In an interview (http://bettersystemtrader.com/048-john-ehlers/) with John Ehlers, I heard him being asked what his favorite indicators are.

His top indicator is the decycler. I didn’t find anything about it on PRT, but the code can be found on Tradingview. Maybe a good addition Prorealcode?

https://de.tradingview.com/script/ZuIZPR4q-Ehlers-Simple-Decycler/
https://de.tradingview.com/script/5xelSGhd-Ehlers-Decycler-Oscillator/

//@version=3
// Copyright (c) 2019-present, Alex Orekhov (everget)
// Ehlers Simple Decycler script may be freely distributed under the MIT license.
study(“Ehlers Simple Decycler”, shorttitle=”Decycler”, overlay=true)

highpassLength = input(title=”Highpass Period”, type=integer, defval=125)
upperPercent = input(title=”Upper Band % Shift”, type=float, minval=0, step=0.1, defval=0.5)
lowerPercent = input(title=”Lower Band % Shift”, type=float, minval=0, step=0.1, defval=0.5)
src = input(title=”Source”, type=source, defval=close)
highlightMovements = input(title=”Highlight Decycler Movements ?”, type=bool, defval=true)

PI = 2 * asin(1)

// High-pass Filter
alphaArg = 2 * PI / (highpassLength * sqrt(2))

alpha = 0.0
alpha := cos(alphaArg) != 0
? (cos(alphaArg) + sin(alphaArg) – 1) / cos(alphaArg)
: nz(alpha[1])

hp = 0.0
hp := pow(1 – (alpha / 2), 2) * (src – 2 * nz(src[1]) + nz(src[2])) + 2 * (1 – alpha) * nz(hp[1]) – pow(1 – alpha, 2) * nz(hp[2])

decycler = src – hp

decyclerColor = highlightMovements ? (decycler >= decycler[1] ? green : red) : #741b47
plot(decycler, title=”Decycler”, linewidth=2, color=decyclerColor, transp=0)

upperBand = (1 + upperPercent / 100) * decycler
lowerBand = (1 – lowerPercent / 100) * decycler

bandColor = #138484
upperBandPlot = plot(upperBand, title=”Upper”, color=bandColor)
lowerBandPlot = plot(lowerBand, title=”Lower”, color=bandColor)
fill(upperBandPlot, lowerBandPlot, title=”Background”, color=color(#ffd966, 84))

//@version=3
// Copyright (c) 2019-present, Alex Orekhov (everget)
// Ehlers Decycler Oscillator script may be freely distributed under the MIT license.
study(“Ehlers Decycler Oscillator”, shorttitle=”Decycler Oscillator”)

hpPeriod = input(title=”High-pass Filter Period”, type=integer, defval=125)
k = input(title=”K Multiplier”, type=float, step=0.1, defval=1)
hpPeriod2 = input(title=”High-pass Filter Period 2″, type=integer, defval=100)
k2 = input(title=”K Multiplier 2″, type=float, step=0.1, defval=1.2)
src = input(title=”Source”, type=source, defval=close)
highlightCrossovers = input(title=”Highlight Crossovers ?”, type=bool, defval=true)
highlightZeroCrossovers = input(title=”Highlight Zero Line Crossovers ?”, type=bool, defval=false)
applyFilling = input(title=”Apply Ribbon Filling ?”, type=bool, defval=false)

PI = 2 * asin(1)

// High-pass Filter
_hp(src, hpPeriod, mult) =>
alphaArg = 2 * PI / (mult * hpPeriod * sqrt(2))

alpha = 0.0
alpha := cos(alphaArg) != 0
? (cos(alphaArg) + sin(alphaArg) – 1) / cos(alphaArg)
: nz(alpha[1])

hp = 0.0
hp := pow(1 – (alpha / 2), 2) * (src – 2 * nz(src[1]) + nz(src[2])) + 2 * (1 – alpha) * nz(hp[1]) – pow(1 – alpha, 2) * nz(hp[2])
hp

hp = _hp(src, hpPeriod, 1)
decycler = src – hp
decosc = 100 * k * _hp(decycler, hpPeriod, 0.5) / src

hp2 = _hp(src, hpPeriod2, 1)
decycler2 = src – hp2
decosc2 = 100 * k2 * _hp(decycler2, hpPeriod2, 0.5) / src

trendColor = decosc2 > decosc ? #0ebb23 : red

decoscColor = applyFilling ? trendColor : #ff5048
decosc2Color = applyFilling ? trendColor : #f5c75e

decoscPlot = plot(decosc, title=”1″, linewidth=2, color=decoscColor, transp=0)
decosc2Plot = plot(decosc2, title=”2″, linewidth=2, color=decosc2Color, transp=0)
hline(0, title=”Zero Level”, linestyle=dotted)

transparent = color(white, 100)

fillColor = applyFilling ? trendColor : transparent
fill(decoscPlot, decosc2Plot, color=fillColor, transp=70)

zeroCrossBgColor = highlightZeroCrossovers ? (decosc > 0 or decosc2 > 0 ? green : red) : transparent
bgcolor(zeroCrossBgColor, transp=85)

plotshape(highlightCrossovers and crossover(decosc, decosc2) ? avg(decosc, decosc[1]) : na, title=”Crossover”, location=location.absolute, style=shape.circle, size=size.tiny, color=green, transp=0)
plotshape(highlightCrossovers and crossunder(decosc, decosc2) ? avg(decosc, decosc[1]) : na, title=”Crossunder”, location=location.absolute, style=shape.circle, size=size.tiny, color=red, transp=0)