Hilbert Transform Dominant Cycle Period (HT DCPERIOD)
The Real-Time Tape Measure of the Market's Hidden Rhythm
John Ehlers brought digital-signal-processing firepower to trading with the Hilbert Transform Dominant Cycle Period (HT DCPERIOD). Fixed-period indicators lag or whipsaw when the market's cycle length changes – trending slowly one week, chopping fast the next. DCPERIOD solves that by measuring the current dominant cycle wavelength bar-by-bar using phase analysis. The result? A dynamic number (typically 6–50 bars) that tells adaptive tools exactly how long the market's 'heartbeat' is right now. It's the foundation for truly responsive indicators that stretch in trends and tighten in chop.
How It Measures the Cycle
High-level flow:
- Detrend price: Remove slow drift with high-pass or EMA.
- Hilbert pair: Apply quadrature filter → InPhase and Quadrature components.
- Instantaneous phase: Compute angle from I/Q.
- Phase change: Track Δφ between bars – full 360° = one cycle.
- Period: DCPERIOD ≈ 360° / average Δφ (clamped 6–50).
Light smoothing (Wilder α ≈0.07–0.2) keeps it stable.
Libraries like TA-Lib handle the math – just plot HT_DCPERIOD.
Interpreting the Readings
Market messages:
- Rising DCPERIOD: Cycles lengthening – trending strength, lower volatility.
- Falling DCPERIOD: Cycles shortening – choppier action, volatility rising.
- Stable plateau: Locked rhythm – adaptive tools can 'tune in' confidently.
- >30–40: Slow trend mode – favor trend-following.
- <15–20: Fast cycle – mean-reversion territory.
Practical Trading Applications
How to use it:
- Adaptive MAs: Set length ≈ α × DCPERIOD (e.g., MAMA, FRAMA).
- Oscillator windows: Momentum look-back ≈ ½ × DCPERIOD.
- Swing timing: Enter near calculated troughs (phase tools) when DCPERIOD stable.
- Regime filter: Trend systems when DCPERIOD ≥20; mean-revert below.
Rule of thumb: half period for momentum, full for smoothing.
Parameter Tips
Main tweaks:
- Input: Median price ((H+L)/2) reduces noise.
- Bounds: Clamp 6–50 to avoid extremes.
- Smoothing: Light EMA(5) on output for cleaner line.
Strengths and Caveats
The Wins
- True market-adaptive cycle measurement.
- Forward-looking phase logic – low lag.
- Powers sophisticated adaptive indicators.
- No subjective period guessing.
The Gotchas
- Complex internals – black box for many.
- Gaps/low-volume distort quadrature.
- Needs ~50-bar warm-up for stability.
- Diagnostic only – no direct signals.
Your DCPERIOD Checklist
- Use platform library (TA-Lib HT_DCPERIOD).
- Feed median price for cleaner input.
- Clamp and lightly smooth output.
- Drive adaptive tools with current value.
- Combine with phase (DCPHASE) for timing.
- Monitor for regime shifts (rising/falling).
Key Takeaways
HT DCPERIOD measures current dominant market cycle length via Hilbert phase.
Rising = lengthening cycles (trend), falling = shortening (chop).
Powers truly adaptive MAs, oscillators, and swing timing.
Real-time rhythm detector – no fixed periods needed.
Use libraries, feed clean data, drive other tools – and stay in sync with the market's heartbeat. Stay phased and trade strong!
Hilbert Transform Dominant Cycle Period (HT DCPERIOD)
The Real-Time Tape Measure of the Market's Hidden Rhythm
John Ehlers brought digital-signal-processing firepower to trading with the Hilbert Transform Dominant Cycle Period (HT DCPERIOD). Fixed-period indicators lag or whipsaw when the market's cycle length changes – trending slowly one week, chopping fast the next. DCPERIOD solves that by measuring the current dominant cycle wavelength bar-by-bar using phase analysis. The result? A dynamic number (typically 6–50 bars) that tells adaptive tools exactly how long the market's 'heartbeat' is right now. It's the foundation for truly responsive indicators that stretch in trends and tighten in chop.
Table of Contents
How It Measures the Cycle
High-level flow:
- Detrend price: Remove slow drift with high-pass or EMA.
- Hilbert pair: Apply quadrature filter → InPhase and Quadrature components.
- Instantaneous phase: Compute angle from I/Q.
- Phase change: Track Δφ between bars – full 360° = one cycle.
- Period: DCPERIOD ≈ 360° / average Δφ (clamped 6–50).
Light smoothing (Wilder α ≈0.07–0.2) keeps it stable.
Libraries like TA-Lib handle the math – just plot HT_DCPERIOD.
Interpreting the Readings
Market messages:
- Rising DCPERIOD: Cycles lengthening – trending strength, lower volatility.
- Falling DCPERIOD: Cycles shortening – choppier action, volatility rising.
- Stable plateau: Locked rhythm – adaptive tools can 'tune in' confidently.
- >30–40: Slow trend mode – favor trend-following.
- <15–20: Fast cycle – mean-reversion territory.
Practical Trading Applications
How to use it:
- Adaptive MAs: Set length ≈ α × DCPERIOD (e.g., MAMA, FRAMA).
- Oscillator windows: Momentum look-back ≈ ½ × DCPERIOD.
- Swing timing: Enter near calculated troughs (phase tools) when DCPERIOD stable.
- Regime filter: Trend systems when DCPERIOD ≥20; mean-revert below.
Rule of thumb: half period for momentum, full for smoothing.
Parameter Tips
Main tweaks:
- Input: Median price ((H+L)/2) reduces noise.
- Bounds: Clamp 6–50 to avoid extremes.
- Smoothing: Light EMA(5) on output for cleaner line.
Strengths and Caveats
The Wins
- True market-adaptive cycle measurement.
- Forward-looking phase logic – low lag.
- Powers sophisticated adaptive indicators.
- No subjective period guessing.
The Gotchas
- Complex internals – black box for many.
- Gaps/low-volume distort quadrature.
- Needs ~50-bar warm-up for stability.
- Diagnostic only – no direct signals.
Your DCPERIOD Checklist
- Use platform library (TA-Lib HT_DCPERIOD).
- Feed median price for cleaner input.
- Clamp and lightly smooth output.
- Drive adaptive tools with current value.
- Combine with phase (DCPHASE) for timing.
- Monitor for regime shifts (rising/falling).
Key Takeaways
HT DCPERIOD measures current dominant market cycle length via Hilbert phase.
Rising = lengthening cycles (trend), falling = shortening (chop).
Powers truly adaptive MAs, oscillators, and swing timing.
Real-time rhythm detector – no fixed periods needed.
Use libraries, feed clean data, drive other tools – and stay in sync with the market's heartbeat. Stay phased and trade strong!
Related Terms
Apply This Knowledge
Ready to put Hilbert Transform Dominant Cycle Period (HT DCPERIOD) into practice? Use our tools to analyze your portfolio and explore market opportunities.
This content is also available on our main website for public access.