting one input of the AND gate to your input signal, and another input to your input signal through an inverter.

When you turn the input signal on, the AND gates input will turn on instantly. Since the inverter has a 1 tick delay before its output is updated, its output is still on, and so is the other input of the AND gate, marking the AND gate to be updated in the next tick.

On the next tick, the AND gate turns on, and the inverter turns off. The AND gates inputs are no longer all on, and the AND gate is marked to be turned off in the next tick.

The length of this pulse is determined by the delay between the input signal and the inverted input of the AND gate. You can make the pulse length 2 ticks long by introducing a [[Buffer]], or you can make it 2 ticks or more using a [[Delayer]].
{{Todo|Add timing diagram}}