From b0e5a7862827666e8cbd8599384000634d6b91e3 Mon Sep 17 00:00:00 2001
From: Eric Kooistra <kooistra@astron.nl>
Date: Thu, 22 Sep 2022 14:09:15 +0200
Subject: [PATCH] Notes for LIFT project SDPFW design.

---
 .../station2_sdp_transient_buffer.txt         | 19 +++++++++++++++++++
 1 file changed, 19 insertions(+)
 create mode 100644 applications/lofar2/doc/prestudy/station2_sdp_transient_buffer.txt

diff --git a/applications/lofar2/doc/prestudy/station2_sdp_transient_buffer.txt b/applications/lofar2/doc/prestudy/station2_sdp_transient_buffer.txt
new file mode 100644
index 0000000000..cc8af7d4b1
--- /dev/null
+++ b/applications/lofar2/doc/prestudy/station2_sdp_transient_buffer.txt
@@ -0,0 +1,19 @@
+Detailed design: Transient Buffer function (LIFT)
+
+
+1) DDR4 memory per receiver input
+
+Bottom up:
+
+Per FPGA there are S_pn = 12 receiver inputs.
+Per FPGA there are N_ddr = 2 DDR4 modules of V_ddr = 8 GByte each.
+==> Per recveiver input N_ddr * V_ddr / S_pn = 1.33 GByte.
+The receiver input data rate is f_adc = 200 MHz and sample width is W_adc = 14 b.
+Assume the samples are stored in 16 b (= 2 bytes), this creates 16/14 = 14 % storage overhead
+Assume 4 % storage overhead for packet header information
+==> Per recveiver input T_tbuf = 1.33 GByte / (2 byte/sample) / 1.04 / f_adc = 3.2 sec maximum storage time.
+==> 192 * 1.33 = 256 GByte / LB for T_tbuf = 3.2 s
+
+Hoe streng is de 3.33 s, mag 3.2 s ook ?
+Moeten we nog grotere 16 GByte modules gaan aanschaffen en te testen met unb2c, zodat we 2x zoveel storage tijd hebben ?
+
-- 
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