cordiccexp
CORDIC-based approximation of complex exponential
Syntax
y = cordiccexp(theta,niters)
Description
computes y
= cordiccexp(theta
,niters
)cos
(theta
)
+ j*sin
(theta
)
using a CORDIC algorithm approximation. y
contains
the approximated complex result.
Input Arguments
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|
|
|
Output Arguments
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Examples
The following example illustrates the effect of the number of
iterations on the result of the cordiccexp
approximation.
wrdLn = 8; theta = fi(pi/2, 1, wrdLn); fprintf('\n\nNITERS\t\tY (SIN)\t ERROR\t LSBs\t\tX (COS)\t ERROR\t LSBs\n'); fprintf('------\t\t-------\t ------\t ----\t\t-------\t ------\t ----\n'); for niters = 1:(wrdLn - 1) cis = cordiccexp(theta, niters); fl = cis.FractionLength; x = real(cis); y = imag(cis); x_dbl = double(x); x_err = abs(x_dbl - cos(double(theta))); y_dbl = double(y); y_err = abs(y_dbl - sin(double(theta))); fprintf('%d\t\t%1.4f\t %1.4f\t %1.1f\t\t%1.4f\t %1.4f\t %1.1f\n',... niters, y_dbl, y_err,(y_err * pow2(fl)),... x_dbl, x_err,(x_err * pow2(fl))); end fprintf('\n');
The output table appears as follows:
NITERS Y (SIN) ERROR LSBs X (COS) ERROR LSBs ------ ------- ------ ---- ------- ------ ---- 1 0.7031 0.2968 19.0 0.7031 0.7105 45.5 2 0.9375 0.0625 4.0 0.3125 0.3198 20.5 3 0.9844 0.0156 1.0 0.0938 0.1011 6.5 4 0.9844 0.0156 1.0 -0.0156 0.0083 0.5 5 1.0000 0.0000 0.0 0.0312 0.0386 2.5 6 1.0000 0.0000 0.0 0.0000 0.0073 0.5 7 1.0000 0.0000 0.0 0.0156 0.0230 1.5
More About
More About
Algorithms
Extended Capabilities
Version History
Introduced in R2010a