display detected beat frequency

dmi.py

@@ -19,8 +19,8 @@ def main():
         induction = InductionHeater("/dev/ttyUSB0", 350e3, 445e3)
         induction.start()
         try:
-            def stabilizer_cb(spectrum, tuning):
-                gui.update_beat_spectrum(spectrum)
+            def stabilizer_cb(spectrum, peak_freq, tuning):
+                gui.update_beat_spectrum(spectrum, peak_freq)
                 induction.set(tuning)
 
             stabilizer = Stabilizer(block_size, 80.0, 1088.1e6 - freq_base, 10e-6, stabilizer_cb)

gui.py

@@ -54,8 +54,8 @@ class GUI:
                                      os.path.join(os.path.dirname(os.path.abspath(__file__)), "gui_impl.py"),
                                      str(freq_sample), str(freq_base), str(block_size)])
 
-    def update_beat_spectrum(self, data):
-        obj = {"action": "update_beat_spectrum", "data": data}
+    def update_beat_spectrum(self, block, peak_freq):
+        obj = {"action": "update_beat_spectrum", "block": block, "peak_freq": peak_freq}
         self.impl.write_pyon(obj)
 
     def close(self):

gui_impl.py

@@ -10,30 +10,49 @@ from sipyco.pipe_ipc import AsyncioChildComm
 from sipyco import pyon
  
 
-class SpectrogramWidget(pg.PlotWidget):
+class SpectrogramItem(pg.ImageItem):
     def __init__(self, freq_sample, freq_base, block_size):
-        super(SpectrogramWidget, self).__init__()
+        pg.ImageItem.__init__(self)
 
         depth = 100
         self.img_array = np.zeros((depth, block_size))
 
-        self.img = pg.ImageItem()
-        self.addItem(self.img)
-
-        self.img.setImage(self.img_array, autoLevels=True)
+        self.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.setLookupTable(lut)
 
-        self.img.setRect(QtCore.QRectF(0.0, freq_base-freq_sample/2, float(depth), freq_sample))
+        self.setRect(QtCore.QRectF(0.0, (freq_base-freq_sample/2)/1e6, float(depth), freq_sample/1e6))
 
-    def update(self, block):
+    def add_block(self, block):
         self.img_array = np.roll(self.img_array, -1, 0)
         self.img_array[-1:] = np.fft.fftshift(block) 
-        self.img.setImage(self.img_array, autoLevels=True)
+        self.setImage(self.img_array, autoLevels=True)
+
+
+class MainWindow(pg.GraphicsWindow):
+    def __init__(self, freq_sample, freq_base, block_size):
+        pg.GraphicsWindow.__init__(self)
+        self.setWindowTitle("NOPTICA Wavemeter")
+
+        self.freq_sample = freq_sample
+        self.freq_base = freq_base
+
+        self.text = pg.LabelItem()
+        self.addItem(self.text)
+
+        p1 = self.addPlot(row=1, col=0)
+        self.beat_spectrum = SpectrogramItem(freq_sample, freq_base, block_size)
+        p1.addItem(self.beat_spectrum)
+
+    def update_params(self, peak_freq):
+        if peak_freq is None:
+            self.text.setText("REF: NO BEAT")
+        else:
+            self.text.setText("REF: {:.3f}MHz".format((self.freq_base + self.freq_sample*peak_freq)/1e6))
 
 
 class IPCClient(AsyncioChildComm):
@@ -44,13 +63,14 @@ class IPCClient(AsyncioChildComm):
         line = await self.readline()
         return pyon.decode(line.decode())
 
-    async def listen(self, spectrogram):
+    async def listen(self, main_window):
         while True:
             obj = await self.read_pyon()
             try:
                 action = obj["action"]
                 if action == "update_beat_spectrum":
-                    spectrogram.update(obj["data"])
+                    main_window.beat_spectrum.add_block(obj["block"])
+                    main_window.update_params(obj["peak_freq"])
                 if action == "terminate":
                     self.close_cb()
                     return
@@ -73,11 +93,10 @@ def main():
         ipc = IPCClient(os.getenv("NOPTICA2_IPC"))
         loop.run_until_complete(ipc.connect())
         try:
-            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))
+            main_window = MainWindow(freq_sample, freq_base, block_size)
+            main_window.show()
+            ipc.set_close_cb(main_window.close)
+            asyncio.ensure_future(ipc.listen(main_window))
             loop.run_forever()
         finally:
             ipc.close()

noptica.py

@@ -116,14 +116,15 @@ class Stabilizer:
     def input(self, samples):
         spectrum = np.abs(np.fft.fft(samples*blackmanharris(len(samples))))
         i = np.argmax(spectrum)
-        freq = self.freqs[i]
         amplitude = spectrum[i]
 
         if amplitude > self.amp_threshold:
+            freq = self.freqs[i]
             tuning = (freq - self.freq_target)*self.k
         else:
+            freq = None
             tuning = 0.0
-        self.cb(spectrum, tuning)
+        self.cb(spectrum, freq, tuning)
 
 
 def continuous_unwrap(last_phase, last_phase_unwrapped, p):