Chebyshev Filters

Chebyshev Filters smooths price with a real signal-processing design rather than a lookalike: cascaded biquad sections computed from the textbook recipe, normalized so the cascade sits on price. It is the definitive clean charting build of Chebyshev filters, offering both variants — Type I buys the steepest available roll-off with a small passband ripple, Type II keeps what it passes flat and shifts the ripple into the band it rejects.

How to Trade the Chebyshev Filters?

• Slope color: the line turns bullish while rising and bearish while falling — the trend-baseline read — and slope reversals carry their own alerts.
• Price crossings: crossovers and crossunders of the filter work like those of any moving-average baseline, with optional triangle markers and alerts.
• Gradient fill: shading between price and the filter keeps the current side visible at a glance.

Choose a cutoff near the shortest swing being traded; the Source input also accepts another indicator's output, making pre-smoothing a series a first-class use.

Chebyshev Filters Settings

• Source (default close): the series to smooth.
• Filter Type (default Type I (passband ripple)): where the ripple lives. At the same cutoff Type II is smoother and slower, since its cutoff marks full rejection rather than the passband edge.
• Cutoff Period (default 20): the trend/noise boundary in bars — slower cycles pass, faster ones are attenuated.
• Order (default 3): how sharply the boundary is enforced; each added order cuts more decisively but adds lag and ringing.
• Passband Ripple (dB) (default 0.5): Type I only — a larger allowance buys a steeper roll-off.
• Stopband Attenuation (dB) (default 40): Type II only — minimum rejection beyond the cutoff.
• Style: Slope Trend Coloring (default on), the three colors, Price / Filter Gradient Fill (default on), and Price Crossing Markers (default off).

Frequently Asked Questions

Chebyshev or Butterworth?

The classic trade. A Butterworth filter is maximally flat — no ripple anywhere — with a gentler transition, while a Chebyshev of the same order cuts noise off more sharply and pays in ripple.

Type I or Type II?

Type I when the priority is the sharpest cutoff, accepting that kept swings may be passed slightly unevenly. Type II when trend fidelity matters more: its passband is flat and the ripple lives in frequencies already being rejected.

What causes the overshoot after sharp reversals?

Ringing — the cost of a steep filter. It grows with the Order and, in Type I, with the ripple allowance. Start at a low order (2 to 4 covers most charting) and step up only when noise keeps bleeding through.