Documentation

dsp.LPCToRC System object

Package: dsp

Convert linear prediction coefficients to reflection coefficients

Description

The LPCToRC object converts linear prediction coefficients to reflection coefficients.

To convert LPC to reflection coefficients:

  1. Define and set up your LPC to RC converter. See Construction.

  2. Call step to convert LPC according to the properties of dsp.LPCToRC. The behavior of step is specific to each object in the toolbox.

Construction

H = dsp.LPCToRC returns an LPC to RC System object™, H, that converts linear prediction coefficients (LPC) to reflection coefficients (RC).

H = dsp.LPCToRC('PropertyName',PropertyValue,...) returns an LPC to RC conversion object, H, with each specified property set to the specified value.

Properties

PredictionErrorOutputPort

Enable normalized prediction error power output

Set this property to true to return the normalized error power as a vector with one element per input channel. Each element varies between zero and one. The default is true.

ExceptionOutputPort

Produces output with stability status of filter represented by LPC coefficients

Set this property to true to return the stability status of the filter. A logical value of 1 indicate a stable filter. A logical value of 0 indicate an unstable filter. The default is false.

NonUnityFirstCoefficientAction

Action to take when first LPC coefficient is not 1

Specify the action that the object takes when the first coefficient of each channel of the LPC input is not 1. Select Replace with 1 or Normalize. The default is Replace with 1.

Methods

cloneCreate LPC to RC object with same property values
getNumInputsNumber of expected inputs to step method
getNumOutputsNumber of outputs of step method
isLockedLocked status for input attributes and nontunable properties
releaseAllow property value and input characteristics changes
stepConvert columns of linear prediction coefficients to reflection coefficients

Examples

Convert the linear prediction coefficients to reflection coefficients:

load mtlb

hlevinson = dsp.LevinsonSolver;
hlevinson.AOutputPort = true;
hlevinson.KOutputPort = false;

hac = dsp.Autocorrelator;
hlpc2rc = dsp.LPCToRC;
hac.MaximumLagSource = 'Property';

% Compute autocorrelation for lags between [0:10]
hac.MaximumLag = 10; 
a = step(hac, mtlb);
A = step(hlevinson, a); % Compute LPC coefficients
[K, P] = step(hlpc2rc, A); % Convert to RC

Algorithms

This object implements the algorithm, inputs, and outputs described on the LPC to/from RC block reference page. The object properties correspond to the block parameters, except:

  • There is no object property that corresponds to the Type of conversion block parameter. The object always converts LPC to RC.

  • The NonUnityFirstCoefficientAction object property corresponds to the If first input value is not 1 block parameter. There is neither a Normalize and warn nor an Error option for the object.

Was this topic helpful?