# test of biquad filter
import numpy as np
from BiquadFilter import BiquadFilter
import matplotlib.pyplot as plt

omega = 10
q = 2
dt = 0.01

tflow = BiquadFilter(omega, q, dt, "lowpass")
tfhigh = BiquadFilter(omega, q, dt, "highpass")
tfband = BiquadFilter(omega, q, dt, "bandpass")
tfnotch = BiquadFilter(omega, q, dt, "notch")

tflow.PrintContinuousTF(); print('')
tfhigh.PrintContinuousTF(); print('')
tfband.PrintContinuousTF(); print('')
tfnotch.PrintContinuousTF(); print('')

# simulate filter response
tend = 10
Npts = int(np.ceil(tend/dt))
Yl = np.zeros(Npts)
Yh = np.zeros(Npts)
Yband = np.zeros(Npts)
Ynotch = np.zeros(Npts)
T = np.zeros(Npts)

for i in range(Npts):
    t = i*dt
    if t >= 1:
        x = 1
    else:
        x = 0

    T[i] = t
    Yl[i] = tflow.Filter(x)
    Yh[i] = tfhigh.Filter(x)
    Yband[i] = tfband.Filter(x)
    Ynotch[i] = tfnotch.Filter(x)

plt.plot(T, Yl, T, Yh, T, Yband, T, Ynotch)
plt.grid(True)
plt.show()