new frequency primitive

sigpro/transformations/amplitude/fftfreq.py

@@ -0,0 +1,23 @@
+"""Build power spectrum from amplitude values."""
+
+
+import numpy as np
+
+
+def fft_freq(amplitude_values, sampling_frequency):
+    """Compute the Frequency having FFT values
+
+    Args:
+        amplitude_values (np.ndarray):
+            A numpy array with the signal values.
+        sampling_frequency (int or float):
+            Sampling frequency value passed in Hz.
+    Returns:
+        tuple:
+            * `amplitude_values (numpy.ndarray)`
+            * `frequency_values (numpy.ndarray)`
+    """
+    amplitude_values = amplitude_values
+    frequency_values = np.fft.fftfreq(len(amplitude_values), 1 / sampling_frequency)
+
+    return amplitude_values, frequency_values