# amplitudeToDecibels(_:zeroReference:) Returns double-precision amplitude values converted to decibel values. ``` static func amplitudeToDecibels(_ amplitude: U, zeroReference: Double) -> [Double] where U : AccelerateBuffer, U.Element == Double ``` ## Parameters `amplitude` The input vector that defines the amplitude values. `zeroReference` The zero reference that the function uses for the conversion. ## Discussion The function uses the following calculation to perform the conversion: ```swift alpha = 20; for (n = 0; n < N; ++n) C[n] = alpha * log10(A[n] / B[0]); ``` --- 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)