(To be removed) Convert linear prediction coefficients to line spectral pairs
dsp.LPCToLSP will be removed in a future release. Use poly2lsf instead. For more information, see Compatibility Considerations.
The LPCToLSP object converts linear prediction
coefficients to line spectral pairs.
To convert LPC to LSP:
Define and set up your LPC to LSP converter. See Construction.
Call step to convert LPC according to the
properties of dsp.LPCToLSP. 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.
lpc2lsp = dsp.LPCToLSP returns a System
object, lpc2lsp, that converts linear
prediction coefficients (LPCs) to line spectral pairs (LSPs).
lpc2lsp = dsp.LPCToLSP('
returns an PropertyName',PropertyValue,...)LPC to LSF
System
object, lpc2lsp, with each specified property
set to the specified value.
|
Number of coarse subintervals used for finding roots (LSP values) Specify the number of coarse subintervals, n, used for
finding line spectral pairs (LSP) values, as a positive scalar integer.
LSPs, which are the roots of two particular polynomials related to the input
LPC polynomial, always lie in the range (–1, 1). The System
object finds these roots using the Chebyshev polynomial root finding
method. The object divides the interval (–1, 1) into n
subintervals and looks for roots in each subinterval. If
n is set to too small a number in relation to the LPC
polynomial order, the object can fail to find some of the roots. The default
is |
|
Value of bisection refinement used for finding roots Specify the root bisection refinement value, k, that the Chebyshev polynomial uses in the root finding method. For each line spectral pair (LSP) the output is within of the actual LSP value. Here n is
the value of the points for finding the roots. The
|
|
Produces output with validity status of LSP output Set this property to |
|
Enable overwriting invalid output with previous output Specify the action that the object takes for invalid LSP outputs. When you
set this property to |
|
Source of values for first output when output is invalid Specify the source of values for the first output when the output is
invalid as |
|
Value of first output Specify a numeric vector of LSP values for overwriting an invalid first
output. The length of this vector must be one less than the length of the
input LPC vector. For multichannel inputs, set this property can to a matrix
with the same number of channels as the input or one vector that you apply
to every channel. The default is an empty vector. This property applies only
when you set the |
|
First coefficient nonunity action Specify the action that the object takes when the first coefficient of
each channel of the LPC input is not equal to |
| reset | Reset values for overwriting invalid outputs to their initial values |
| step | Convert linear prediction coefficients to line spectral pairs |
| Common to All System Objects | |
|---|---|
release | Allow System object property value changes |
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 line spectral pairs.
a = [1.0000 0.6149 0.9899 0.0000 0.0031 -0.0082]';
lpc2lsp = dsp.LPCToLSP;
y = lpc2lsp(a); % Convert to LSP coefficientsThis object implements the algorithm, inputs, and outputs described on the LPC to LSF/LSP Conversion block reference page. The object properties correspond to the block parameters, except:
| No object property corresponds to the Output block parameter. The object only supports LSP outputs. |