scope.getWaveform()

scope.getWaveform(options) → capture | false

Captures a waveform on a channel and optionally computes an FFT with band-pass filtering and envelope demodulation.

Performs a capture and prepares the spectrum that subsequent scope.getPeak() and scope.getAmplitudes() calls will read from. The single argument is an options object:

Option	Type	Meaning
`ch`	number	Input channel index (e.g. `0`).
`osr`	number	Oversampling ratio — controls the effective sample rate / bandwidth (e.g. `64`, `128`, `4096`). Higher OSR = lower bandwidth, finer low-frequency resolution.
`size`	number	Number of samples in the capture (e.g. `2048`, `4096`). More samples = finer frequency bins.
`fft`	boolean	Compute an FFT of the capture.
`bandpass`	boolean	Apply a band-pass filter between `fMin` and `fMax` before analysis.
`fMin`	number (Hz)	Lower frequency bound. Setting 3–4 kHz on an enveloped capture filters for just bearing faults.
`fMax`	number (Hz)	Upper frequency bound.
`demod`	boolean	Enable envelope demodulation (amplitude demodulation), the standard technique for exposing repetitive bearing-impact frequencies.
`demodRatio`	number	Demodulation ratio (e.g. `32`, `64`).

Capture recipes from the factory examples:

High-frequency capture for lubrication-film health (degraded lubrication causes metal-to-metal contact producing high-frequency vibration):

scope.getWaveform({ "ch":0, "osr":64, "size":4096, "fft":true,
                    "bandpass":false, "fMin":0, "fMax":12000,
                    "demod":false, "demodRatio":1 });

Enveloped capture for bearing fault diagnosis:

scope.getWaveform({ "ch":0, "osr":64, "size":2048, "fft":true,
                    "bandpass":true, "fMin":500, "fMax":32000,
                    "demod":true, "demodRatio":64 });

Narrow capture around line frequency for precise speed measurement:

scope.getWaveform({ "ch":0, "osr":4096, "size":4096, "fft":true,
                    "bandpass":false, "fMin":120, "fMax":190,
                    "demod":false, "demodRatio":8 });

The return value is truthy on a successful capture — check it before trusting the amplitudes extracted afterwards, and log the value on failure.

Arguments

Name	Type	Required	Default	Description
options	object	yes	—	Capture configuration — see the option table in the description.

Returns

capture | false Truthy capture handle on success, false/error value on a failed capture.

Example

let cap = scope.getWaveform({ "ch": 0, "osr": 64, "size": 2048, "fft": true,
  "bandpass": true, "fMin": 500, "fMax": 32000, "demod": true, "demodRatio": 64 });

if(cap){
  // spectrum ready — use scope.getPeak / scope.getAmplitudes
} else {
  print("Failed capture:", cap);
}

scope.getWaveform()

Arguments

Returns

Example

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