This is machine translation

Translated by Microsoft
Mouseover text to see original. Click the button below to return to the English version of the page.

Note: This page has been translated by MathWorks. Please click here
To view all translated materials including this page, select Japan from the country navigator on the bottom of this page.

dsp.LPCToRC System object

Convert linear prediction coefficients to reflection coefficients


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.


Starting in R2016b, instead of using the step method to perform the operation defined by the System object™, you can call the object with arguments, as if it were a function. For example, y = step(obj,x) and y = obj(x) perform equivalent operations.


lpc2rc = dsp.LPCToRC returns an LPC to RC System object, lpc2rc, that converts linear prediction coefficients (LPC) to reflection coefficients (RC).

lpc2rc = dsp.LPCToRC('PropertyName',PropertyValue,...) returns an LPC to RC conversion object, lpc2rc, with each specified property set to the specified value.



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.


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.


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.


stepConvert columns of linear prediction coefficients to reflection coefficients
Common to All System Objects

Create System object with same property values


Expected number of inputs to a System object


Expected number of outputs of a System object


Check locked states of a System object (logical)


Allow System object property value changes


expand all

Note: This example runs only in R2016b or later. If you are using an earlier release, replace each call to the function with the equivalent step syntax. For example, myObject(x) becomes step(myObject,x).

Convert the linear prediction coefficients to reflection coefficients:

load mtlb

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

ac = dsp.Autocorrelator;
lpc2rc = dsp.LPCToRC;
ac.MaximumLagSource = 'Property';

Compute autocorrelation for lags between [0:10]

ac.MaximumLag = 10; 
a = ac(mtlb);
A = levinson(a); % Compute LPC coefficients
[K, P] = lpc2rc(A); % Convert to RC


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.

Extended Capabilities

Introduced in R2012a

Was this topic helpful?