Filter Design Toolbox

Indexing into a Cell Array of Vectors or Matrices

To index into a cell array of matrices (as opposed to a cell array of cell arrays), you only need one set of braces to index into the cell array.

Here's an example of accessing cell array information from a quantized filter with a single section. In this case, the filter coefficient information is stored as a cell array of vectors.

Example -- Accessing Coefficient Information from Filters with One Section

You can specify a sample quantized filter by typing

• Hq = qfilt('ref',{[1 .5],[1 .7 .89]});
  Hq.ReferenceCoefficients
  
  ans = 
      [1x2 double]    [1x3 double]
  

Notice that the filter reference coefficients are stored in a two-by-one cell array of vectors, the way you specified them.

Suppose that you want to retrieve the values stored in this property.

Use curly braces to index into and access the first entry of the cell array Hq.ReferenceCoefficients. You can use the shorthand for property names when you index into the properties of Hq.

• Hq.ref{1}
  
  ans =
      1.0000    0.5000
  

Similarly,

• Hq.ref{2}
  
  ans =
      1.0000    0.7000    0.8900
  

To access the third entry in Hq.ref{2}, index into Hq.ref{2} in the standard way.

• Hq.ref{2}(3)
  
  ans =
      0.8900
  

Using Cell Arrays

Indexing into a Cell Array of Cell Arrays