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Fourier Extrapolator

Forex Fourier Extrapolator is a type of forecasting indicator used in MT4/MT5 trading platforms that applies Fourier Transform–based curve fitting to price data and then projects the fitted waveform into the future. It is a prediction-style tool — not a standard indicator — and is often included in advanced “cycle analysis” or “curve extrapolation” systems.

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What a Forex Fourier Extrapolator Is

It is an indicator that:

1. Applies the Fourier Transform
It decomposes recent price movement into multiple sine/cosine waves (cycles):

• high-frequency waves → fast changes
  low-frequency waves → slow trends

This is basically using math to find the “dominant cycles” in the market.

2. Reconstructs a smooth mathematical curve
It builds a fitted curve that matches past price action using:

• amplitude
  frequency
  phase

3. Extrapolates the curve into the future
Once the waveform is fitted, it projects the curve forward X bars.
This forward projection is what traders use as a forecast.

This is also why it’s called Fourier Extrapolator — it tries to predict future price movement based on cycle structure.
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What Traders Use It For

Forecasting potential reversals
Identifying dominant cycles
Predicting future swings
Visualizing smooth trend curves
Creating future projection lines (similar to Polynomial Regression Forecast but smoother)

Many versions show:

• A smoothed line of price (Fourier Fit)
  A future projection (extrapolated segment)
  Optional bands or cycle waves

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Important: It Is NOT a Reliable Predictor

Just like TMA, SATL extrapolation, or polynomial regressions:

• It recalculates, not repaints
  Forecasting is math, not price action
  The future curve is only a projection, not a signal

Price will easily deviate from the projection in volatile markets.
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"fourier_extrapolator_of_price.mq5" is the original code.
I just modified a little bit to make an ATR band indicator.