function plotds_range (x, y, colour,ds,range)
if nargin == 1
plot(x(range));
elseif nargin == 2
plot(x(range),y(range));
elseif nargin == 3
plot(x(range),y(range),colour)
else
plot(downsample(x(range),ds),downsample(y(range),ds),colour);
end
end