def get_stability_notes(h):
from app_math import find_first_zero_idx
from iir_models import correct_pfc
""" По Найквесту """
# Сперва запас по фазе
cut_position = find_first_zero_idx(to_dB(abs(h)))
rest_phase = 180-abs(angle(h[cut_position])*180/pi)
# По амплитуде
phases_rad = correct_pfc(h)
ampl_idx = find_first_zero_idx(phases_rad+pi)
ampl = abs(h[ampl_idx])
return rest_phase, ampl
def calc_analog_filter_curves(params, freq_axis, af_action):
total_samples = len(freq_axis)
w_complex = 1j*2*pi*freq_axis
h, phi, h_complex = calc_afc(w_complex, params, af_action), \
calc_pfc(w_complex, params, af_action), calc_complex_h(w_complex, params, af_action)
# Нужно подправить ФЧХ
phi_copy = arange(total_samples)
adder = 0
for i in range(total_samples-1):
if abs(phi[i]-phi[i+1]) > 180:
adder += abs(phi[i]-phi[i+1])
phi_copy[i+1] = phi[i+1]-adder
return (h, phi_copy, freq_axis, to_dB(h), h_complex)
def plot_normalize_analog(h, phi, freq_axis, freq_sampling, cut_position):
# Abs
y_dB = to_dB(h)
subplot(2, 1, 1)
ylabel('20*log(K)')
xlabel('F, Hz')
grid()
axis = freq_axis/freq_sampling
plot(axis, y_dB)
plot(freq_axis[cut_position]/freq_sampling, y_dB[cut_position], 'o')
xlim(0, freq_sampling/2/freq_sampling)
# Angle
subplot(2, 1, 2)
grid()
ylabel('Phase, deg')
xlabel('F, Hz')
plot(axis, phi)
plot(freq_axis[cut_position]/freq_sampling, phi[cut_position], 'o')
xlim(0, freq_sampling/2/freq_sampling)
def _plotter_angle_and_abs(h, w):
h_dB = to_dB(abs(h))
f_axis = w/2/pi
# Plot
subplot(211)
plot(f_axis, h_dB)
#ylim(min(h_dB), max(h_dB))
#xlim(0, max(f_axis))
ylabel('Magnitude (db)')
xlabel(r'Normalized Frequency (x$\pi$rad/sample)')
title(r'Frequency response')
# Plot
subplot(212)
h_Phase = unwrap(arctan2(imag(h),real(h)))*180/pi
plot(f_axis,h_Phase)
xlim(0, max(f_axis))
ylabel('Phase (radians)')
xlabel(r'Normalized Frequency (x$\pi$rad/sample)')
title(r'Phase response')
subplots_adjust(hspace=0.5)