function TRAIN = itrain( N0, N)
% TRAIN = itrain( N0, N)
%
% Create an impulse train of length N samples
% with a period of N0, scaled to have an average energy 
% of 1.0.  First impulse is TRAIN(1).
%

TRAIN = zeros(N,1);
TRAIN(1:N0:N) = sqrt(N0)*ones(ceil(N/N0),1);

