From 2278f839699ec2523be5c93d37d1f9497a41b97b Mon Sep 17 00:00:00 2001
From: Eric Kooistra <kooistra@astron.nl>
Date: Thu, 14 Oct 2021 16:56:49 +0200
Subject: [PATCH] Reorganized definition of width, magnitude and fraction for
fixed point weights, no quantitive change.
---
.../sdp/src/vhdl/sdp_beamformer_local.vhd | 2 +-
.../lofar2/libraries/sdp/src/vhdl/sdp_pkg.vhd | 24 ++++++++--------
.../sdp/src/vhdl/sdp_subband_equalizer.vhd | 2 +-
.../model/lofar_station_firmware_model.py | 28 +++++++++----------
4 files changed, 29 insertions(+), 27 deletions(-)
diff --git a/applications/lofar2/libraries/sdp/src/vhdl/sdp_beamformer_local.vhd b/applications/lofar2/libraries/sdp/src/vhdl/sdp_beamformer_local.vhd
index 2f75f2f098..134b80aa33 100644
--- a/applications/lofar2/libraries/sdp/src/vhdl/sdp_beamformer_local.vhd
+++ b/applications/lofar2/libraries/sdp/src/vhdl/sdp_beamformer_local.vhd
@@ -228,7 +228,7 @@ BEGIN
GENERIC MAP (
g_complex => TRUE,
g_representation => "SIGNED",
- g_lsb_w => c_sdp_W_bf_fraction,
+ g_lsb_w => c_sdp_W_bf_weight_fraction,
g_lsb_round => TRUE,
g_lsb_round_clip => FALSE,
g_msb_clip => FALSE,
diff --git a/applications/lofar2/libraries/sdp/src/vhdl/sdp_pkg.vhd b/applications/lofar2/libraries/sdp/src/vhdl/sdp_pkg.vhd
index 547b1301ff..1aa14bfa2e 100644
--- a/applications/lofar2/libraries/sdp/src/vhdl/sdp_pkg.vhd
+++ b/applications/lofar2/libraries/sdp/src/vhdl/sdp_pkg.vhd
@@ -87,27 +87,29 @@ PACKAGE sdp_pkg is
CONSTANT c_sdp_V_si_histogram : NATURAL := 512;
CONSTANT c_sdp_W_adc : NATURAL := 14;
CONSTANT c_sdp_W_adc_jesd : NATURAL := 16;
- CONSTANT c_sdp_W_beamlet : NATURAL := 8;
- CONSTANT c_sdp_W_beamlet_scale : NATURAL := 16;
- CONSTANT c_sdp_W_beamlet_sum : NATURAL := 18;
- CONSTANT c_sdp_W_bf_magnitude : NATURAL := 1;
- CONSTANT c_sdp_W_bf_weight : NATURAL := 16;
- CONSTANT c_sdp_W_crosslet : NATURAL := 16;
CONSTANT c_sdp_W_fir_coef : NATURAL := 16;
+ CONSTANT c_sdp_W_subband : NATURAL := 18;
+ CONSTANT c_sdp_W_crosslet : NATURAL := 16;
+ CONSTANT c_sdp_W_beamlet_sum : NATURAL := 18;
+ CONSTANT c_sdp_W_beamlet : NATURAL := 8;
CONSTANT c_sdp_W_gn_id : NATURAL := 5;
CONSTANT c_sdp_W_statistic : NATURAL := 64;
- CONSTANT c_sdp_W_sub_magnitude : NATURAL := 2;
- CONSTANT c_sdp_W_sub_weight : NATURAL := 16;
- CONSTANT c_sdp_W_subband : NATURAL := 18;
+ CONSTANT c_sdp_W_sub_weight : NATURAL := 16; -- = w in s(w, p), s = signed
+ CONSTANT c_sdp_W_sub_weight_fraction : NATURAL := 13; -- = p in s(w, p)
+ CONSTANT c_sdp_W_sub_weight_magnitude : NATURAL := c_sdp_W_sub_weight - c_sdp_W_sub_weight_fraction - 1; -- = 2
+ CONSTANT c_sdp_W_beamlet_scale : NATURAL := 16; -- = w in u(w, p), u = unsigned
+ CONSTANT c_sdp_W_beamlet_scale_fraction : NATURAL := 15; -- = p in u(w, p)
+ CONSTANT c_sdp_W_beamlet_scale_magnitude : NATURAL := c_sdp_W_beamlet_scale - c_sdp_W_beamlet_scale_fraction; -- = 1
+ CONSTANT c_sdp_W_bf_weight : NATURAL := 16; -- = w in s(w, p), s = signed
+ CONSTANT c_sdp_W_bf_weight_fraction : NATURAL := 14; -- = p in s(w, p)
+ CONSTANT c_sdp_W_bf_weight_magnitude : NATURAL := c_sdp_W_bf_weight - c_sdp_W_bf_weight_fraction - 1; -- = 1
-- Derived constants
CONSTANT c_sdp_FS_adc : NATURAL := 2**(c_sdp_W_adc - 1); -- full scale FS corresponds to amplitude 1.0
CONSTANT c_sdp_P_pfb : NATURAL := c_sdp_S_pn / c_sdp_Q_fft;
CONSTANT c_sdp_T_adc : TIME := (10**6 / c_sdp_f_adc_MHz) * 1 ps;
CONSTANT c_sdp_T_sub : TIME := c_sdp_N_fft * c_sdp_T_adc;
- CONSTANT c_sdp_W_bf_fraction : NATURAL := c_sdp_W_bf_weight - c_sdp_W_bf_magnitude -1;
CONSTANT c_sdp_W_bf_product : NATURAL := c_sdp_W_subband + c_sdp_W_bf_weight -1;
- CONSTANT c_sdp_W_sub_fraction : NATURAL := c_sdp_W_sub_weight - c_sdp_W_sub_magnitude -1;
CONSTANT c_sdp_X_sq : NATURAL := c_sdp_S_pn * c_sdp_S_pn;
--
diff --git a/applications/lofar2/libraries/sdp/src/vhdl/sdp_subband_equalizer.vhd b/applications/lofar2/libraries/sdp/src/vhdl/sdp_subband_equalizer.vhd
index fe03722c40..7ae6012f07 100644
--- a/applications/lofar2/libraries/sdp/src/vhdl/sdp_subband_equalizer.vhd
+++ b/applications/lofar2/libraries/sdp/src/vhdl/sdp_subband_equalizer.vhd
@@ -146,7 +146,7 @@ BEGIN
GENERIC MAP (
g_complex => TRUE,
g_representation => "SIGNED",
- g_lsb_w => c_sdp_W_sub_fraction,
+ g_lsb_w => c_sdp_W_sub_weight_fraction,
g_lsb_round => TRUE,
g_lsb_round_clip => FALSE,
g_msb_clip => TRUE,
diff --git a/applications/lofar2/model/lofar_station_firmware_model.py b/applications/lofar2/model/lofar_station_firmware_model.py
index 11d1ecea59..260a77962c 100644
--- a/applications/lofar2/model/lofar_station_firmware_model.py
+++ b/applications/lofar2/model/lofar_station_firmware_model.py
@@ -148,21 +148,21 @@ N_sub = 512 # = N_fft / N_complex
W_fsub_proc = math.log(math.sqrt(N_sub), 2) # = 4.5, processing gain of F_sub in number of bits
N_int_sub = 195312.5
-W_se_weight = 16
-W_se_magnitude = 1
-W_se_fraction = 14
-c_se_unit_weight = 2**W_se_fraction
-W_bf_weight = 16
-W_bf_magnitude = 1
-W_bf_fraction = 14
-c_bf_unit_weight = 2**W_sub_fraction
+W_sub_weight = 16 # signed
+W_sub_weight_fraction = 13
+W_sub_weight_magnitude = W_sub_weight - W_sub_weight_fraction - 1
+c_sub_weight_unit = 2**W_sub_weight_fraction
-W_beamlet_scale = 16
-W_beamlet_scale_magnitude = 1
-W_beamlet_scale_fraction = 14
-c_beamlet_scale_unit = 2**W_beamlet_scale_fraction
+W_bf_weight = 16 # signed
+W_bf_weight_fraction = 14
+W_bf_weight_magnitude = W_bf_weight - W_bf_weight_fraction - 1
+c_bf_weight_unit = 2**W_bf_weight_fraction
+W_beamlet_scale = 16 # unsigned
+W_beamlet_scale_fraction = 15
+W_beamlet_scale_magnitude = W_beamlet_scale - W_beamlet_scale_fraction
+c_beamlet_scale_unit = 2**W_beamlet_scale_fraction
W_sst_fraction = 4 # Extra fraction bits for SST subband input compared to W_adc
W_sst_in = 18 # Word width in number of bits of SST subband data input, = W_adc + W_sst_fraction
@@ -312,8 +312,8 @@ if 'dynamic' in models:
# Derived gains
# Aperif BF subband CB voltage weight
-subWeight = c_sub_unit_weight * subWeightAdjust # = 16384 = 2**14 * 1.0
-bfWeight = c_bf_unit_weight * bfWeightAdjust # = 16384 = 2**14 * 1.0
+subWeight = c_sub_weight_unit * subWeightAdjust # = 16384 = 2**14 * 1.0
+bfWeight = c_bf_weight_unit * bfWeightAdjust # = 16384 = 2**14 * 1.0
if quantize:
subWeight = np.round(subWeight)
bfWeight = np.round(bfWeight)
--
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