diff --git a/schainpy/model/graphics/figure.py b/schainpy/model/graphics/figure.py
index 1b8dc8a..09f90d5 100644
--- a/schainpy/model/graphics/figure.py
+++ b/schainpy/model/graphics/figure.py
@@ -197,6 +197,7 @@ class Axes:
         self.plot = None
         
         self.__firsttime = True
+        self.idlineList = []
         
     def setText(self, text):
         
@@ -244,12 +245,26 @@ class Axes:
                                                     ylabel=ylabel,
                                                     title=title,
                                                   **kwargs)
+
+            self.idlineList.append(0)
             self.__firsttime = False
             return
                     
         self.__driver.pline(self.plot, x, y, xlabel=xlabel,
                                                     ylabel=ylabel,
                                                     title=title)
+
+    def addpline(self, x, y, idline, **kwargs):
+        lines = self.ax.lines
+        
+        if idline in self.idlineList:
+            self.__driver.set_linedata(self.ax, x, y, idline)
+        
+        if  idline not in(self.idlineList):
+            self.__driver.addpline(self.ax, x, y, **kwargs)
+            self.idlineList.append(idline)
+
+        return
         
     def pmultiline(self, x, y,
                    xmin=None, xmax=None,
diff --git a/schainpy/model/graphics/mpldriver.py b/schainpy/model/graphics/mpldriver.py
index 9a3b784..c0dd4cc 100644
--- a/schainpy/model/graphics/mpldriver.py
+++ b/schainpy/model/graphics/mpldriver.py
@@ -130,7 +130,14 @@ def pline(iplot, x, y, xlabel='', ylabel='', title=''):
     
     printLabels(ax, xlabel, ylabel, title)
     
-    iplot.set_data(x, y)
+    set_linedata(ax, x, y, idline=0)
+
+def addpline(ax, x, y, color, linestyle, lw):
+    ax.plot(x,y,color=color,linestyle=linestyle,lw=lw)
+    
+    
+def set_linedata(ax, x, y, idline):
+    ax.lines[idline].set_data(x,y)
 
 def createPmultiline(ax, x, y, xmin, xmax, ymin, ymax, xlabel='', ylabel='', title='', legendlabels=None,
                 ticksize=9, xtick_visible=True, ytick_visible=True,
diff --git a/schainpy/model/jroplot.py b/schainpy/model/jroplot.py
index 02d0789..0760306 100644
--- a/schainpy/model/jroplot.py
+++ b/schainpy/model/jroplot.py
@@ -465,6 +465,9 @@ class SpectraPlot(Figure):
                         xlabel='dB', ylabel='', title='',
                         ytick_visible=False,
                         grid='x')
+                
+                noiseline = numpy.repeat(noise[i], len(y))
+                axes.addpline(noiseline, y, idline=1, color="black", linestyle="dashed", lw=2)
             
         self.draw()
         
diff --git a/schainpy/model/jroprocessing.py b/schainpy/model/jroprocessing.py
index 631392d..9d1dd6a 100644
--- a/schainpy/model/jroprocessing.py
+++ b/schainpy/model/jroprocessing.py
@@ -216,6 +216,7 @@ class VoltageProc(ProcessingUnit):
         
         self.objectDict = {}
         self.dataOut = Voltage()
+        self.flip = 1
 
     def init(self):
         
@@ -362,6 +363,9 @@ class VoltageProc(ProcessingUnit):
         self.dataOut.data = buffer
         self.dataOut.heightList = numpy.arange(self.dataOut.heightList[0],newdelta*self.dataOut.nHeights/window-newdelta,newdelta)
 
+    def deFlip(self):
+        self.dataOut.data *= self.flip
+        self.flip *= -1.
 
 
 class CohInt(Operation):