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dsp.LPCToAutocorrelation System object

Convert linear prediction coefficients to autocorrelation coefficients


The LPCToAutocorrelation System object™ converts linear prediction coefficients to autocorrelation coefficients.

To convert LPC to autocorrelation coefficients:

  1. Define and set up your LPC to autocorrelation object. See Construction.

  2. Call step to convert LPC according to the properties of dsp.LPCToAutocorrelation. 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.


lpc2ac = dsp.LPCToAutocorrelation returns an LPC to autocorrelation System object, lpc2ac, that converts linear prediction coefficients (LPC) to autocorrelation coefficients.

lpc2ac = dsp.LPCToAutocorrelation('PropertyName',PropertyValue,...) returns an LPC to autocorrelation conversion object, lpc2ac, with each specified property set to the specified value.



Enable prediction error power input

Choose how to select the prediction error power. When you set this property to true, you must specify the prediction error power as a second input to the step method. When you set this property to false, the object assumes that the prediction error power is 1. 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.


stepAutocorrelation coefficients from LPC 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 autocorrelation coefficients.

a = [1.0 -1.4978 1.4282 -1.3930 0.9076 -0.3855 0.0711].';
lpc2ac = dsp.LPCToAutocorrelation;
ac = lpc2ac(a);


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

The object does not have a property that corresponds to the Type of Conversion block parameter. The object's behavior corresponds to the block's behavior when you set the Type of Conversion parameter to LPC to autocorrelation.

Extended Capabilities

Introduced in R2012a

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