firinterp.v

一种基于LUT的预失真方法。其中的一部分

//16倍插值Fir滤波

module FIRInterp(RST,sysclk,DInEn,LDin,RDin,DOutEn,LDout,RDout);
parameter IO_WIDTH=16;

input RST,sysclk,DInEn;
input signed[IO_WIDTH-1:0] LDin,RDin;
output DOutEn;
output signed[IO_WIDTH-1:0] LDout,RDout;

reg signed[IO_WIDTH-1:0] RDout,LDout;
reg DOutEn;

reg[IO_WIDTH*2-1:0] mem[15:0];
reg[IO_WIDTH*2-1:0] d,q;
reg[3:0] a;
reg we;
reg signed[IO_WIDTH-1:0] Md;
reg signed[17:0] Rcof;
wire[17:0] wcof;
wire signed[IO_WIDTH+17:0] MultR;
reg signed[IO_WIDTH+17:0] LTDt,RTDt;
//integer m;

reg[8:0] TapCnt;
reg[7:0] RomAdd;

assign MultR=Md*Rcof;

always@(posedge sysclk or posedge RST) begin
	if(RST) begin
		LTDt<=0;RTDt<=0;RDout<=0;LDout<=0;
		TapCnt<=9'h0;RomAdd<=8'h0;DOutEn<=1'b0;a<=4'h0;d<=0;Md<=0;Rcof<=18'h0;
	end
	else begin
		Rcof<=wcof;
		if(TapCnt[0])
			Md<=q[IO_WIDTH*2-1:IO_WIDTH];
		else
			Md<=q[IO_WIDTH-1: 0];
		if(TapCnt[4:0]==5'h3) begin
			RTDt<=MultR;
			LDout<=LTDt[IO_WIDTH+16:17];
			RDout<=RTDt[IO_WIDTH+16:17];
			DOutEn<=1'b1;
		end
		else if(TapCnt[4:0]==5'h4) begin
			LTDt<=MultR;	
			DOutEn<=1'b0;
		end
		else begin 
			DOutEn<=1'b0;
			if(TapCnt[0])
				RTDt<=RTDt+MultR;
			else 
				LTDt<=LTDt+MultR;
		end
		if((DInEn)) begin
			TapCnt<=9'h1e2;
			d[IO_WIDTH*2-1:IO_WIDTH]<=LDin;
			d[IO_WIDTH-1: 0]<=RDin;
			we<=1'b1;
		end
		else begin
			TapCnt<=TapCnt+9'd1;
			we<=1'b0;
		end
		if(TapCnt==9'h0) begin
			a<=a+4'h2;
		end 
		else if(TapCnt[0]==0)begin
			a<=a+4'h1;
		end
		RomAdd<={TapCnt[4:1],~TapCnt[8:5]};
	end
end
MyCofRom CofTab(.clk(sysclk),.Address(RomAdd),.Data(wcof));

//always @ (posedge sysclk or posedge RST) begin //data ram
/*	if(RST) begin
	    for(m=0;m<16;m=m+1) begin
	        mem[m]<=0;
	    end
	    q<=0;
	end
	else begin*/
always @ (posedge sysclk) begin //data ram
	   if (we)
		   mem[a] <= d;
	   q <= mem[a]; // q doesn't get d in this clock cycle
//	end
end

endmodule