From 51c504ebb1ca21c5f7071826c1af03e45e391a65 Mon Sep 17 00:00:00 2001
From: Daniel Estévez <daniel@destevez.net>
Date: Sun, 6 Jun 2021 11:25:57 +0200
Subject: digital: Add NRZI option to differential en/decoder
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This adds an option to the differential encoder an decoder blocks
to perform NRZI encoding and decoding. NRZI only makes sense with
a modulus of 2, so the blocks constructors will throw and exception
if passed nrzi = true and a modulus different from 2.
The GRC blocks handle this by hiding the modulus field if the user
selects NRZI encoding.
A new unit test for the NRZI version of the blocks is added. Besides
checking that encode plus decode gives the original, this test also
compares the C++ implementation results against a Numpy implementation.
Additionally, a faster implementation of differential encoding/
decoding for modulus 2 is included here.
Signed-off-by: Daniel Estévez <daniel@destevez.net>
---
gr-digital/lib/diff_decoder_bb_impl.h | 7 +++++--
1 file changed, 5 insertions(+), 2 deletions(-)
(limited to 'gr-digital/lib/diff_decoder_bb_impl.h')
diff --git a/gr-digital/lib/diff_decoder_bb_impl.h b/gr-digital/lib/diff_decoder_bb_impl.h
index 10688f427f..d73a5fe7b9 100644
--- a/gr-digital/lib/diff_decoder_bb_impl.h
+++ b/gr-digital/lib/diff_decoder_bb_impl.h
@@ -1,6 +1,7 @@
/* -*- c++ -*- */
/*
* Copyright 2006,2012 Free Software Foundation, Inc.
+ * Copyright 2021 Daniel Estevez <daniel@destevez.net>
*
* This file is part of GNU Radio
*
@@ -20,7 +21,8 @@ namespace digital {
class diff_decoder_bb_impl : public diff_decoder_bb
{
public:
- diff_decoder_bb_impl(unsigned int modulus);
+ diff_decoder_bb_impl(unsigned int modulus,
+ enum diff_coding_type coding = DIFF_DIFFERENTIAL);
~diff_decoder_bb_impl() override;
int work(int noutput_items,
@@ -28,7 +30,8 @@ public:
gr_vector_void_star& output_items) override;
private:
- unsigned int d_modulus;
+ const unsigned int d_modulus;
+ const enum diff_coding_type d_coding;
};
} /* namespace digital */
--
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