Implement frequency filters

double_text_button.py

@@ -0,0 +1,16 @@
+from PyQt5.QtWidgets import QPushButton
+
+class DoubleTextButton(QPushButton):
+    def __init__(self, parent = None):
+        super().__init__(parent)
+        self.clicked.connect(self.change_text)
+
+    def set_texts(self, text_a, text_b):
+        self.text_a = text_a
+        self.text_b = text_b
+
+    def change_text(self):
+        if self.isChecked():
+            self.setText(self.text_b)
+        else:
+            self.setText(self.text_a)