process_data returns frequency series

tupak/detector.py

@@ -366,7 +366,7 @@ class Interferometer(object):
             logging.info('Reading data from frame, {}.'.format(self.name))
             strain = tupak.utils.read_frame_file(frame_file, t1=epoch, t2=epoch+duration, channel=channel_name,
                                                  resample=sampling_frequency)
-            frequency_domain_strain = tupak.utils.process_strain_data(strain, **kwargs)
+            frequency_domain_strain, frequencies = tupak.utils.process_strain_data(strain, **kwargs)
             frequencies = utils.create_frequency_series(sampling_frequency, duration)
             self.power_spectral_density = PowerSpectralDensity(frame_file=frame_file, channel_name=channel_name,
                                                                **kwargs)

tupak/utils.py

@@ -617,9 +617,9 @@ def process_strain_data(
     N = len(time_series)
     strain = strain * signal.windows.tukey(N, alpha=alpha)
 
-    frequency_domain_strain = nfft(strain.value, sampling_frequency)[0]
+    frequency_domain_strain, frequencies = nfft(strain.value, sampling_frequency)
 
-    return frequency_domain_strain
+    return frequency_domain_strain, frequencies
 
 
 def set_up_command_line_arguments():