use *.wav format for demodulated signal export

Author: jopohl

src/urh/controller/widgets/SignalFrame.py

@@ -456,12 +456,12 @@ def save_signal_as(self):
 
     def export_demodulated(self):
         try:
-            initial_name = self.signal.name + "-demodulated.complex"
+            initial_name = self.signal.name + "-demodulated.wav"
         except Exception as e:
             logger.exception(e)
-            initial_name = "demodulated.complex"
+            initial_name = "demodulated.wav"
 
-        filename = FileOperator.ask_save_file_name(initial_name)
+        filename = FileOperator.ask_save_file_name(initial_name, caption="Export demodulated")
         if filename:
             try:
                 self.setCursor(Qt.WaitCursor)

src/urh/util/FileOperator.py

@@ -94,6 +94,8 @@ def ask_save_file_name(initial_name: str, caption="Save signal", selected_name_f
         name_filter = "Frequency Time (*.ft);;Frequency Time Amplitude (*.fta)"
     elif caption == "Save protocol":
         name_filter = ";;".join([PROTOCOL_FILE_FILTER, BINARY_PROTOCOL_FILE_FILTER])
+    elif caption == "Export demodulated":
+        name_filter = WAV_FILE_FILTER
     else:
         name_filter = EVERYTHING_FILE_FILTER