order op• 資料種類:signal → table
• 呼叫: import fullseye as fs; fs.ledger.angular_resample(x, rate, rpm, samples_per_rev=64)(要直接呼叫實作,import acoustics; acoustics.angular_resample(x, rate, rpm, samples_per_rev=64);從台帳取用則 opsacoustics.get("angular_resample"))
把時間記錄重取樣到軸角軸上(計算階次追蹤)。
> 以下的詳細說明為原文 —— 摘要與標題已翻譯。
Under a changing shaft speed, a component locked to the shaft has a moving frequency and smears across the spectrum, while a structural resonance stays put. Resample the record so the samples are equally spaced in shaft angle instead of in time and the situation reverses exactly: the order becomes a single line and the resonance smears.
rpm is either a single number (constant speed — the transform is then a pure rescaling) or a per-sample array on the same clock as the signal. The cumulative revolution count is the trapezoidal integral of rpm/60, and the signal is linearly interpolated onto a uniform grid in it.
Returns a dict — an angle-domain record is not put into circulation as a plain signal, deliberately. Its samples are indexed by angle, not time, so handing it to any op that takes a rate would produce frequencies in Hz from an axis measured in revolutions: no exception, no NaN, just wrong numbers. (Same judgement, and the same reason, as motionmag.motion_magnify not exposing a bare video adapter.) The dict carries signal, angle_rev, samples_per_rev, revolutions (total), whole_revolutions, rate (the original time-domain one, for provenance), mean_rpm, max_order.
max_order is samples_per_rev / 2 — the Nyquist of the *angle* axis.
Measured: a pure order-3.5 component on a 600 -> 1800 rpm ramp, resampled at 64 samples/rev over 78 whole revolutions, reads amplitude 0.999371 in a single bin of the order spectrum; the same component in the ordinary spectrum peaks at 0.070203 and is 66.5 Hz wide.
Raises ValueError: everything _as_signal refuses, a non-positive or wrong-length rpm, samples_per_rev outside [2, 65536], an output over MAX_ANGULAR_SAMPLES, fewer than one complete revolution in the record, and — the aliasing refusal — a samples_per_rev whose implied Nyquist order needs content above the time-domain Nyquist. Asking for 64 samples/rev on a shaft turning at 30 Hz means representing 960 Hz, which a 100 Hz recording does not contain; the resampler would happily manufacture it from the interpolation.
• acoustic_condition_monitoring 族使用指南
• 範例資料目錄(下載 URL / 授權) —— 2-D 用 skimage.data(BSD/公有領域)加合成圖,3-D 給出真實資料源(Stanford/PDS 等)的下載 URL。
• 運算子來歷與參考文獻 —— 該運算子族所依據的研究/方法出處。
• 演算法的正典(作者、年份)與用途見上面的族使用指南。
• acoustic_condition_monitoring — py -3.11 examples/acoustic_condition_monitoring.py
table 作為輸入)order)*Provenance: acoustics.py — ACOUSTICS 運算子登記表。本條目由 tools/opdocs.py md 自動產生(請勿手動編輯)。*
© 2026 Kazufumi Furuse — Fullseye operator documentation. Licensed under Apache-2.0.