def aliases_figure(f0, fs):
t = np.linspace(0, 1, 50*fs)
y = np.sin(f0 * 2*np.pi * t)
sig = Signal(t, y)
alias_sig = Signal(t, y)
fig = sig.get_fig(size=(1080,300),title="Aliases of {} Hz signal".format(f0))
alias_sig.update_line_opts({'line_color' : 'orange', 'line_alpha': 1})
alias_sig.create_line_renderer(fig)
alias_x = np.linspace(0, 1, fs, endpoint=False)
alias_y = np.sin(f0 * 2*np.pi * alias_x)
alias_points = ColumnDataSource({
'x' : alias_x,
'y' : alias_y,
'y0': np.zeros(alias_x.size)
})
fig.circle(x='x', y='y', source=alias_points, fill_color='red', line_width=3, line_color='red')
fig.segment(x0='x', x1='x', y0='y0', y1='y', source=alias_points,line_width=3, line_color='red')
handle = show(fig, notebook_handle=True)
def frame_gen(fv):
return {'y': np.sin(fv*2*np.pi*t)}
anim_sets = []
for k in range(1, 6):
f_previous = f0 + (k-1)*fs
f_alias = f0 + k*fs
frame_values = np.linspace(f_previous, f_alias, 60)
anim = FrameAnimation(alias_sig.data_source(), frame_gen, frame_values)
anim_sets.append(AnimationSet([anim]))
anim_sets.append(AnimationSet([Pause(1)]))
AnimateSets(anim_sets, handle).run()
