code: def export_to_fta(self, sample_rate, filename: str, include_amplitude=False):
          
          spectrogram = self.__calculate_spectrogram(self.samples)
          spectrogram = np.flipud(spectrogram.T)
          if include_amplitude:
              result = np.empty((spectrogram.shape[0], spectrogram.shape[1], 3),
                                dtype=[('f', np.float64), ('t', np.uint32), ('a', np.float32)])
          else:
              result = np.empty((spectrogram.shape[0], spectrogram.shape[1], 2),
                                dtype=[('f', np.float64), ('t', np.uint32)])
  
          fft_freqs = np.fft.fftshift(np.fft.fftfreq(spectrogram.shape[0], 1/sample_rate))
          time_width = 1e9 * ((len(self.samples) / sample_rate) / spectrogram.shape[1])
  
          for i in range(spectrogram.shape[0]):
              for j in range(spectrogram.shape[1]):
                  if include_amplitude:
                      result[i, j] = (fft_freqs[i], int(j*time_width), spectrogram[i, j])
                  else:
                      result[i, j] = (fft_freqs[i], int(j * time_width))
  
          result.tofile(filename)
docs: Export to Frequency, Time, Amplitude file.
          Frequency is double, Time (nanosecond) is uint32, Amplitude is float32
  
          :return: