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# latcfilt() - Signal Processing

### Syntax

### Example

### Output / Return Value

### Limitations

### Alternatives / See Also

### Reference

When filtering data, lattice coefficients can be used to representFIR filtersAll-pole IIR filtersAllpass IIR filtersGeneral IIR filters[f,g] = latcfilt(k,x) filters x with the FIR lattice coefficients in the vector k. The forward lattice filter result is f and g is the backward filter result. If |k|≤1, f corresponds to the minimum-phase output, and g corresponds to the maximum-phase output.If k and x are vectors, the result is a (signal) vector. Matrix arguments are permitted under the following rules:If x is a matrix and k is a vector, each column of x is processed through the lattice filter specified by k.If x is a vector and k is a matrix, each column of k is used to filter x, and a signal matrix is returned.If x and k are both matrices with the same number of columns, then the ith column of k is used to filter the ith column of x. A signal matrix is returned.[f,g] = latcfilt(k,v,x) filters x with the IIR lattice coefficients k and ladder coefficients v. Both k and v must be vectors, while x can be a signal matrix.[f,g] = latcfilt(k,1,x) filters x with the IIR lattice specified by k, where k and x can be vectors or matrices. f is the all-pole lattice filter result and g is the allpass filter result.[f,g,zf] = latcfilt(...,'ic',zi) accepts a length-k vector zi specifying the initial condition of the lattice states. Output zf is a length-k vector specifying the final condition of the lattice states.[f,g,zf] = latcfilt(...,dim) filters x along the dimension dim. To specify a dim value, the FIR lattice coefficients k must be a vector and you must specify all previous input parameters in order. Use the empty vector [ ] for any parameters you do not want to specify. zf returns the final conditions in columns, regardless of the shape of x.

[f,g] = latcfilt(k,x)[f,g] = latcfilt(k,v,x)[f,g] = latcfilt(k,1,x)[f,g,zf] = latcfilt(...,'ic',zi)[f,g,zf] = latcfilt(...,dim)

FIR Lattice FilterOpen This ExampleGenerate a signal with 512 samples of white Gaussian noise.x = randn(512,1); Filter the data with an FIR lattice filter. Specify the reflection coefficients so that the lattice filter is equivalent to a 3rd-order moving average filter.[f,g] = latcfilt([1/2 1],x); Plot the maximum- and minimum-phase outputs of the lattice filter in separate plotssubplot(2,1,1) plot(f) title('Maximum-Phase Output') subplot(2,1,2) plot(g) title('Minimum-Phase Output')