#!/usr/bin/python3
import numpy as np
from lasp import SeriesBiquad, AvPowerSpectra
from lasp.filter import SPLFilterDesigner
import matplotlib.pyplot as plt
from scipy.signal import sosfreqz
plt.close('all')

fs = 48000
omg = 2*np.pi*1000

filt = SPLFilterDesigner(fs).A_Sos_design()

bq = SeriesBiquad(filt.flatten())

tend=10
t = np.linspace(0, int((tend*fs)//fs), int(tend*fs), endpoint=False)

in_ = np.random.randn(t.size)
out = bq.filter(in_)


from scipy.signal import welch
nfft = 48000
freq, H1 = welch(out, 
                # scaling 
                fs=fs,nfft=nfft)

freq, H2 = welch(in_, 
                # scaling 
                fs=fs,nfft=nfft)
# plt.figure()
plt.semilogx(freq,10*np.log10(np.abs(H1/H2)))

omg, H_ex = sosfreqz(filt)
plt.semilogx(omg/(2*np.pi)*fs, 20*np.log10(np.abs(H_ex)+1e-80))