From fc037c739a7c4d6abed23f2a5aaf977d2dfdf2f7 Mon Sep 17 00:00:00 2001 From: Jared Boone Date: Sat, 7 Nov 2015 11:27:31 -0800 Subject: [PATCH] Comment about correct MatchedFilter usage. Because the filter expects a combined translate/rotate and low-pass filter in the taps, the taps must be a multiple of the translate sinusoid period. --- firmware/baseband/matched_filter.hpp | 5 +++++ 1 file changed, 5 insertions(+) diff --git a/firmware/baseband/matched_filter.hpp b/firmware/baseband/matched_filter.hpp index a1547901..b33d7a9a 100644 --- a/firmware/baseband/matched_filter.hpp +++ b/firmware/baseband/matched_filter.hpp @@ -36,6 +36,11 @@ namespace dsp { namespace matched_filter { +// This filter contains "magic" (optimizations) that expect the taps to +// combine a low-pass filter with a complex sinusoid that performs shifting of +// the input signal to 0Hz/DC. This also means that the taps length must be +// a multiple of the complex sinusoid period. + class MatchedFilter { public: using sample_t = std::complex;