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--
-- Copyright 2021 Ettus Research, a National Instruments Brand
--
-- SPDX-License-Identifier: LGPL-3.0-or-later
--
-- Module: scale_2x
--
-- Description:
--
-- This block does the scaling of IQ data by 2. The data from the mixer is
-- 1/2 the full scale and the upper two bits will only have the signed bits,
-- so it is okay to multiply the data by 2 and resize it back to 16 bits.
--
-- Parameters:
--
-- kDataWidth: Data width, should be a multiple of 16 bits.
--
library IEEE;
use IEEE.std_logic_1164.all;
use IEEE.numeric_std.all;
library WORK;
use WORK.PkgRf.all;
entity scale_2x is
generic(
kDataWidth : integer range 1 to 256 := 32
);
port(
-- [..Q1,I1,Q0,I0] (I in LSBs). Each I and Q data is 16 bits wide, but
-- since the data is only 1/2 full scale. Useful information is only
-- in the lower 15 bits, with upper two bits used as a signed bit.
cDataIn : in std_logic_vector(kDataWidth-1 downto 0);
cDataValidIn : in std_logic;
-- [..Q1,I1,Q0,I0] (I in LSBs). 16 bit output with a gain of 2x.
cDataOut : out std_logic_vector(kDataWidth-1 downto 0);
cDataValidOut : out std_logic
);
end scale_2x;
architecture RTL of scale_2x is
begin
-- Scale the date by 2 by shifting the data to the left by 1 bit.
cDataOut <= Gain2x(cDataIn);
cDataValidOut <= cDataValidIn;
end RTL;
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