module douki_tx_rx(clk,indata,sin,douki,freq_mod);
input clk;
input signed [15:0] indata;
input signed [15:0] sin;
input douki;
output [31:0] freq_mod;


reg signed [31:0] multi;

always@(posedge clk)begin
	multi <= indata*sin/4096;
end


// Vo=integ(Vi-Vo/CR)
reg signed [31:0] freq_mod_offset;
reg signed [31:0] freq_mod;
always@(posedge clk)begin
	if(douki==1)
		freq_mod_offset <= freq_mod_offset + (multi-freq_mod_offset)/256;
	else
		freq_mod_offset <= freq_mod_offset;		
end

always@(posedge clk)begin
	freq_mod <= 582542222+freq_mod_offset;		
end



endmodule