def chuck(samplerate, sig, shift_hz=1000):
rc_imag = [
allpass(samplerate, rc)
for rc in [5.49e-06, 4.75e-05, 2.37e-04, 1.27e-03]
]
rc_real = [
allpass(samplerate, rc)
for rc in [2.00e-05, 1.07e-04, 5.36e-04, 4.64e-03]
]
sos_imag = [
signal.tf2sos(
polynomial.polymul(rc1[0], rc2[0]),
polynomial.polymul(rc1[1], rc2[1]),
)[0] for rc1, rc2 in zip(rc_imag[::2], rc_imag[1::2])
]
sos_real = [
signal.tf2sos(
polynomial.polymul(rc1[0], rc2[0]),
polynomial.polymul(rc1[1], rc2[1]),
)[0] for rc1, rc2 in zip(rc_real[::2], rc_real[1::2])
]
# plot_response(sys._getframe().f_code.co_name, sos_real, sos_imag)
real = signal.sosfilt(sos_real, sig)
imag = signal.sosfilt(sos_imag, sig)
analytic = 0.5 * (real - 1j * imag)
return pitch_shift(samplerate, analytic, shift_hz)
def group_delays(b, a, w, plot=None):
"""
Compute group delay of analog filter.
Parameters
----------
b : array_like
Numerator of a linear filter.
a : array_like
Denominator of a linear filter.
w : array_like
Angular frequencies in rad/s.
plot : callable, optional
A callable that takes two arguments. If given, the return parameters
`w` and `gd` are passed to plot.
Returns
-------
w : ndarray
The angular frequencies at which `gd` was computed.
gd : ndarray
The group delay in seconds.
"""
b, a = map(np.atleast_1d, (b, a))
sos = tf2sos(b, a)
gd = sos_group_delays(sos, w)[1]
if plot is not None:
plot(w, gd)
return w, gd
def low_pass_filter(signal, fs, end_freq):
"""
Description
- Low Pass Filter
Input
:param signal:list, 입력 신호
:param fs: Float, 샘플링 주파수 (sampling frequency)
:param end_freq: Float, 끝 주파수 (passband)
Output
:return list, 필터링된 신호
Example:
>>> signal = [0, 1, 2, 3, 2, 1, 0, -1, -2, -3, -2, -1]
>>> fs = 0.1
>>> end_freq = 0.02
>>> low_pass_filter(signal, fs, end_freq)
array([-7.04764275e-05, 1.06577490e+00, 2.14355722e+00, 2.64998306e+00,
2.14375040e+00, 1.06552842e+00, -1.00019323e-03, -1.06409485e+00,
-2.13795954e+00, -2.66057414e+00, -2.17495858e+00, -9.99904965e-01])
"""
n, wn = buttord(2 * end_freq / fs, 4 * end_freq / fs, 1, 10) # 'Butterworth Filter'의 차수(order) 구하기
b, a = butter(n, wn, btype='low') # 'Butterworth Filter'의 a와 b 파라메터 생성
sos = tf2sos(b, a) # 2차수(order) 필터 계수의 배열 구하기
signal = np.array(signal).reshape(-1) # 1차원 리스트가 아닌 경우를 위해 1차원으로 변환
filtered_signal = sosfiltfilt(sos, signal) # A forward-backward digital filter using cascaded second-order sections.
return filtered_signal
def design_filter(self):
"""
This filter is used to design Biquad Filters
This creates the A and B coefficients for Biquad IIR filters as used in CSPL
"""
f0 = self.fc.value()
Q = self.Q.value()
gain = self.linear_gain.value()
biquadType = self.filter_type.value()
design_function = BIQUAD_DESIGN_LIBRARY[biquadType]
b_coefficients, a_coefficients = design_function(
gain, f0, Q, SAMPLERATE)
# if the filter design results in a numerator and denominator that are equal, then just implement the passthrough filter
if np.array_equal(b_coefficients, a_coefficients):
b_coefficients = np.array([1., 0., 0.])
a_coefficients = np.array([1., 0., 0.])
self.a = np.array(a_coefficients) / a_coefficients[0]
self.b = np.array(b_coefficients) / a_coefficients[0]
assert len(self.a) == 3
assert len(self.b) == 3
self.sos = signal.tf2sos(self.b, self.a)
self.coefficients_changed.emit()
def low_shelving_2nd_cascade(w0,
Gb,
num_biquad,
biquad_per_octave,
Q=1 / np.sqrt(2)):
"""Low shelving filter design using cascaded biquad filters.
Parameters
----------
w0 : float
Cut-off frequency in radian per second.
Gb : float
Gain of each biquad filter in decibel.
num_biquad : int
Number of biquad filters.
Q : float, optional
Quality factor of each biquad filter.
Returns
-------
sos : array_like
Array of second-order filter coefficients, must have shape
``(n_sections, 6)``. Each row corresponds to a second-order
section, with the first three columns providing the numerator
coefficients and the last three providing the denominator
coefficients.
"""
sos = np.zeros((num_biquad, 6))
for m in range(num_biquad):
wm = w0 * 2**(-(m + 0.5) / biquad_per_octave)
b, a = low_shelving_2nd_coeff(omega=wm, G=Gb, Q=Q)
sos[m] = tf2sos(b, a)
return sos
def group_delayz(b, a, w, plot=None, fs=2*np.pi):
"""
Compute the group delay of digital filter.
Parameters
----------
b : array_like
Numerator of a linear filter.
a : array_like
Denominator of a linear filter.
w : array_like
Frequencies in the same units as `fs`.
plot : callable
A callable that takes two arguments. If given, the return parameters
`w` and `gd` are passed to plot.
fs : float, optional
The angular sampling frequency of the digital system.
Returns
-------
w : ndarray
The frequencies at which `gd` was computed, in the same units as `fs`.
gd : ndarray
The group delay in seconds.
"""
b, a = map(np.atleast_1d, (b, a))
if len(a) == 1:
# scipy.signal.group_delay returns gd in samples thus scaled by 1/fs
gd = sig.group_delay((b, a), w=w, fs=fs)[1]
else:
sos = sig.tf2sos(b, a)
gd = sos_group_delayz(sos, w, plot, fs)[1]
if plot is not None:
plot(w, gd)
return w, gd
def __init__(self, output_count, dtype, color):
"""
Parameters
----------
output_count : int
number of channels to generate
dtype : str or numpy.dtype or type
data type to generate
color : str
coloration of noise to generate
"""
super().__init__(output_count=output_count, dtype=dtype)
color = color.upper()
# initialize constants
self._GAIN_FACTOR = 20
# fmt: off
self._B_PINK = np.array([0.049922035, -0.095993537, 0.050612699, -0.004408786], dtype=dtype)
self._A_PINK = np.array([1, -2.494956002, 2.017265875, -0.522189400], dtype=dtype)
# "Consider designing filters in ZPK format and converting directly to SOS."
# https://docs.scipy.org/doc/scipy/reference/generated/scipy.signal.tf2sos.html
self._SOS_EM = np.array(
[[0.0248484318401191, -0.0430465879719351, 0.0185894592446002, 1, -1.83308400613427,
0.833084457582538],
[1.09742855358091, -2, 0.902572344822294, 1, -1.84861597668780, 0.849007279800584],
[1.32049919002049, -2, 1.27062183754708, 1, -1.51266987481441, 0.958710654962438],
[2, -1.23789744854974, 0.693137522016399, 1, -0.555672516031578, 0.356572277622976],
[2, -0.127412449936323, 0.451198075878658, 1, -0.0464446484127454, 0.0651312831643292],
[0.295094951044653, 0.0954033015853709, 0, 1, 0, 0]],
dtype=dtype
)
# fmt: on
# pick utilized coefficients
if color == "PINK":
a = self._A_PINK
self._sos = tf2sos(b=self._B_PINK, a=self._A_PINK).astype(dtype)
# "It is generally discouraged to convert from TF to SOS format, since doing so
# usually will not improve numerical precision errors."
# https://docs.scipy.org/doc/scipy/reference/generated/scipy.signal.tf2sos.html
elif color in ["EM", "EIGENMIKE"]:
[_, a] = sos2tf(sos=self._SOS_EM)
self._sos = self._SOS_EM
else:
raise NotImplementedError(
f'chosen noise generator color "{color}" not implemented yet.'
)
# initialize IIR filter delay conditions
self._last_delays = sosfilt_zi(sos=self._sos).astype(dtype)
# adjust in middle axis according to output count
self._last_delays = np.repeat(
self._last_delays[:, np.newaxis, :], repeats=output_count, axis=1
)
# approximate decay time to skip transient response part of IIR filter, according to [1]
t60_samples = int(np.log(1000.0) / (1.0 - np.abs(np.roots(a)).max())) + 1
# generate and discard long enough sequence to skip IIR transient response (decay time)
_ = self.generate_block(block_length=t60_samples)
def reconstruction(self, v):
out = np.zeros(v.shape[0])
for index, filter in enumerate(self.H):
print("For filter %i, with coefficents\n%s\n" % (index, filter))
sos = signal.tf2sos(filter.num, filter.den)
noise = signal.sosfilt(sos, v[:, index])
out = out + (-1.)**(index) * noise
return out
def __init__(self,
name,
input_signal,
b=[1., 1.],
a=[1., 1., 1.],
**kwargs):
super().__init__(name, **kwargs)
self._input = input_signal
self._sos = sp.tf2sos(b, a)
def applyThiran(sig, order=12, oversample=8):
out = []
for fraction in np.linspace(0, 1, oversample, endpoint=False)[1:]:
b, a = thiranAllpass(order, fraction)
sos = signal.tf2sos(b, a)
out.append(signal.sosfilt(sos, sig))
delay = order // 2
index = np.linspace(-delay, len(sig) - delay, len(out), endpoint=False)
return out, index
def design_filter(self):
R = self.R.value()
Rleak = self.Rleak.value()
L = self.L.value()
Zs = signal.lti([(R + Rleak) * L, R * Rleak], [L, Rleak])
Zd = Zs.to_discrete(1 / SAMPLERATE)
self.b = Zd.num
self.a = Zd.den
self.sos = signal.tf2sos(self.b, self.a)
self.coefficients_changed.emit()
def mcnulty(samplerate, sig, shift_hz=1000):
rc_real = [
allpass(samplerate, rc) for rc in [
9.31e-06,
4.2723e-05,
0.0001836,
0.00078146,
0.003333,
0.026055,
]
]
rc_imag = [
allpass(samplerate, rc) for rc in [
2.6676e-06,
2.08e-05,
8.87e-05,
0.00038064,
0.0016049999999999999,
0.007412,
]
]
sos_real = [
signal.tf2sos(
polynomial.polymul(rc1[0], rc2[0]),
polynomial.polymul(rc1[1], rc2[1]),
)[0] for rc1, rc2 in zip(rc_real[::2], rc_real[1::2])
]
sos_imag = [
signal.tf2sos(
polynomial.polymul(rc1[0], rc2[0]),
polynomial.polymul(rc1[1], rc2[1]),
)[0] for rc1, rc2 in zip(rc_imag[::2], rc_imag[1::2])
]
# plot_response(sys._getframe().f_code.co_name, sos_real, sos_imag)
real = signal.sosfilt(sos_real, sig)
imag = signal.sosfilt(sos_imag, sig)
analytic = 0.5 * (real - 1j * imag)
return pitch_shift(samplerate, analytic, shift_hz)
def receive_stages(self, b, a):
self.sos = np.array(ss.tf2sos(b, a, pairing='keep_odd'))
for it in range(0, len(self.sos)):
self.stages_list.append(False)
tempObject = stageControl(self, self.stages_list, it)
tempItem = QtWidgets.QListWidgetItem()
tempItem.setSizeHint(tempObject.sizeHint())
self.ui.FilterList.addItem(tempItem)
self.ui.FilterList.setItemWidget(tempItem, tempObject)
self.manage_plot() #Ploteamos las etapas
def make_digital_filter(N, rp, rs, Wn, btype='low'):
finish = False
WnAdd = Wn
rpAdd = rp
rsAdd = rs
fullArray = []
try:
while (finish == False):
if (WnAdd < 0.5):
WnAdd = WnAdd + 0.001
elif (abs(rpAdd - rp) / rp < 0.05):
rpAdd = rpAdd + 0.01
elif (abs(rsAdd - rs) / rs < 0.05):
rsAdd = rsAdd + 0.01
else:
raise Exception(
"There is no filters with these characteristics.")
b, a = signal.ellip(N, rpAdd, rsAdd, WnAdd, btype, analog=False)
sos = signal.tf2sos(b, a)
#print sos
w, h = signal.sosfreqz(sos, worN=1000000)
#plot_2nd_order_from_sos(sos)
makeCallibration(sos)
#plot_2nd_order_from_sos(sos)
#print "sos"
print sos
w, h = signal.sosfreqz(sos, worN=1000000)
#plot_sosfreqz(w,h)
#fullArray = getCoefficientsForElliptic(sos, True)
fullArray = getCoefficients(sos)
#print fullArray
try:
new_sos = getSosFromCoefficients(fullArray)
#new_sos = getSosFromCoefficientsForElliptic(fullArray)
finish = True
except ValueError as e:
pass
except Exception as e:
print e
print "There is no filters with these characteristics."
return
w, h = signal.sosfreqz(sos, worN=1000000)
#plot_sosfreqz(w,h)
print "new_sos"
print new_sos
print "general_coefficients"
fullArrayRounded = getRoundCoefficients(fullArray)
getKeysFromKoefArray(fullArrayRounded)
w, h = signal.sosfreqz(new_sos, worN=1000000)
plot_sosfreqz(w, h)
def high_shelving_1st_cascade(w0, Gb, num_biquad, biquad_per_octave):
"""High shelving filter design using cascaded biquad filters.
- see low_shelving_2nd_cascade()
- under construction for code improvement
"""
sos = np.zeros((num_biquad, 6))
for m in range(num_biquad):
wm = w0 * 2**(-(m + 0.5) / biquad_per_octave)
b, a = high_shelving_1st_coeff(omega=wm, G=Gb)
sos[m] = tf2sos(b, a)
return sos
def _normalized_sos(coeff):
# Subfunction to re-normalize the coefficients of the incoming LPC (FIR) coefficients to unity based on the noise
# gain np.sqrt(np.sum(coeff**2))
impulse = np.zeros(129)
impulse[64] = 1
sos = signal.tf2sos(1, coeff)
filtsig1 = signal.sosfilt(sos, impulse)
lpc_noise_gain = np.sqrt(np.sum(filtsig1**2))
gainmatrix = np.ones([sos.shape[0], sos.shape[1]])
gainmatrix[0, 0] = 1 / lpc_noise_gain
soscoeff = sos * gainmatrix
return soscoeff
def convert2SOS(myFilter):
SOSarray = tf2sos(myFilter.num, myFilter.den)
SOSnumber,_ = SOSarray.shape
SOSoutput = np.empty(shape=(SOSnumber,3))
for index in range(SOSnumber):
SOSoutput[index][:] = SOSarray[index][3::]
if SOSoutput[index][2]==0:
SOSoutput[index] = np.roll(SOSoutput[index],1)
return SOSoutput
def testApply():
samplerate = 44100
duration = 1 # seconds
frequency = 100
time = np.linspace(0, duration, duration * samplerate)
phase = (frequency * time)
saw = signal.sawtooth(phase, 1.0)
coef = thiran(16, 16.5)
print(coef)
sos = signal.tf2sos(*coef)
sig = signal.sosfilt(sos, saw)
print(f"Converge?: {np.all(np.isfinite(sig))}")
soundfile.write("out.wav", sig, samplerate, subtype="FLOAT")
def lowShelf(w0, Q, A):
#Low Shelf
#H(s) = A * ((s^2 + sqrt(A)*s/Q + A) / (A*(s^2) + sqrt(A)*s/Q + 1)
COSW0 = math.cos(w0)
alpha = math.sin(w0) / (2 * Q)
b0 = A * ((A + 1) - (A - 1) * COSW0 + (2 * math.sqrt(A) * alpha))
b1 = 2 * A * ((A - 1) - ((A + 1) * COSW0))
b2 = A * ((A + 1) - (A - 1) * COSW0 - (2 * math.sqrt(A) * alpha))
a0 = (A + 1) + ((A - 1) * COSW0) + (2 * math.sqrt(A) * alpha)
a1 = -2 * ((A - 1) + ((A + 1) * COSW0))
a2 = (A + 1) + ((A - 1) * COSW0) - (2 * math.sqrt(A) * alpha)
num = [b0, b1, b2]
den = [a0, a1, a2]
sos = signal.tf2sos(num, den)
return sos
def bandpass(w0, Q):
#BPF using peak gain Q
#H(s) = s / (s^2 + s/q + 1)
COSW0 = math.cos(w0)
alpha = math.sin(w0) / (2 * Q)
b0 = Q * alpha #= SINW0/2
b1 = 0
b2 = -b0
a0 = a + alpha
a1 = -2 * COSW0
a2 = 1 - alpha
num = [b0, b1, b2]
den = [a0, a1, a2]
sos = signal.tf2sos(num, den)
return sos
def peaking(w0, Q, A):
#Peaking EQ, modeled from:
#H(s) = (s^2 + s*A/Q + 1) / ( s^2 + s/(A*Q) + 1)
COSW0 = math.cos(w0)
alpha = math.sin(w0) / (2 * Q)
b0 = 1 + (alpha * A)
b1 = -2 * COSW0
b2 = 1 - (alpha * A)
a0 = 1 + (alpha / A)
a1 = -2 * COSW0
a2 = 1 - (alpha / A)
num = [b0, b1, b2]
den = [a0, a1, a2]
sos = signal.tf2sos(num, den)
return sos
def highpass(w0, Q):
#HPF, modeled from:
#H(s) = (s^2) / ((s^2) + (s/Q) + 1)
COSW0 = math.cos(w0)
alpha = math.sin(w0) / (2 * Q)
b0 = (1 + COSW0) / 2
b1 = -(1 + COSW0)
b2 = b0
a0 = 1 + alpha
a1 = -2 * COSW0
a2 = 1 - alpha
num = [b0, b1, b2]
den = [a0, a1, a2]
sos = signal.tf2sos(num, den)
return sos
def get_session_encoding_models(session_info, models=None):
"""
Loops and computes traditional scores open-field scores for each unit, these include:
-> speed score: correlation between firing rate and speed
-> head angle score: correlation between firing rate and head angle
-> head directation score: correlation between firing rate and head direction
-> border score:
-> spatial information:
-> grid score:
:param SubjectSessionInfo session_info: instance of class SubjectInfo for a particular subject
:return: dict: with all the scores
"""
# get data
fr = session_info.get_fr()
# smooth data to match behavior time smoothness
sos_coefs = signal.tf2sos(session_info.task_params['filter_coef_'], 1)
fr2 = signal.sosfiltfilt(sos_coefs, fr, axis=1)
spikes = session_info.get_binned_spikes()
of_dat = SimpleNamespace(**session_info.get_track_data())
task_params = session_info.task_params
sem = spatial_funcs.AllSpatialEncodingModels(x=of_dat.x,
y=of_dat.y,
speed=of_dat.sp,
ha=of_dat.ha,
hd=of_dat.hd,
neural_data=fr2,
n_jobs=10,
**task_params)
if models is None:
sem.get_models()
else:
if isinstance(models, str):
models = [models]
for model in models:
model_method = f"get_{model}_model"
if hasattr(sem, model_method):
getattr(sem, model_method)()
else:
print(f"Encoding model for {model} does not exists.")
sem.get_scores()
return sem
def printSos(order=12, oversample=5):
for fraction in np.linspace(0, 1, oversample, endpoint=False)[1:]:
print(fraction)
b, a = thiran(order, order + fraction)
sos = signal.tf2sos(b, a)
print("{")
for section in sos:
text = " {"
for idx, value in enumerate(section):
if idx == 3:
continue
if idx != len(section) - 1:
text += f"Sample({value}), "
else:
text += f"Sample({value})"
print(text + "},")
print("}")
def lowShelf(w0, Q, A):
#WROTE AND TESTED THIS FUNCTION, LEFT IT UNUSED IN FINAL IMPLEMENTATION
#Low Shelf, modeled from:
#H(s) = A * ((s^2 + sqrt(A)*s/Q + A) / (A*(s^2) + sqrt(A)*s/Q + 1)
COSW0 = math.cos(w0)
alpha = math.sin(w0) / (2 * Q)
b0 = A * ((A + 1) - (A - 1) * COSW0 + (2 * math.sqrt(A) * alpha))
b1 = 2 * A * ((A - 1) - ((A + 1) * COSW0))
b2 = A * ((A + 1) - (A - 1) * COSW0 - (2 * math.sqrt(A) * alpha))
a0 = (A + 1) + ((A - 1) * COSW0) + (2 * math.sqrt(A) * alpha)
a1 = -2 * ((A - 1) + ((A + 1) * COSW0))
a2 = (A + 1) + ((A - 1) * COSW0) - (2 * math.sqrt(A) * alpha)
num = [b0, b1, b2]
den = [a0, a1, a2]
sos = signal.tf2sos(num, den)
return sos
def bandpass(w0, Q):
#WROTE THIS FUNCTION, LEFT IT UNUSED IN FINAL IMPLEMENTATION
#BPF, modeled from:
#H(s) = s / (s^2 + s/q + 1)
COSW0 = math.cos(w0)
alpha = math.sin(w0) / (2 * Q)
b0 = Q * alpha #= SINW0/2
b1 = 0
b2 = -b0
a0 = a + alpha
a1 = -2 * COSW0
a2 = 1 - alpha
num = [b0, b1, b2]
den = [a0, a1, a2]
sos = signal.tf2sos(num, den)
return sos
def lowpass(w0, Q):
#LPF, modeled from:
#H(s) = 1/(s^2 + s/Q + 1)
COSW0 = math.cos(w0)
alpha = math.sin(w0) / (2 * Q)
b0 = (1 - COSW0) / 2
b1 = 1 - COSW0
b2 = b0
a0 = 1 + alpha
a1 = -2 * COSW0
a2 = 1 - alpha
num = [b0, b1, b2]
den = [a0, a1, a2]
sos = signal.tf2sos(num, den)
return sos
def signal(self):
"""
Deliver the signal.
Returns
-------
Array of floats
The resulting signal as an array of length :attr:`~SignalGenerator.numsamples`.
"""
rnd_gen = RandomState(self.seed)
ma = self.handle_empty_coefficients(self.ma)
ar = self.handle_empty_coefficients(self.ar)
sos = tf2sos(ma, ar)
ntaps = ma.shape[0]
sdelay = round(0.5 * (ntaps - 1))
wnoise = self.rms * rnd_gen.standard_normal(
self.numsamples +
sdelay) # create longer signal to compensate delay
return sosfilt(sos, x=wnoise)[sdelay:]
def lowpass(w0, Q):
#RETURNS SOS that can be used in SOSFILT
#LPF
#H(s) = 1/(s^2 + s/Q + 1)
COSW0 = math.cos(w0)
alpha = math.sin(w0) / (2 * Q)
b0 = (1 - COSW0) / 2
b1 = 1 - COSW0
b2 = b0
a0 = 1 + alpha
a1 = -2 * COSW0
a2 = 1 - alpha
num = [b0, b1, b2]
den = [a0, a1, a2]
sos = signal.tf2sos(num, den)
return sos
def band_pass_filter(signal, fs, start_freq, end_freq, margin_rate):
"""
Description
- High Pass Filter
Input
:param signal:list, 입력 신호
:param fs: Float, 샘플링 주파수 (sampling frequency)
:param start_freq: Float, 시작 주파수 (passband)
:param end_freq: Float, 끝 주파수 (passband)
:param margin_rate: Float, 마진율
Output
:return list, 필터링된 신호
Example
> signal = [0, 1, 2, 3, 2, 1, 0, -1, -2, -3, -2, -1]
> fs = 0.1
> start_freq = 0.001
> end_freq = 0.003
> band_pass_filter(signal, fs, start_freq, end_freq, 0.08)
[0.63095463 0.95862525 1.23888854 1.41245392 1.44684504 1.36618891
1.22107957 1.05946482 0.92849059 0.87631723 0.92292086 1.02981141]
"""
#
fn = fs / 2
wp = np.divide([start_freq, end_freq], fn)
ws = np.divide([start_freq * margin_rate, end_freq / margin_rate], fn)
n, wn = buttord(wp, ws, 1, 10) # 'Butterworth Filter'의 차수(order) 구하기
b, a = butter(n, wn, btype='band') # 'Butterworth Filter'의 a와 b 파라메터 생성
sos = tf2sos(b, a)
signal = np.array(signal).reshape(-1)
filtered_signal = sosfiltfilt(sos, signal)
return filtered_signal
def output_filter(B, A, name, show_response = False, emit_test_ir = False, impulse_resp_length = 64):
sos = signal.tf2sos(B, A)
if show_response:
B, A = signal.sos2tf(sos)
w, h = signal.freqz(B, A, worN=2**12)
plt.title('Digital filter frequency response')
plt.semilogx(w*fs/(2.0*np.pi), 20 * np.log10(abs(h)), label = 'A_orig')
plt.ylim(-50, 20)
plt.ylabel('Amplitude [dB]', color='b')
plt.xlabel('Frequency [rad/sample]')
plt.grid()
plt.show()
filter_q = 31
max_q_adjust = 0
for bq in range(len(sos)):
sos[bq] /= sos[bq][3]
abs_sum = sum(abs(sos[bq])) - 1.0
m = int(np.ceil(np.log2(abs_sum))) #TODO check this works for -ve abs_sums
max_q_adjust = max(max_q_adjust, m)
max_q_adjust -= 1 #to take advantage of 64 bit maccs
filter_q -= max_q_adjust
#TODO check for -ve max_q_adjust
sos_quantised = np.zeros(np.shape(sos))
int_max = np.int64(int32_max) / 2**max_q_adjust
print 'const int32_t filter_coeffs_' + name + '[] = {'
for bq in range(len(sos)):
print '\t',
for i in range(3):
v = np.int32(np.float64(int_max) * sos[bq][i])
print str(v) + ', ' ,
sos_quantised[bq][i] = np.float64(v) / np.float64(int_max)
for i in range(4, 6):
v = int(np.float64(int_max) * -sos[bq][i])
sos_quantised[bq][i] = np.float64(-v) / np.float64(int_max)
print str(v) + ', ' ,
print
sos_quantised[bq][3] = 1.0
print '};'
print 'const uint32_t num_sections_' + name + ' = ' + str(len(sos)) + ';'
print 'const uint32_t q_format_' + name + ' = ' + str(filter_q) + ';'
print 'int32_t filter_state_'+ name +'[' +str(len(sos)) + '*DSP_NUM_STATES_PER_BIQUAD] = {0};'
d = np.zeros(impulse_resp_length)
d[0] = 1
B_q, A_q = signal.sos2tf(sos_quantised)
filter_impulse_response = signal.lfilter(B_q, A_q, d)
if emit_test_ir:
print 'const unsigned impulse_resp_length_' + name + ' = ' + str(impulse_resp_length)+';'
print 'const int32_t expected_ir_' + name + '[' + str(impulse_resp_length) + '] = {'
for i in range(impulse_resp_length):
s = str(int(int32_max * filter_impulse_response[i])) + ', '
if i%8 == 7:
print s
else:
print s,
print '};'
return