get power line frequency value

Author: salman2135

src/explorepy/explore.py

@@ -182,13 +182,15 @@ def record_data(
         if file_type not in ['edf', 'csv']:
             raise ValueError(
                 '{} is not a supported file extension!'.format(file_type))
+
         if imp_mode:
+            if not self.stream_processor.is_imp_running():
+                raise ValueError('Impedance measurement not running!')
             if file_type == 'edf':
                 raise ValueError(
                     '{} is not a supported file extension for recording impedance!'.format(file_type))
-            if notch_freq is None:
-                raise ValueError(
-                    'Missing notch frequency argument, please provide the notch frequency to get live impedance values')
+
+            notch_freq = self.stream_processor.get_power_line_freq() or 50
 
         duration = self._check_duration(duration)
 

src/explorepy/filters.py

@@ -31,6 +31,7 @@ def __init__(self, cutoff_freq, filter_type, s_rate, n_chan, order=5):
         self.s_rate = float(s_rate)
         self.filter_type = filter_type
         self.filter_param = None
+        self.cutoff_freq = cutoff_freq
         order = 2 if self.s_rate > 1000 else order
         a, b, zi = self.get_filter_coeffs(cutoff_freq, filter_type, s_rate, n_chan, order)
         self.filter_param = {'a': a, 'b': b, 'zi': zi}
@@ -110,6 +111,9 @@ def get_notch_coeffs(cutoff, nyquist, n_channels, order, quality=30, imp_mode=Fa
             zi = np.zeros(shape=(n_channels, 2))
         return a, b, zi
 
+    def get_cutoff_freq(self):
+        return self.cutoff_freq
+
     def apply(self, input_data, in_place=True):
         """Apply filter
 

src/explorepy/stream_processor.py

@@ -314,7 +314,7 @@ def process(self, packet):
             missing_timestamps = self.fill_missing_packet(packet)
             self._update_last_time_point(packet, received_time)
             self.packet_count += 1
-            if self._is_imp_mode and self.imp_calculator:
+            if self.is_imp_running():
                 packet_imp = self.imp_calculator.measure_imp(
                     packet=copy.deepcopy(packet))
                 if packet_imp is not None:
@@ -459,9 +459,10 @@ def imp_initialize(self, notch_freq, calibration=False):
         cmd = ZMeasurementEnable()
         if self.configure_device(cmd):
             self.imp_calib_info['calibration'] = calibration
+            self._add_notch_filter()
             self.imp_calculator = ImpedanceMeasurement(device_info=self.device_info,
                                                        calib_param=self.imp_calib_info,
-                                                       notch_freq=notch_freq)
+                                                       notch_freq=self.get_power_line_freq())
             self._is_imp_mode = True
         else:
             raise ConnectionError('Device configuration process failed!')
@@ -475,6 +476,7 @@ def disable_imp(self):
             return True
         print("WARNING: Couldn't disable impedance measurement mode. "
               "Please restart your device manually.")
+        self._notch_filter = None
         return False
 
     def set_marker(self, marker_string, time_lsl=None, name='mkr', soft_marker=True):
@@ -596,3 +598,14 @@ def _add_notch_filter(self):
             s_rate=250,
             n_chan=SettingsManager(self.device_info['device_name']).get_channel_count()
         )
+
+    def is_imp_running(self):
+        return self._is_imp_mode and self.imp_calculator
+
+    def get_power_line_freq(self):
+        match = next(
+            (item for item in self.filters if item.filter_type == 'notch'),
+            None
+        )
+
+        return match.cutoff_freq if match else None