diff --git a/src/scgenerator/noise.py b/src/scgenerator/noise.py
index a75c49d..290e5cd 100644
--- a/src/scgenerator/noise.py
+++ b/src/scgenerator/noise.py
@@ -183,7 +183,7 @@ class NoiseMeasurement:
             if self.freq[0] == 0:
                 interp[0] = self.psd[0]
         else:
-            interp = np.interp(f, self.freq, self.psd, left=0, right=self.psd[-1])
+            interp = np.interp(f, self.freq, self.psd, left=self.psd[0], right=self.psd[-1])
         return f, interp
 
     def time_series(
diff --git a/src/scgenerator/physics/units.py b/src/scgenerator/physics/units.py
index 959e1a3..18a3633 100644
--- a/src/scgenerator/physics/units.py
+++ b/src/scgenerator/physics/units.py
@@ -94,7 +94,7 @@ def W_to_Vm(n0: float, effective_area: float) -> float:
 
 
 def unit_formatter(
-    unit: str, decimals: int = 1, vmin: float | None = 1e-28
+    unit: str, decimals: int = 3, vmin: float | None = 1e-28
 ) -> Callable[[float | int], str]:
     if not unit:
 
@@ -130,6 +130,11 @@ def unit_formatter(
         else:
             return formatter(val)
 
+    def _format_mpl(val, _):
+        return _format(val)
+
+    setattr(_format, "for_mpl", _format_mpl)
+
     return _format