angular_resample — ACOUSTICS order op

• 데이터 종류: signal → table

• 호출: import fullseye as fs; fs.ledger.angular_resample(x, rate, rpm, samples_per_rev=64)(구현을 직접 호출하려면 import acoustics; acoustics.angular_resample(x, rate, rpm, samples_per_rev=64), 원장에서 가져오려면 opsacoustics.get("angular_resample"))

사용법

시간 기록을 축 회전각 축으로 재표본화합니다(계산 차수 추적).

> 아래 상세 설명은 원문입니다 —— 요약과 제목은 번역되어 있습니다.

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.

자세한 사용 가이드

• acoustic_condition_monitoring 패밀리 가이드

참고(샘플 데이터·문헌)

• 샘플 데이터 카탈로그(DL URL / 라이선스) —— 2-D 는 skimage.data(BSD/public)+ 합성, 3-D 는 실데이터 소스(Stanford/PDS 등)의 DL URL.

• 연산자의 내력·참고문헌 —— 이 연산자 족의 바탕이 된 연구/기법의 출처.

• 알고리즘의 정전(저자·연도)과 용도는 위의 패밀리 사용 가이드에 적혀 있습니다.

실행 가능한 예제(이 연산자를 실제로 호출하는 검증된 샘플)

• acoustic_condition_monitoring — py -3.11 examples/acoustic_condition_monitoring.py

타입이 이어지는 다음 연산자(table 를 입력으로 받는 것)

istft

같은 카테고리(order)

order_spectrum


*Provenance: acoustics.py — ACOUSTICS 연산자 레지스트리. 이 op 노트는 tools/opdocs.py md 가 자동 생성합니다(직접 편집하지 마세요).*

© 2026 Kazufumi Furuse — Fullseye operator documentation. Licensed under Apache-2.0.