Gain at cutoff frequency of gaussian filter

[demolpc]

In your paper, you said the Gain at cutoff frequency(3Hz) of gaussian filter is -60dB. How did you calculate this value? In my calculation, it seems to be around -0.6dB. Here is my code:

import numpy as np
import matplotlib.pyplot as plt
from scipy import signal

L = 13
sigma = 0.35
half_l = (L-1)/2
x = (np.arange(L)-half_l)/half_l
gaussian_coeff = np.exp(-0.5 * (x / sigma) ** 2)
# print(gaussian_coeff)
coeff_sum = np.sum(gaussian_coeff)
gaussian_coeff /= coeff_sum

w, h = signal.freqz(gaussian_coeff, fs=100)
fig, ax1 = plt.subplots()
ax1.plot(w, 20*np.log10(abs(h)), label='fir')
plt.show()