summation

hi,

how to calculate summation of absolute value of incoming digital data over a cycle period for example 64 samples in a cycle using matlab or simulink

∑abs|d1(k)| for k=0 to 64

Answer 1

[Laura Proctor]

d = randn(64,1);
s = sum(abs(d))

[Lisa Justin]

what about the interval?

Answer 2

[MarkB]

There are a couple options available:

• You could chain a series of 64 unit delays together and run a branched signal off of each one into a summation block.
• You could use MATLAB function block ("Embedded MATLAB" in older releases) and have something in the body like:

function y = avg64( u )
persistent x;
if( isemtpy( x ) == true )
  x = zeros( 64, 1 );
end

x = [ abs(u), x( 2 : end ) ];
y = x;

return;
end

• I believe that the communication blockset has some buffer blocks that will accumulate a rolling set of samples, which you could then feed to a sum block.
• There is probably a way to write this as a transfer function too.