get_burst_sequence.m

source Matlab traites the UWB

%
% function [y,Lb] =
% get_burst_sequence(pulse,polarity,samples_per_chip,BURST_LENGTH,PACKET_LENGTH)
%
function [y,Lb] = get_burst_sequence(pulse,polarity,samples_per_chip, ...
                                      BURST_LENGTH,PACKET_LENGTH)

Lp = length(polarity);
Lb = (BURST_LENGTH-1)*samples_per_chip+length(pulse)-1;

pulse_start = zeros(1,Lb*PACKET_LENGTH);

pulse_start_idx = cumsum(ones(BURST_LENGTH,1)*samples_per_chip)-samples_per_chip;
burst_start_idx = cumsum(ones(1,PACKET_LENGTH)*Lb)-Lb;
% Index of the start of each pulse
signal_idx = repmat(pulse_start_idx,1,PACKET_LENGTH) + ...
    repmat(burst_start_idx,BURST_LENGTH,1)+1;


% Is it faster than the convolution?
offset = 0:1:length(pulse)-1;
signal_idx = reshape(signal_idx,1,BURST_LENGTH*PACKET_LENGTH);
for k = 1:length(signal_idx)-1
  pulse_start(signal_idx(k)+offset) = ...
      polarity(k)*pulse + pulse_start(signal_idx(k)+offset);
end
offset=1:1:length(pulse_start)-signal_idx(end);
pulse_start(signal_idx(end)+offset) = ...
      polarity(k)*pulse(offset) + pulse_start(signal_idx(end)+offset);
y = pulse_start;

% $$$ pulse_start(reshape(signal_idx,1,BURST_LENGTH*PACKET_LENGTH)) = polarity;
% $$$ y = conv(pulse,pulse_start);
% $$$ y = y(1:Lb*PACKET_LENGTH);