From 8bb7afbdc7cab7010c5bfb5a0b750a62d953aedf Mon Sep 17 00:00:00 2001 From: "Matthias P. Braendli" Date: Thu, 4 May 2023 13:27:10 +0200 Subject: Revert "Normalise TII to 1/sqrt(48)" and fix TII level in GainControl This reverts commit c7961c2e8688d6db2a87b5079c60a04b8fe37e74. --- src/GainControl.cpp | 23 ++++++++++++++++------- src/GainControl.h | 1 + src/TII.cpp | 9 ++++----- 3 files changed, 21 insertions(+), 12 deletions(-) diff --git a/src/GainControl.cpp b/src/GainControl.cpp index c111de3..d90da45 100644 --- a/src/GainControl.cpp +++ b/src/GainControl.cpp @@ -127,21 +127,25 @@ int GainControl::internal_process(Buffer* const dataIn, Buffer* dataOut) if ((sizeIn % m_frameSize) != 0) { PDEBUG("%zu != %zu\n", sizeIn, m_frameSize); - throw std::runtime_error( - "GainControl::process input size not valid!"); + throw std::runtime_error("GainControl::process input size not valid!"); } const auto constantGain4 = _mm_set1_ps(constantGain); for (size_t i = 0; i < sizeIn; i += m_frameSize) { - gain128.m = computeGain(in, m_frameSize); + // Do not apply gain computation to the NULL symbol, which either + // is blank or contains TII. Apply the gain calculation from the next + // symbol on the NULL symbol to get consistent TII power. + if (i > 0) { + gain128.m = computeGain(in, m_frameSize); + } + else { + gain128.m = computeGain(in + m_frameSize, m_frameSize); + } gain128.m = _mm_mul_ps(gain128.m, constantGain4); PDEBUG("********** Gain: %10f **********\n", gain128.f[0]); - //////////////////////////////////////////////////////////////////////// - // Applying gain to output data - //////////////////////////////////////////////////////////////////////// for (size_t sample = 0; sample < m_frameSize; ++sample) { out[sample] = _mm_mul_ps(in[sample], gain128.m); } @@ -163,7 +167,12 @@ int GainControl::internal_process(Buffer* const dataIn, Buffer* dataOut) } for (size_t i = 0; i < sizeIn; i += m_frameSize) { - gain = constantGain * computeGain(in, m_frameSize); + // Do not apply gain computation to the NULL symbol, which either + // is blank or contains TII. Apply the gain calculation from the next + // symbol on the NULL symbol to get consistent TII power. + gain = constantGain * (i > 0 ? + computeGain(in, m_frameSize) : + computeGain(in + m_frameSize, m_frameSize)); PDEBUG("********** Gain: %10f **********\n", gain); diff --git a/src/GainControl.h b/src/GainControl.h index f0fd6b6..f024fa2 100644 --- a/src/GainControl.h +++ b/src/GainControl.h @@ -38,6 +38,7 @@ #include #include #include + #ifdef __SSE__ # include #endif diff --git a/src/TII.cpp b/src/TII.cpp index 2d7429f..b329cdb 100644 --- a/src/TII.cpp +++ b/src/TII.cpp @@ -189,8 +189,6 @@ int TII::process(Buffer* dataIn, Buffer* dataOut) complexf* in = reinterpret_cast(dataIn->getData()); complexf* out = reinterpret_cast(dataOut->getData()); - constexpr float normalisation = 0.144337f; // 1/sqrt(48); - /* Normalise the TII carrier power according to ETSI TR 101 496-3 * Clause 5.4.2.2 Paragraph 7: * @@ -198,7 +196,8 @@ int TII::process(Buffer* dataIn, Buffer* dataOut) * > 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. * - * Divide by sqrt(48) because I and Q are separately normalised. + * This is because we only enable 32 out of 1536 carriers, not because + * every carrier is lower power. */ for (size_t i = 0; i < m_Acp.size(); i++) { /* See header file for an explanation of the old variant. @@ -219,8 +218,8 @@ int TII::process(Buffer* dataIn, Buffer* dataOut) * and fuse the two conditionals together: */ if (m_Acp[i]) { - out[i] = in[i] * normalisation; - out[i+1] = (m_conf.old_variant ? in[i+1] : in[i]) * normalisation; + out[i] = in[i]; + out[i+1] = (m_conf.old_variant ? in[i+1] : in[i]); } } } -- cgit v1.2.3