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dsp.LSFToLPC System object

Package: dsp

Convert line spectral frequencies to linear prediction coefficients


The LSFToLPC object converts line spectral frequencies to linear prediction coefficients.

To convert LSF to LPC:

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

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

    Note:   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.


H = dsp.LSFToLPC returns an LSF to LPC System object, H, which converts line spectral frequencies (LSFs) to linear prediction coefficients (LPCs).


cloneCreate LSF to LPC 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 input line spectral frequencies to linear prediction coefficients


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).

 a = [1.0000 0.6149 0.9899 0.0000 0.0031 -0.0082]'
 hlpc2lsf = dsp.LPCToLSF;
 ylsf = hlpc2lsf(a);
 hlsf2lpc = dsp.LSFToLPC;
 ylpc = hlsf2lpc(ylsf);
a =


Check if values in ylpc are the same as in a.

ylpc =



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

The object does not have a property that corresponds to the Input block parameter. The object's behavior corresponds to the block's behavior when you set the Input parameter to LSF in range (0 pi).

Introduced in R2012a

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