Fractional amplitude of modulation from pulsed fraction
If the pulsed profile is defined as p = mean * (1 + a * sin(phase)),
we define “pulsed fraction” as 2a/b, where b = mean + a is the maximum and a is the amplitude of the modulation.
Hence, a = pf / (2 - pf)
>>> a_from_pf(1) 1.0 >>> a_from_pf(0) 0.0