diff --git a/dmi.py b/dmi.py
index a3b9bea..070e239 100644
--- a/dmi.py
+++ b/dmi.py
@@ -14,7 +14,7 @@ def main():
     freq_base = 1088230e3
     block_size = 4096
 
-    gui = GUI(block_size)
+    gui = GUI(freq_sample, freq_base, block_size)
     try:
         induction = InductionHeater("/dev/ttyUSB0", 350e3, 445e3)
         induction.start()
diff --git a/gui.py b/gui.py
index 9366dd3..ba20399 100644
--- a/gui.py
+++ b/gui.py
@@ -48,11 +48,11 @@ class ParentComm:
 
 
 class GUI:
-    def __init__(self, block_size):
+    def __init__(self, freq_sample, freq_base, block_size):
         self.impl = ParentComm()
         self.impl.create_subprocess([sys.executable,
                                      os.path.join(os.path.dirname(os.path.abspath(__file__)), "gui_impl.py"),
-                                     str(block_size)])
+                                     str(freq_sample), str(freq_base), str(block_size)])
 
     def update_beat_spectrum(self, data):
         obj = {"action": "update_beat_spectrum", "data": data}
diff --git a/gui_impl.py b/gui_impl.py
index b29296b..ad045f1 100644
--- a/gui_impl.py
+++ b/gui_impl.py
@@ -4,32 +4,31 @@ import sys
 import logging
 
 import numpy as np
-from quamash import QEventLoop, QtWidgets
+from quamash import QEventLoop, QtWidgets, QtCore
 import pyqtgraph as pg
 from sipyco.pipe_ipc import AsyncioChildComm
 from sipyco import pyon
  
 
 class SpectrogramWidget(pg.PlotWidget):
-    def __init__(self, block_size):
+    def __init__(self, freq_sample, freq_base, block_size):
         super(SpectrogramWidget, self).__init__()
- 
-        self.block_size = block_size
- 
+
+        depth = 100
+        self.img_array = np.zeros((depth, block_size))
+
         self.img = pg.ImageItem()
         self.addItem(self.img)
- 
-        self.img_array = np.zeros((100, block_size))
+
+        self.img.setImage(self.img_array, autoLevels=True)
  
         pos = np.array([0., 1., 0.5, 0.25, 0.75])
         color = np.array([[0,255,255,255], [255,255,0,255], [0,0,0,255], (0, 0, 255, 255), (255, 0, 0, 255)], dtype=np.ubyte)
         cmap = pg.ColorMap(pos, color)
         lut = cmap.getLookupTable(0.0, 1.0, 256)
- 
         self.img.setLookupTable(lut)
-        self.img.setLevels([-50,40])
-  
-        self.show()
+
+        self.img.setRect(QtCore.QRectF(0.0, freq_base-freq_sample/2, float(depth), freq_sample))
 
     def update(self, block):
         self.img_array = np.roll(self.img_array, -1, 0)
@@ -62,7 +61,9 @@ class IPCClient(AsyncioChildComm):
 
 
 def main():
-    block_size = int(sys.argv[1])
+    freq_sample = float(sys.argv[1])
+    freq_base = float(sys.argv[2])
+    block_size = int(sys.argv[3])
 
     app = QtWidgets.QApplication([])
     loop = QEventLoop(app)
@@ -72,7 +73,8 @@ def main():
         ipc = IPCClient(os.getenv("NOPTICA2_IPC"))
         loop.run_until_complete(ipc.connect())
         try:
-            main_widget = SpectrogramWidget(block_size)
+            main_widget = SpectrogramWidget(freq_sample, freq_base, block_size)
+            main_widget.setWindowTitle("NOPTICA Wavemeter")
             main_widget.show()
             ipc.set_close_cb(main_widget.close)
             asyncio.ensure_future(ipc.listen(main_widget))