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//
// Copyright 2015 Ettus Research LLC
// Copyright 2018 Ettus Research, a National Instruments Company
//
// SPDX-License-Identifier: LGPL-3.0-or-later
//
module rx_dcoffset
#(parameter WIDTH=16,
parameter ADDR=8'd0,
parameter alpha_shift=20)
(input clk, input rst,
input set_stb, input [7:0] set_addr, input [31:0] set_data,
input in_stb, input [WIDTH-1:0] in,
output out_stb, output [WIDTH-1:0] out);
wire set_now = set_stb & (ADDR == set_addr);
reg fixed; // uses fixed offset
wire [WIDTH-1:0] fixed_dco;
localparam int_width = WIDTH + alpha_shift;
reg [int_width-1:0] integrator;
reg integ_in_stb;
wire [WIDTH-1:0] quantized;
always @(posedge clk) begin
if(rst)
begin
integ_in_stb <= 0;
fixed <= 0;
integrator <= {int_width{1'b0}};
end
else if(set_now)
begin
fixed <= set_data[31];
if(set_data[30])
integrator <= {set_data[29:0],{(int_width-30){1'b0}}};
end
else if(~fixed & in_stb)
integrator <= integrator + {{(alpha_shift){out[WIDTH-1]}},out};
integ_in_stb <= in_stb;
end
round_sd #(.WIDTH_IN(int_width),.WIDTH_OUT(WIDTH)) round_sd
(.clk(clk), .reset(rst), .in(integrator), .strobe_in(integ_in_stb), .out(quantized), .strobe_out());
add2_and_clip_reg #(.WIDTH(WIDTH)) add2_and_clip_reg
(.clk(clk), .rst(rst), .in1(in), .in2(-quantized), .strobe_in(in_stb), .sum(out), .strobe_out(out_stb));
endmodule // rx_dcoffset
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