Apparatus for the cross-correlation of a pair of complex sampled signals
First Claim
1. Apparatus for cross-correlating first and second complex digital data signals, comprising:
- a multiplier section having a first pipeline CORDIC rotator means with a plurality N of sequential stages, receiving separate and independent imaginary and real portions of the first complex data signal, for rotating the independent imaginary and real portions through predetermined decreasing angles α
to progressively reduce the magnitude of the imaginary-portion of the first complex data signal toward zero in each of the plurality N of sequential stages, and providing output data equal to the absolute value of the first complex data signal; and
a multiplicand section having a plurality M of additional pipeline CORDIC rotator means, each means having a like plurality N of sequential stages, for modifying the read and imaginary portions of the second complex data signal to cause rotation, responsive to a selection signal, through each of like angles α and
with a rotation in each j-th rotator means, where 1≦
j≦
(M-1), being progressively delayed by one common delay time interval greater than a total time delay in the previous (j-1)-th rotator means; and
means for arithmetically processing the modified second complex data signal from all of the M additional rotator means to provide, at any one time one set of data corresponding to the cross-correlation of both complex signals at that time.
1 Assignment
0 Petitions
Accused Products
Abstract
Apparatus for the cross-correlation of two complex sampled digital data signals X and Y uses a first N-stage CORDIC rotator of pipeline sequential form for rotating each of the real and imaginary data portions of the first (X) complex sampled signal sequentially through a summation of angles θ=ξi αi where ξi =+1 or -1, α1 =90° and αn-2 =tan-1 (2-n) for n=0, 1, 2, 3, . . . N-2) until XIm is approximately zero and a substantially zero phase angle is reached. The sign from each i-th stage, of this first pipeline is also utilized to determine the sign of rotation in each like-positioned i-th stage of a plurality M of additional CORDIC pipeline rotators, where M is the total number of time delays at which the cross-correlation function is evaluated. The real and imaginary portions of the complete M-th interval cross-correlation product are each obtained by multiplying the associated complex output of each of the Y pipeline rotators by the first pipeline magnitude signal output; N samples are then summed to provide at the j-th rotator output the appropriate pair of the real and imaginary parts of the j-th complex digital data output sample C(j).
44 Citations
6 Claims
-
1. Apparatus for cross-correlating first and second complex digital data signals, comprising:
- a multiplier section having a first pipeline CORDIC rotator means with a plurality N of sequential stages, receiving separate and independent imaginary and real portions of the first complex data signal, for rotating the independent imaginary and real portions through predetermined decreasing angles α
to progressively reduce the magnitude of the imaginary-portion of the first complex data signal toward zero in each of the plurality N of sequential stages, and providing output data equal to the absolute value of the first complex data signal; and
a multiplicand section having a plurality M of additional pipeline CORDIC rotator means, each means having a like plurality N of sequential stages, for modifying the read and imaginary portions of the second complex data signal to cause rotation, responsive to a selection signal, through each of like angles α and
with a rotation in each j-th rotator means, where 1≦
j≦
(M-1), being progressively delayed by one common delay time interval greater than a total time delay in the previous (j-1)-th rotator means; and
means for arithmetically processing the modified second complex data signal from all of the M additional rotator means to provide, at any one time one set of data corresponding to the cross-correlation of both complex signals at that time. - View Dependent Claims (2, 3, 4, 5, 6)
- a multiplier section having a first pipeline CORDIC rotator means with a plurality N of sequential stages, receiving separate and independent imaginary and real portions of the first complex data signal, for rotating the independent imaginary and real portions through predetermined decreasing angles α
Specification