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authorMatthias P. Braendli <matthias.braendli@mpb.li>2017-11-18 04:06:29 +0100
committerMatthias P. Braendli <matthias.braendli@mpb.li>2017-11-18 04:06:29 +0100
commit6d2083d4b700ef2edc5f4e38d4ecd9df8912a615 (patch)
tree8530ed113aaf741a81a77c59d0511f776bbd1284 /src/TII.cpp
parent40509399e2563798f260863df23ceef89d528c5a (diff)
parent4f2fcae5ad028b76ac1d41a279857df85f20c376 (diff)
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Merge branch 'next' into outputRefactoring
Diffstat (limited to 'src/TII.cpp')
-rw-r--r--src/TII.cpp24
1 files changed, 19 insertions, 5 deletions
diff --git a/src/TII.cpp b/src/TII.cpp
index 8a8bd86..4710ed4 100644
--- a/src/TII.cpp
+++ b/src/TII.cpp
@@ -197,16 +197,30 @@ int TII::process(Buffer* dataIn, Buffer* dataOut)
complexf* in = reinterpret_cast<complexf*>(dataIn->getData());
complexf* out = reinterpret_cast<complexf*>(dataOut->getData());
+ if ((m_enabled_carriers.size() % 2) != 0) {
+ throw std::logic_error("odd number of enabled carriers");
+ }
+
+ /* Normalise the TII carrier power according to ETSI TR 101 496-3
+ * Clause 5.4.2.2 Paragraph 7:
+ *
+ * > The ratio of carriers in a TII symbol to a normal DAB symbol
+ * > is 1:48 for all Modes, so that the signal power in a TII symbol is
+ * > 16 dB below the signal power of the other symbols.
+ *
+ * We need to normalise to the square root of 48 because we touch I and
+ * Q separately.
+ */
+ const float normalise_factor = 0.14433756729740644112f; // = 1/sqrt(48)
+
for (size_t i = 0; i < m_enabled_carriers.size(); i+=2) {
- //BAD implementation:
- // setting exactly the same phase of the signal for lower adjacent
- // frequency
+ // See header file for an explanation of the old variant
if (m_enabled_carriers[i]) {
- out[i] = m_conf.old_variant ? in[i+1] : in[i];
+ out[i] = normalise_factor * (m_conf.old_variant ? in[i+1] : in[i]);
}
if (m_enabled_carriers[i+1]) {
- out[i+1] = in[i+1];
+ out[i+1] = normalise_factor * in[i+1];
}
}
}