---
title: backgroundNoise
framework: sensorkit
role: symbol
role_heading: Instance Property
path: sensorkit/srphotoplethysmogramopticalsample/backgroundnoise
---

# backgroundNoise

An estimated timeseries of ambient noise intrusion.

## Declaration

```occ
@property (nonatomic, strong, readonly, nullable) NSNumber * backgroundNoise;
```

## Discussion

Discussion The sensor’s estimate of ambient noise intrusion in the normalizedReflectance signal (Normalized Units).

## See Also

### Accessing optical data

- [emitter](sensorkit/srphotoplethysmogramopticalsample/emitter.md)
- [activePhotodiodeIndexes](sensorkit/srphotoplethysmogramopticalsample/activephotodiodeindexes.md)
- [signalIdentifier](sensorkit/srphotoplethysmogramopticalsample/signalidentifier.md)
- [nominalWavelength](sensorkit/srphotoplethysmogramopticalsample/nominalwavelength.md)
- [effectiveWavelength](sensorkit/srphotoplethysmogramopticalsample/effectivewavelength.md)
- [samplingFrequency](sensorkit/srphotoplethysmogramopticalsample/samplingfrequency.md)
- [nanosecondsSinceStart](sensorkit/srphotoplethysmogramopticalsample/nanosecondssincestart.md)
- [conditions](sensorkit/srphotoplethysmogramopticalsample/conditions.md)
- [SRPhotoplethysmogramOpticalSample.Condition](sensorkit/srphotoplethysmogramopticalsample/condition.md)
- [whiteNoise](sensorkit/srphotoplethysmogramopticalsample/whitenoise.md)
- [pinkNoise](sensorkit/srphotoplethysmogramopticalsample/pinknoise.md)
- [backgroundNoiseOffset](sensorkit/srphotoplethysmogramopticalsample/backgroundnoiseoffset.md)
- [normalizedReflectance](sensorkit/srphotoplethysmogramopticalsample/normalizedreflectance-9aidm.md)