Noise and filtering
Noise and filtering is part of the Nanopore Wiki learning path. Noise and filtering determine whether nanopore events can be resolved and whether extracted features remain faithful to the original signal.
Core concepts
- Thermal, shot, capacitive, surface, and low-frequency noise can all affect nanopore recordings.
- Low-pass filtering reduces high-frequency noise but broadens rapid events.
- Sampling rate should be chosen relative to bandwidth and expected event duration.
- Noise should be reported with the same acquisition settings used for analysis.
Scientific basis
- Thermal, shot, capacitive, surface, and low-frequency noise can all affect nanopore recordings.
- Low-pass filtering reduces high-frequency noise but broadens rapid events.
- Interpretations should be tied to measurable quantities, experimental controls, and documented analysis settings.
- Claims should distinguish direct observations from downstream inference.
Quality workflow
| Step | Description |
|---|---|
| 1 | Record blank baseline before sample addition. |
| 2 | Estimate baseline mean, drift, RMS noise, and obvious interference. |
| 3 | Choose bandwidth and event threshold based on the scientific question. |
| 4 | Verify that conclusions are robust to reasonable filtering choices. |
Typical applications
- Event detection thresholds.
- Comparison across pore systems and instruments.
- Troubleshooting unstable recordings.
Quality checks
- Record platform, pore or flow-cell type, chemistry, voltage or acquisition settings, and software versions.
- Use negative controls, positive controls, and replicate measurements where the claim depends on specificity.
- Report limitations such as noise, bias, sample degradation, pore instability, or model-dependent analysis.
- Separate physical mechanism, signal-processing choice, and biological interpretation.
Interpretation limits
- Using aggressive filters to hide poor experimental stability.
- Changing filtering parameters between samples without reporting it.
- A single result should not be generalized beyond the sample, protocol, instrument state, and analysis pipeline used.
- Medical, legal, regulatory, or commercial decisions require domain-specific validation beyond this educational summary.