### Calculates g and C_diff from small signal simulation ###
######   in forward bias as a function of frequency   ######

contact = 'emitter';

ac_data = getresult('CHARGE','ac_'+contact);

dI = pinch(getdata('CHARGE','ac_'+contact,'dI'));
dV = pinch(getdata('CHARGE','ac_'+contact,'dV_'+contact));
f = pinch(getdata('CHARGE','ac_'+contact,'f'));
w = 2*pi*f;
Vbias = pinch(getdata('CHARGE','ac_'+contact,'V_'+contact));

# get the length of voltage and frequency sweeps

kern = size(dI);
nV = kern(1);
nf = kern(2);

Gcomp = dI/dV;
Gcomp = Gcomp(nV,1:nf);
G = real(Gcomp);
C = imag(Gcomp)/w;

# normalize conductance and capaciatnce with LF values

G_norm = G/G(1);
C_norm = C/C(1);

plot(f,G_norm,C_norm,'Freq (Hz)','Gdiff/Gdiff_0, Cdiff/Cdiff_0','','log10x,log10y');
legend('g_forward','C_forward');