%
% FUNCTION 8.9 : "cp0802_rmsds"
%
% Evaluates the root mean square dealy spread 'rmsds'
% of a channel impulse response 'h' sampled
% at frequency 'fc'
%
% Programmed by Guerino Giancola
%


function [rmsds] = cp0802_rmsds(h,fc)

% ---------------------------------------------
% Step One - Evaluation of the rms Delay Spread
% ---------------------------------------------

dt = 1 / fc;        % sampling time

ns = length(h);     % number of samples representing
                    % the channel impulse response

                    
time = (0 : dt : (ns-1)*dt);
den = sum(h.^2);
num1 = sum(time.*(h.^2));
num2 = sum((time.^2).*(h.^2));
rmsds = sqrt((num2/den)-(num1/den)^2);