diff options
| -rw-r--r-- | usrp2/sdr_lib/small_hb_dec.v | 10 |
1 files changed, 6 insertions, 4 deletions
diff --git a/usrp2/sdr_lib/small_hb_dec.v b/usrp2/sdr_lib/small_hb_dec.v index a7f93e056..c05a48b81 100644 --- a/usrp2/sdr_lib/small_hb_dec.v +++ b/usrp2/sdr_lib/small_hb_dec.v @@ -103,22 +103,24 @@ module small_hb_dec wire [17:0] coeff = go_d1 ? coeff_b : coeff_a; wire [35:0] prod; MULT18X18S mult(.C(clk), .CE(go_d1 | go_d2), .R(rst), .P(prod), .A(coeff), .B(sum) ); + + localparam ACCWIDTH = 30; + reg [ACCWIDTH-1:0] accum; - reg [35:0] accum; always @(posedge clk) if(rst) accum <= 0; else if(go_d2) - accum <= {middle_d1[17],middle_d1[17],middle_d1,16'd0} + {prod}; + accum <= {middle_d1[17],middle_d1[17],middle_d1,{(16+ACCWIDTH-36){1'b0}}} + {prod[35:36-ACCWIDTH]}; else if(go_d3) - accum <= accum + {prod}; + accum <= accum + {prod[35:36-ACCWIDTH]}; wire [WIDTH:0] accum_rnd; wire [WIDTH-1:0] accum_rnd_clip; wire stb_round; - round_sd #(.WIDTH_IN(36),.WIDTH_OUT(WIDTH+1)) round_acc + round_sd #(.WIDTH_IN(ACCWIDTH),.WIDTH_OUT(WIDTH+1)) round_acc (.clk(clk), .reset(rst), .in(accum), .strobe_in(go_d4), .out(accum_rnd), .strobe_out(stb_round)); clip #(.bits_in(WIDTH+1),.bits_out(WIDTH)) clip (.in(accum_rnd), .out(accum_rnd_clip)); |