diff --git a/src/backscattering_analyzer/display.py b/src/backscattering_analyzer/display.py
index 7ab977e..4c09d3a 100644
--- a/src/backscattering_analyzer/display.py
+++ b/src/backscattering_analyzer/display.py
@@ -21,33 +21,40 @@ def show_projection(
         ylabel,
     )
 
-    excited = experiment.data.excited.sensibility.psd().sqrt()
     reference = experiment.data.reference.sensibility.psd().sqrt()
-    loglog(
-        experiment.projection_excited.x,
-        experiment.projection_excited.y,
-        label=_("projection with excitation"),
-    )  # type: ignore[ReportUnusedCallResult]
+    try:
+        excited = experiment.data.excited.sensibility.psd().sqrt()
+        loglog(
+            experiment.projection_excited.x,
+            experiment.projection_excited.y,
+            label=_("projection with excitation"),
+        )  # type: ignore[ReportUnusedCallResult]
+        loglog(
+            excited.x,
+            excited.y,
+            label=_("detected sensibility with excitation"),
+        )  # type: ignore[ReportUnusedCallResult]
+        loglog(
+            (experiment.projection_excited + reference).x,
+            (experiment.projection_excited + reference).y,
+            label=_(
+                "sum: no excitation and projection with excitation"
+            ),
+        )  # type: ignore[ReportUnusedCallResult]
+    except AttributeError:
+        logger.debug(
+            _("no excited signal, will only show reference signal")
+        )
     loglog(
         experiment.projection_reference.x,
         experiment.projection_reference.y,
         label=_("projection without excitation"),
     )  # type: ignore[ReportUnunsedCallResult]
-    loglog(
-        excited.x,
-        excited.y,
-        label=_("detected sensibility with excitation"),
-    )  # type: ignore[ReportUnusedCallResult]
     loglog(
         reference.x,
         reference.y,
         label=_("detected sensibility without excitation"),
     )  # type: ignore[ReportUnusedCallResult]
-    loglog(
-        (experiment.projection_excited + reference).x,
-        (experiment.projection_excited + reference).y,
-        label=_("sum: no excitation and projection with excitation"),
-    )  # type: ignore[ReportUnusedCallResult]
     legend()  # type: ignore[ReportUnusedCallResult]
     title(experiment.bench)  #  type: ignore[ReportUnusedCallResult]
     xlabel(_("frequency (Hz)"))  # type: ignore[ReportUnusedCallResult]
diff --git a/src/backscattering_analyzer/experiment.py b/src/backscattering_analyzer/experiment.py
index 360d424..9ca3b64 100644
--- a/src/backscattering_analyzer/experiment.py
+++ b/src/backscattering_analyzer/experiment.py
@@ -203,7 +203,7 @@ class Experiment:
                 self.calibrations,
                 vibration_frequency,
             )
-        except ValueError:
+        except AttributeError:
             pass
         logger.debug(_("movement processed"))
 
@@ -255,12 +255,15 @@ class Experiment:
             )
             self.factors = self.fit_factors()
 
-        self.projection_excited = self.compute_projection(
-            AcquisitionType.EXCITED,
-        )
         self.projection_reference = self.compute_projection(
             AcquisitionType.REFERENCE,
         )
+        try:
+            self.projection_excited = self.compute_projection(
+                AcquisitionType.EXCITED,
+            )
+        except Exception:
+            pass
         logger.debug(_("end of experiment initialisation"))
 
     def get_factors(
@@ -294,7 +297,7 @@ class Experiment:
                 )
                 raise Exception(
                     _(
-                        "no excited signal given, cannot get facotrs "
+                        "no excited signal given, cannot get factors "
                         + "of the excited signal"
                     )
                 )