diff --git a/libraries/dsp/fft/src/vhdl/fft_r2_pipe.vhd b/libraries/dsp/fft/src/vhdl/fft_r2_pipe.vhd
index 38b199384cd40c7f3b028b249365dc91b3be08ec..fdf43ef38abef91ed6d8b85a8392eaf222ded968 100644
--- a/libraries/dsp/fft/src/vhdl/fft_r2_pipe.vhd
+++ b/libraries/dsp/fft/src/vhdl/fft_r2_pipe.vhd
@@ -63,8 +63,7 @@ entity fft_r2_pipe is
g_pipeline : t_fft_pipeline := c_fft_pipeline; -- generics for pipelining in each stage, defined in rTwoSDF_lib.rTwoSDFPkg
g_dont_flip_channels : boolean := false; -- generic to prevent re-ordering of the channels
g_r2_mul_extra_w : natural := 0; -- extra bits at rTwoWMul output in rTwoSDFStage to improve rTwoSDFStage output requantization
- g_sepa_extra_w : natural := 0; -- extra LSbits in output of last rTwoSDFStage to improve two real separate requantization
- g_sepa_switch_en : boolean := false -- when true apply switch/unswitch to two real inputs to mitigate quantization crosstalk
+ g_sepa_extra_w : natural := 0 -- extra LSbits in output of last rTwoSDFStage to improve two real separate requantization
);
port (
clk : in std_logic;
@@ -82,22 +81,28 @@ architecture str of fft_r2_pipe is
constant c_pipeline_remove_lsb : natural := 0;
+ constant c_switch_en : boolean := g_fft.use_separate; -- default do apply switch/unswitch per real input to mitigate quantization crosstalk
+ constant c_switch_sz_w : natural := ceil_log2(g_fft.nof_points) + g_fft.nof_chan;
+ constant c_switch_dat_w : natural := g_fft.in_dat_w + 1; -- add 1 extra bit to fit negation of most negative value per real input switch function
+ constant c_unswitch_dat_w : natural := g_fft.out_dat_w; -- no need for extra bit, because most negative value cannot occur in output
constant c_nof_stages : natural := ceil_log2(g_fft.nof_points);
constant c_stage_offset : natural := true_log2(g_fft.wb_factor); -- Stage offset is required for twiddle generation in wideband fft
constant c_in_scale_w : natural := g_fft.stage_dat_w - g_fft.in_dat_w - sel_a_b(g_fft.guard_enable, g_fft.guard_w, 0);
constant c_out_scale_w : integer := g_fft.stage_dat_w - g_fft.out_dat_w - g_fft.out_gain_w; -- Estimate number of LSBs to throw throw away when > 0 or insert when < 0
constant c_raw_dat_extra_w : natural := sel_a_b(g_fft.use_separate, g_sepa_extra_w, 0);
constant c_raw_dat_w : natural := g_fft.stage_dat_w + c_raw_dat_extra_w;
- constant c_sepa_mitigate : std_logic := sel_a_b(g_fft.use_separate, '1', '0'); -- apply switch/unswitch to two real inputs to mitigate quantization crosstalk
- constant c_switch_en : std_logic := sel_a_b(g_sepa_switch_en, c_sepa_mitigate, '0');
-- number the stage instances from c_nof_stages:1
-- . the data input for the first stage has index c_nof_stages
-- . the data output of the last stage has index 0
type t_data_arr is array(c_nof_stages downto 0) of std_logic_vector(g_fft.stage_dat_w-1 downto 0);
- signal switch_re : std_logic_vector(g_fft.in_dat_w-1 downto 0);
- signal switch_im : std_logic_vector(g_fft.in_dat_w-1 downto 0);
+ signal in_dat_re : std_logic_vector(c_switch_dat_w-1 downto 0);
+ signal in_dat_im : std_logic_vector(c_switch_dat_w-1 downto 0);
+ signal in_dat_val : std_logic;
+
+ signal switch_re : std_logic_vector(c_switch_dat_w-1 downto 0);
+ signal switch_im : std_logic_vector(c_switch_dat_w-1 downto 0);
signal switch_val : std_logic;
signal data_re : t_data_arr;
@@ -123,16 +128,21 @@ begin
-- the inputs per lock in a random pattern, when g_fft.use_separate = TRUE.
------------------------------------------------------------------------------
+ -- Inputs
+ in_dat_re <= RESIZE_SVEC(in_re, c_switch_dat_w);
+ in_dat_im <= RESIZE_SVEC(in_im, c_switch_dat_w);
+ in_dat_val <= in_val;
+
u_switch : ENTITY work.fft_switch
GENERIC MAP (
- g_fft_sz_w => ceil_log2(g_fft.nof_points),
- g_dat_w => g_fft.in_dat_w
+ g_switch_en => c_switch_en,
+ g_fft_sz_w => c_switch_sz_w,
+ g_dat_w => c_switch_dat_w
)
PORT MAP (
- in_re => in_re,
- in_im => in_im,
- in_val => in_val,
- switch_en => c_switch_en,
+ in_re => in_dat_re,
+ in_im => in_dat_im,
+ in_val => in_dat_val,
out_re => switch_re,
out_im => switch_im,
out_val => switch_val,
@@ -140,7 +150,6 @@ begin
rst => rst
);
- -- Inputs
data_re( c_nof_stages) <= scale_and_resize_svec(switch_re, c_in_scale_w, g_fft.stage_dat_w);
data_im( c_nof_stages) <= scale_and_resize_svec(switch_im, c_in_scale_w, g_fft.stage_dat_w);
data_val(c_nof_stages) <= switch_val;
@@ -188,12 +197,11 @@ begin
in_re => data_re(1),
in_im => data_im(1),
in_val => data_val(1),
- out_re => last_re,
- out_im => last_im,
+ out_re => last_re, -- = data_re(0), but may instead have c_raw_dat_w bits
+ out_im => last_im, -- = data_im(0), but may instead have c_raw_dat_w bits
out_val => data_val(0)
);
-
------------------------------------------------------------------------------
-- Optional output reorder and separation
------------------------------------------------------------------------------
@@ -287,14 +295,14 @@ begin
-- Undo input random negation of u_switch at output when g_fft.use_separate = TRUE
u_unswitch : ENTITY work.fft_unswitch
GENERIC MAP (
- g_fft_sz_w => ceil_log2(g_fft.nof_points),
- g_dat_w => g_fft.out_dat_w
+ g_switch_en => c_switch_en,
+ g_fft_sz_w => c_switch_sz_w,
+ g_dat_w => c_unswitch_dat_w
)
PORT MAP (
in_re => quant_re,
in_im => quant_im,
in_val => quant_val,
- switch_en => c_switch_en,
out_re => out_re,
out_im => out_im,
out_val => out_val,