Fix mistake in decibel conversion

chapters/annotations.tex

@@ -221,7 +221,7 @@ \subsubsection{Axis Properties}\label{axis-properties}
 \end{lstlisting}%
 \index{dB@\robustinline{dB} (decibel axis scale)}
 
-The mandatory \lstinline!order! is used to define a tick label conversion according to $y \mapsto \frac{\operatorname{log}_{10}(y)}{\text{\lstinline!order!}}$.
+The mandatory \lstinline!order! is used to define a tick label conversion according to $y \mapsto \text{\lstinline!order!}\, \operatorname{log}_{10}(y)}$.
 This mapping shall be applied before presenting values in tick labels.
 It is recommended that value of \lstinline!order! is somehow indicated on the axis or its tick labels, for example by presenting a major tick label as $8\, \mathrm{dB}_{20}$.
 Major axis ticks are preferred at integer converted values, and minor ticks should be placed at evenly distributed converted values (similar to a linear axis scale).