# This is what the value of K will be at the end (in dB):
kend = 10**((-6*np.log2(self.w2/self.w1))/20)
# dB to rational number.
k = np.log(kend)/self.T

# Making reverse probe impulse so that convolution will just
# calculate dot product. Weighting it with exponent to acheive
# 6 dB per octave amplitude decrease.
self.reverse_pulse = self.probe_pulse[-1::-1] * \
    np.array(list(\
        map(lambda t: np.exp(t*k), np.arange(self.T))\
        )\
    )