import pyfar as pf
signal = pf.signals.sine(1e3, 4410)
signal.fft_norm = "amplitude"
smoothed, _ = pf.dsp.smooth_fractional_octave(signal, 1)
ax = pf.plot.freq(signal, label="input")
pf.plot.freq(smoothed, label="smoothed")
ax.set_xlim(200, 4e3)
ax.set_ylim(-45, 5)
ax.legend(loc=3)