1997issue C021-3
Hidden horizon assumptions in dominant-cycle readings
A published letter asked why a power-spectrum peak should match a trader's requirements rather than how the peak is computed. The reply treated the lookback as a property of dynamic-range, treated bar size as interchangeable sampling, and required a cycle-mode versus trend-mode test. Editorial reading: write those choices down before treating one dominant-cycle as the series itself.
- A power-spectrum peak names a dominant-cycle only after analysis-span, bar size, and dynamic-range have already been chosen.
- A published letter asked for a working definition of dominance and why that peak should match a trader's timeframe rather than the computation that produced it.
- The reply treated lookback as a property of the method's dynamic-range and treated daily, weekly, or hourly bars as interchangeable samples of the same observations.
- Because the series can sit in trend-mode or cycle-mode, and because cycle-drift is expected, a measured wavelength is a current reading rather than the series itself.
What the letter asked
A published letter argued that the cycle of practical interest is relative to a trader's style and preferred timeframe, which a mathematical detector does not automatically encode.
The same letter asked for the assumptions used when a technique names one cycle dominant, and for a working definition of that term. It tied dominance to a power-spectrum peak from earlier cycle writing, then asked why that peak should match a trader's requirements rather than how the peak is computed.
In the terms used here, a dominant-cycle is the single wavelength a detector treats as the strongest periodic component in a finite sample of ordered prices. Spectral-analysis is any decomposition of those observations into cycle-length or frequency components so a peak can be compared with a chosen sampling interval and horizon. The power-spectrum is a plot of strength versus cycle length, and the tallest peak is the operational stand-in for dominance.
Lookback, bar size, and dynamic-range
The reply stated that the lookback used to find a dominant-cycle is mainly a property of the measurement method's dynamic-range. Dynamic-range is the ratio of longest to shortest cycle a given detector can report without changing its internal parameters. Analysis-span is the lookback window that decides which cycle lengths can be resolved and how quickly a drifting cycle is noticed.
The reply stated that one maximum-entropy-spectrum cycle measurement remains valid across an eight-to-one span from 6 to 50 bars without adjusting internal parameters. Because the input is sampled observations, the reply stated that it matters little whether those bars are daily, weekly, or hourly.
The reply invoked amplitude-proportionality, the claim that a longer measured cycle tends to carry a larger price swing when the same method is applied at another sampling interval.
Mode first, then a wavelength
The reply treated the series as switching between a trend-mode and a cycle-mode, and treated identifying the current mode as necessary before choosing entries and exits. Trend-mode is a state the reply treats as non-oscillatory drift, so a cycle-timed rule would be the wrong instrument. Cycle-mode is a state the reply treats as oscillatory, so entries and exits would be keyed to a measured wavelength.
The reply stated that measured cycles appear, disappear, and drift from one length to another. Cycle-drift is that tendency inside the same series. The useful task, on the reply's account, is to track that change as it occurs.
All readings on this track · 28 readings
- 1984Constructing maximum-entropy spectra for dominant-cycle forecasts
- 1984How to construct a maximum-entropy cycle model
- 1984Constructing a maximum-entropy forecast from a chosen lookback
- 1985Constructing period-locked half-cycle and full-cycle averages
- 1986Why Fourier windows limit dominant-cycle resolution
- 1987Assembling short-lookback maximum-entropy cycle forecasts
- 1988Why a fitted dominant cycle is not a forecast
- 1989Evaluating commodity cycle personalities with spectral histograms
- 1989Evaluating next-session cycle forecasts with stops
- 1989Constructing cycle-aged volatility trailing stops
- 1990A channel signal-to-noise gate for dominant-cycle forecasts
- 1990Year-over-year dominant cycle personality audit
- 1991Cyclic entry from a locked dominant-cycle phase
- 1992Stationarity states on synchronized futures spectral contours
- 1997Hidden horizon assumptions in dominant-cycle readings
- 1997When market cycles are absent more than present
- 1997A spectral estimator that retunes indicators to the measured cycle
- 2000Constructing a Hilbert dominant cycle and a maximum-entropy refinement
- 2000Switch trend and cycle indicators after a half-cycle dwell test
- 2000Constructing a dominant-cycle squelch trend filter
- 2000Phasor displays for dominant-cycle construction
- 2002Low-lag trendline from elliptic and dominant-cycle notches
- 2004Spectral peaks are mode diagnostics, not forecasts
- 2004Compressive last-stage oscillator construction
- 2013Constructing trend failure curves from qualified-trend transitions
- 2014Lookback range, a two-lag smoother, and next-bar fills
- 2014Constructing a MESA stochastic with roofing and SuperSmoother filters
- 2016Constructing spectral heatmaps for dominant market cycles