diff --git a/Modelica/Blocks/Sources.mo b/Modelica/Blocks/Sources.mo
index 143c2ee387..058c0992a8 100644
--- a/Modelica/Blocks/Sources.mo
+++ b/Modelica/Blocks/Sources.mo
@@ -941,13 +941,14 @@ The Real output y is a trapezoid signal:
equation
y = if time < startTime then wMin else
if time < (startTime + max(duration,eps)) then
- 10^(log10(wMin) + (log10(wMax) - log10(wMin))*min(1, (time-startTime)/max(duration,eps)))
+ wMin * (wMax/wMin)^min(1, (time-startTime)/max(duration,eps))
else
wMax;
annotation (defaultComponentName="logSweep",
Documentation(info="
The output y performs a logarithmic frequency sweep.
The logarithm of frequency w performs a linear ramp from log10(wMin) to log10(wMax).
+It uses wMin*(wMax/wMin)^x instead of the equivalent 10^(log10(wMin)+log10(wMax)-log10(wMin)*x) to help with unit-checking.
The output is the decimal power of this logarithmic ramp.
For time < startTime the output is equal to wMin.