D_DSP (Detrended Synthetic Price)

D_DSP.efs  
EFSLibrary - Discussion Board  

File Name: D_DSP.efs

Description:
This Indicator plots D_DSP (Detrended Synthetic Price) indicator

Formula Parameters:

• Length: 14

Notes:

Detrended Synthetic Price is a function that is in phase with the dominant cycle of real price data. This DSP is computed by subtracting a half-cycle exponential moving average (EMA) from the quarter cycle
exponential moving average.
See "MESA and Trading Market Cycles" by John Ehlers pages 64 - 70.

Download File:
D_DSP.efs


EFS Code:

/*********************************

Provided By:  

    eSignal (Copyright c eSignal), a division of Interactive Data 
    Corporation. 2008. All rights reserved. This sample eSignal 
    Formula Script (EFS) is for educational purposes only and may be 
    modified and saved under a new file name.  eSignal is not responsible
    for the functionality once modified.  eSignal reserves the right 
    to modify and overwrite this EFS file with each new release.

Description:        

    This Indicator plots D_DSP (Detrended Synthetic Price) indicator

Version:            1.0  09/30/2008

Notes:

    Detrended Synthetic Price is a function that is in phase with the 
    dominant cycle of real price data. This DSP is computed by subtracting 
    a half-cycle exponential moving average (EMA) from the quarter cycle 
    exponential moving average.

    See "MESA and Trading Market Cycles" by John Ehlers pages 64 - 70. 


Formula Parameters:                     Default:

    Length                              14                              

**********************************/


var fpArray = new Array();

function preMain() {
    setPriceStudy(false);
    setStudyTitle("Detrended Synthetic Price");
    setCursorLabelName("D-DSP", 0);
    setDefaultBarFgColor(Color.blue, 0);
    
    var x=0;
    fpArray[x] = new FunctionParameter("Length", FunctionParameter.NUMBER);
    with(fpArray[x++]) {
        setLowerLimit(2);  
        setDefault(14);
    }
}

var bInit = false;
var xRes   = null;

function main(Length) {
    var nBarState = getBarState();
    if (nBarState == BARSTATE_ALLBARS) {
        if (Length == null) Length = 14;
    }

    if (bInit == false) {
        xRes = efsInternal("calc", Length, inv("d"));
        addBand(0, PS_SOLID, 1, Color.red, "ZeroLine");
        bInit = true;
    }
    return xRes.getValue(0);
}

var xInit = false;
var xPrice = null;
var xEMA1 = null;
var xEMA2 = null;

function calc(Length, Interval) {
    if(xInit == false) {
        xPrice = hl2();
        xEMA1 = ema(Length, xPrice);
        xEMA2 = ema(Length*2, xPrice);
        xInit = true;
    }
    var nEMA1 = xEMA1.getValue(-1);
    var nEMA2 = xEMA2.getValue(-1);
    if(nEMA1 == null || nEMA2 == null) return;
    return nEMA1 - nEMA2;
}