module AD6645 ( input clk_in, input rst_n, input [13:0] AD_data, output [13:0] wave_CH ); reg [13:0] wave_CH_buf; always@(posedge clk_in or negedge rst_n) begin if(!rst_n) wave_CH_buf <= 14'd0; else wave_CH_buf <= AD_data; end assign wave_CH = wave_CH_buf - 14'd1700; endmodule