Multiplier circuit configurable for real or complex operation
AssigneeXilinx, Inc.
InventorBernard J. New
Life of this patent
Estimating the term…
Abstract
A configurable multiplier circuit for multiplying both real and complex numbers is included in a PLD. In one embodiment, the circuit includes two adder trees. Multiplexers are used such that a conventional multiplier component is not required. The circuit is programmable to operate in one of two modes. In a first mode, the circuit multiplies the four parts of two complex numbers and outputs two values, the real portion of the product and the imaginary portion of the product. In a second mode, each of two portions of the circuit multiplies two pairs of real numbers and outputs the products.
Claims8
A circuit, having inputs A, B, C, and, D, for multiplying a multiplicand by a multiplier, the circuit comprising:
- a first circuit portion, comprising:
- a first multiplexer having a first data input, a second data input, a third data input, a fourth data input, a first select input, a second select input, and a first multiplexer output, wherein A is present on the first data input, A plus a one's complement of B is present on the second data input, the one's complement of B is present on the third data input, and a value zero is present on the fourth data input;
- and
- a first adder tree having a first input, a second input, and an output, the first multiplexer output of the first circuit portion being coupled to the first input of the first adder tree, a difference of a product of A times C minus a product of B times D being output onto the output of the first adder tree;
- and
- a second circuit portion, comprising:
- a first multiplexer having a first data input, a second data input, a third data input, a fourth data input, a first select input, a second select input, and a first multiplexer output, wherein B is present on the first data input, B plus A is present on the second data input, A is present on the third data input, and the value zero is present on the fourth data input;
- and
- a second adder tree having a first input, a second input, and an output, the first multiplexer output of the second circuit portion being coupled to the first input of the second adder tree, a sum of a product of A times D plus a product of B times C being output onto the output of the second adder tree.
Dependencies are inferred from the claim text.