What is your SNR requirement? You need that information too. The albersheim function in Phased Array System Toolbox does not give you directly that information, but you can obtain a curve using that function and then try to derive the information from there, e.g.,
N = 1:100
for m = length(N):-1:1
snr(m) = albersheim(0.5,1.3e-7,N(m));
end
plot(N,snr); xlabel('N'); ylabel('SNR (dB)')
From the curve, if your SNR is about 0 dB, then you need approximately 40 pulses.
HTH
