aa              = -3.89347     
bb              = 2.62643      
dd              = 1.10409      
ee              = 0.264364     
ff              = -6.75644     
#off=0.5
g(x) = bb*tanh(aa*(x-dd))+cc +bb*tanh(-aa*(x+ee)) +a+b*(x-h)+c*(x-h)**2+d*(x-h)**3+e*(x-h)**4+f*(x-h)**5+g*(x-h)**6+j*(x-h)**7
gg(x) = bb*tanh(aa*(x-dd))+cc +bb*tanh(-ff*(x+ee))
hh(x) = bb*tanh(aa*(x-dd+0.3))+cc +bb*tanh(-ff*(x+ee+0.3))

set yrange [-0.5:]
set xrange [-2:4]
fit gg(x) 'pulse_60cm.dat' u ($1/2.5):2 via aa,bb,dd,ee,ff
set xrange [-2:4]
normalization = hh(0)
plot gg(x)/hh(0), 'pulse_60cm.dat' u ($1/2.5):($2/normalization), hh(x)/hh(0)

#fit g(x) 'pulse.dat' via aa,bb,cc,dd,ee,a,b,c,d,e,f,g,h,j
#fit g(x) 'pulse.dat' via a,b,c,d,e,f,g,h,j