---
title: responderClockFrequencyOffset
framework: nearbyinteraction
role: symbol
role_heading: Instance Property
path: nearbyinteraction/nidltdoameasurement/responderclockfrequencyoffset-8wu5r
---

# responderClockFrequencyOffset

The clock frequency offset of the responder anchor relative to the initiator anchor.

## Declaration

```swift
var responderClockFrequencyOffset: Double? { get }
```

## Discussion

Discussion This property represents relative clock frequency information between the responder anchor and initiator anchor. The relative difference is a key part of calculating precise distances. Drift between the clocks of anchors represents a persistent issue in DL-TDOA deployments that the responder clock frequency offset helps mitigate. The value is dimensionless because it expresses a ratio rather than an absolute frequency. The ratio compares the responder’s clock frequency to the initiator’s clock frequency as a fractional difference. You can use the difference as necessary while implementing your DL-TDOA positioning engine.

## See Also

### Evaluating the message

- [measurementType](nearbyinteraction/nidltdoameasurement/measurementtype.md)
- [carrierFrequencyOffset](nearbyinteraction/nidltdoameasurement/carrierfrequencyoffset.md)