OPEN-SOURCE SCRIPT
Updated [blackcat] L2 Ehlers Simple Decycler

Level: 2
Background
John F. Ehlers introuced Simple Decycler in Sep, 2015.
Function
In “Decyclers” in Sep, 2015, John Ehlers described a method for constructing an oscillator that could help traders detect trend reversals with almost no lag. Ehlers calls this new oscillator a decycler. The author began the process by isolating the high-frequency components present in the input data. He then subtracted these from the input data leaving only the lower-frequency components representing the trend. In more details, the idea is to subtract the high-pass filter value from the current close to get a “decycled” indicator that follows the trend rather well by removing much of the distracting high-frequency chatter. Apply a second high-pass filter using half the period from the first filter to the decycled indicator and you get a smoother result with much-reduced lag.
Key Signal
Decycle --> Ehlers Simple Decycler signal or center line of band
Pros and Cons
100% John F. Ehlers definition translation, even variable names are the same. This help readers who would like to use pine to read his book.
Remarks
The 84th script for Blackcat1402 John F. Ehlers Week publication.
Readme
In real life, I am a prolific inventor. I have successfully applied for more than 60 international and regional patents in the past 12 years. But in the past two years or so, I have tried to transfer my creativity to the development of trading strategies. Tradingview is the ideal platform for me. I am selecting and contributing some of the hundreds of scripts to publish in Tradingview community. Welcome everyone to interact with me to discuss these interesting pine scripts.
The scripts posted are categorized into 5 levels according to my efforts or manhours put into these works.
Level 1 : interesting script snippets or distinctive improvement from classic indicators or strategy. Level 1 scripts can usually appear in more complex indicators as a function module or element.
Level 2 : composite indicator/strategy. By selecting or combining several independent or dependent functions or sub indicators in proper way, the composite script exhibits a resonance phenomenon which can filter out noise or fake trading signal to enhance trading confidence level.
Level 3 : comprehensive indicator/strategy. They are simple trading systems based on my strategies. They are commonly containing several or all of entry signal, close signal, stop loss, take profit, re-entry, risk management, and position sizing techniques. Even some interesting fundamental and mass psychological aspects are incorporated.
Level 4 : script snippets or functions that do not disclose source code. Interesting element that can reveal market laws and work as raw material for indicators and strategies. If you find Level 1~2 scripts are helpful, Level 4 is a private version that took me far more efforts to develop.
Level 5 : indicator/strategy that do not disclose source code. private version of Level 3 script with my accumulated script processing skills or a large number of custom functions. I had a private function library built in past two years. Level 5 scripts use many of them to achieve private trading strategy.
Background
John F. Ehlers introuced Simple Decycler in Sep, 2015.
Function
In “Decyclers” in Sep, 2015, John Ehlers described a method for constructing an oscillator that could help traders detect trend reversals with almost no lag. Ehlers calls this new oscillator a decycler. The author began the process by isolating the high-frequency components present in the input data. He then subtracted these from the input data leaving only the lower-frequency components representing the trend. In more details, the idea is to subtract the high-pass filter value from the current close to get a “decycled” indicator that follows the trend rather well by removing much of the distracting high-frequency chatter. Apply a second high-pass filter using half the period from the first filter to the decycled indicator and you get a smoother result with much-reduced lag.
Key Signal
Decycle --> Ehlers Simple Decycler signal or center line of band
Pros and Cons
100% John F. Ehlers definition translation, even variable names are the same. This help readers who would like to use pine to read his book.
Remarks
The 84th script for Blackcat1402 John F. Ehlers Week publication.
Readme
In real life, I am a prolific inventor. I have successfully applied for more than 60 international and regional patents in the past 12 years. But in the past two years or so, I have tried to transfer my creativity to the development of trading strategies. Tradingview is the ideal platform for me. I am selecting and contributing some of the hundreds of scripts to publish in Tradingview community. Welcome everyone to interact with me to discuss these interesting pine scripts.
The scripts posted are categorized into 5 levels according to my efforts or manhours put into these works.
Level 1 : interesting script snippets or distinctive improvement from classic indicators or strategy. Level 1 scripts can usually appear in more complex indicators as a function module or element.
Level 2 : composite indicator/strategy. By selecting or combining several independent or dependent functions or sub indicators in proper way, the composite script exhibits a resonance phenomenon which can filter out noise or fake trading signal to enhance trading confidence level.
Level 3 : comprehensive indicator/strategy. They are simple trading systems based on my strategies. They are commonly containing several or all of entry signal, close signal, stop loss, take profit, re-entry, risk management, and position sizing techniques. Even some interesting fundamental and mass psychological aspects are incorporated.
Level 4 : script snippets or functions that do not disclose source code. Interesting element that can reveal market laws and work as raw material for indicators and strategies. If you find Level 1~2 scripts are helpful, Level 4 is a private version that took me far more efforts to develop.
Level 5 : indicator/strategy that do not disclose source code. private version of Level 3 script with my accumulated script processing skills or a large number of custom functions. I had a private function library built in past two years. Level 5 scripts use many of them to achieve private trading strategy.
Release Notes
b]OVERVIEWThe Ehlers Simple Decycler (ESD) indicator removes cyclical components from price data to reveal underlying trends, helping traders identify potential market movements and reversal points.
FEATURES
• Advanced cyclical filtering using Ehlers' methodology
• Dynamic upper and lower bands for trend confirmation
• Color-coded fill area for visual trend direction
• Built-in alert conditions for trading signals
• Customizable parameters for different market conditions
HOW TO USE
Select desired Price Source for analysis
Adjust High Pass Period to match market cycles
Monitor decycler line crossing between bands
Use color transitions to confirm trend direction
Set alerts for automated signal notifications
INTERPRETATION
• Decycler Line:
White line shows filtered price movement
Crossing above/below bands indicates potential reversals
• Bands:
Yellow band represents upper boundary
Fuchsia band marks lower boundary
Fill color changes with trend direction
ALERT CONDITIONS
• Upward Cross: Decycler crosses above previous value
• Downward Cross: Decycler crosses below previous value
PARAMETER GUIDELINES
• High Pass Period:
Lower values (20-50): Better for short-term trends
Higher values (50-100): Suitable for longer-term analysis
LIMITATIONS
• Performance varies with market volatility
• Best used alongside other technical indicators
• Results depend on proper parameter selection
Open-source script
In true TradingView spirit, the creator of this script has made it open-source, so that traders can review and verify its functionality. Kudos to the author! While you can use it for free, remember that republishing the code is subject to our House Rules.
For quick access on a chart, add this script to your favorites — learn more here.
Avoid losing contact!Don't miss out! The first and most important thing to do is to join my Discord chat now! Click here to start your adventure: discord.com/invite/ZTGpQJq 防止失联,请立即行动,加入本猫聊天群: discord.com/invite/ZTGpQJq
Disclaimer
The information and publications are not meant to be, and do not constitute, financial, investment, trading, or other types of advice or recommendations supplied or endorsed by TradingView. Read more in the Terms of Use.
Open-source script
In true TradingView spirit, the creator of this script has made it open-source, so that traders can review and verify its functionality. Kudos to the author! While you can use it for free, remember that republishing the code is subject to our House Rules.
For quick access on a chart, add this script to your favorites — learn more here.
Avoid losing contact!Don't miss out! The first and most important thing to do is to join my Discord chat now! Click here to start your adventure: discord.com/invite/ZTGpQJq 防止失联,请立即行动,加入本猫聊天群: discord.com/invite/ZTGpQJq
Disclaimer
The information and publications are not meant to be, and do not constitute, financial, investment, trading, or other types of advice or recommendations supplied or endorsed by TradingView. Read more in the Terms of Use.