# responderClockFrequencyOffset The clock frequency offset of the responder anchor relative to the initiator anchor. ``` var responderClockFrequencyOffset: Double? { get } ``` ## 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. --- Copyright © 2026 Apple Inc. All rights reserved. | [Terms of Use](https://www.apple.com/legal/internet-services/terms/site.html) | [Privacy Policy](https://www.apple.com/privacy/privacy-policy)