from math import log

ln2 = log(2)

r1 = "8.7"
r1M = "M"
r2 = "35"
r2M = "M"
c = "10"
cM = "u"
def si(a):
    return {
        "u" : 1/1000000.,
        "m" : 1/1000.,
        "k" : 1000,
        "M" : 1000000,
    }.get(a, 1)

r1 = float(r1) * si(r1M)
c = float(c) * si(cM)
r2 = float(r2) * si(r2M)
t1 = ln2 * c * (r1 + r2)
t2 = ln2 * c * (r1)
p = t1 + t2
f = 1/p
d = t1/p * 100
print "T1", t1
print "T2", t2
print "period", p
print "freq", f
print "duty cycle", d, "%"

T1 302.905317905
T2 60.3038047087
period 363.209122613
freq 0.00275323481086
duty cycle 83.3969465649 %