National Instruments Car Stereo System 320571-01 用户手册

Computes the deconvolution of the input
sequences X and Y.  The convolution operation
can be realized using Fourier identities because

x(t) * y(t) 

⇔

  X(f) Y(f)

is a Fourier transform pair, where the symbol *

denotes convolution, and the deconvolution is
the inverse of the convolution operation.  If h(t) is the signal resulting from the deconvolution of the signals x(t) and
y(t), the VI obtains h(t) using the equation

h(t)  = F

-1

{ }

X(f)
Y(f)

 ,

where X(f) is the Fourier transform of x(t), and

Y(f) is the Fourier transform of y(t).

The VI performs the discrete implementation of the deconvolution using the following steps.

1.

Compute the Fourier transform of the input sequence X * Y.

2.

Compute the Fourier transform of the input sequence Y.

3.

Divide the Fourier transform of X * Y by the Fourier transform of Y.  Call the new sequence H.

4.

Compute the inverse Fourier transform of H to obtain the deconvoluted sequence X.

Cxy is a DSP Handle Cluster that indicates the memory buffer on the DSP board that contains the input
signal array Cxy.  The number of elements in Cxy must be greater than or equal to the number of
elements in Y.

Y is a DSP Handle Cluster that indicates the memory buffer on the DSP board that contains the input
signal array Y.

X in is a DSP Handle Cluster that indicates the memory buffer on the DSP board that will contain the
deconvolution results.

Note: The size of X in must be n elements long, although only (n-m+1) elements are valid.  n is the

size of Cxy, m is the size of Y.

X out is a DSP Handle Cluster that is identical to X in, but with the deconvolution results already stored
in the memory buffer on the DSP board.

error in (no error) contains the error information from a previous VI.  If an error occurs, it is passed out
error out and no other calls are made.

error out contains the error information for this call.

Note: The deconvolution operation is a numerically unstable operation, and it is not always possible to solve the

system numerically.  Computing the deconvolution via FFTs is perhaps the most stable generic algorithm
that does not require sophisticated DSP techniques.  However, it is not free of errors (for example, when
there are zeros in the Fourier transform of the input sequence Y).