feat: integrate RTL-TCP server support

2025-11-01 22:39:52 +08:00
parent 356738ac10
commit 5aa19ada14
379 changed files with 109413 additions and 47 deletions
--- a/android/app/src/main/cpp/dsp/costasloop.cpp
+++ b/android/app/src/main/cpp/dsp/costasloop.cpp
@@ -0,0 +1,112 @@
+///////////////////////////////////////////////////////////////////////////////////
+// Copyright (C) 2021 Jon Beniston, M7RCE <jon@beniston.com>                     //
+// Copyright 2006-2021 Free Software Foundation, Inc.                            //
+// Copyright (C) 2018 Edouard Griffiths, F4EXB                                   //
+//                                                                               //
+// Based on the Costas Loop from GNU Radio                                       //
+//                                                                               //
+// This program is free software; you can redistribute it and/or modify          //
+// it under the terms of the GNU General Public License as published by          //
+// the Free Software Foundation as version 3 of the License, or                  //
+// (at your option) any later version.                                           //
+//                                                                               //
+// This program is distributed in the hope that it will be useful,               //
+// but WITHOUT ANY WARRANTY; without even the implied warranty of                //
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the                  //
+// GNU General Public License V3 for more details.                               //
+//                                                                               //
+// You should have received a copy of the GNU General Public License             //
+// along with this program. If not, see <http://www.gnu.org/licenses/>.          //
+///////////////////////////////////////////////////////////////////////////////////
+
+#include "costasloop.h"
+#include <cmath>
+
+// Loop bandwidth supposedly ~ 2pi/100 rads/sample
+// pskOrder 2, 4 or 8
+CostasLoop::CostasLoop(float loopBW, unsigned int pskOrder) :
+    m_maxFreq(1.0f),
+    m_minFreq(-1.0f),
+    m_pskOrder(pskOrder)
+{
+    computeCoefficients(loopBW);
+    reset();
+}
+
+CostasLoop::~CostasLoop()
+{
+}
+
+void CostasLoop::reset()
+{
+    m_y.real(1.0f);
+    m_y.imag(0.0f);
+    m_freq = 0.0f;
+    m_phase = 0.0f;
+    m_freq = 0.0f;
+    m_error = 0.0f;
+}
+
+// 2nd order loop with critical damping
+void CostasLoop::computeCoefficients(float loopBW)
+{
+    float damping = sqrtf(2.0f) / 2.0f;
+    float denom = (1.0 + 2.0 * damping * loopBW + loopBW * loopBW);
+    m_alpha = (4 * damping * loopBW) / denom;
+    m_beta = (4 * loopBW * loopBW) / denom;
+}
+
+void CostasLoop::setSampleRate(unsigned int sampleRate)
+{
+    (void) sampleRate;
+
+    reset();
+}
+
+static float branchlessClip(float x, float clip)
+{
+    return 0.5f * (std::abs(x + clip) - std::abs(x - clip));
+}
+
+// Don't use built-in complex.h multiply to avoid NaN/INF checking
+static void fastComplexMultiply(std::complex<float> &out, const std::complex<float> cc1, const std::complex<float> cc2)
+{
+    float o_r, o_i;
+
+    o_r = (cc1.real() * cc2.real()) - (cc1.imag() * cc2.imag());
+    o_i = (cc1.real() * cc2.imag()) + (cc1.imag() * cc2.real());
+
+    out.real(o_r);
+    out.imag(o_i);
+}
+
+void CostasLoop::feed(float re, float im)
+{
+    std::complex<float> nco(::cosf(-m_phase), ::sinf(-m_phase));
+
+    std::complex<float> in, out;
+    in.real(re);
+    in.imag(im);
+    fastComplexMultiply(out, in, nco);
+
+    switch (m_pskOrder)
+    {
+    case 2:
+        m_error = phaseDetector2(out);
+        break;
+    case 4:
+        m_error = phaseDetector4(out);
+        break;
+    case 8:
+        m_error = phaseDetector8(out);
+        break;
+    }
+    m_error = branchlessClip(m_error, 1.0f);
+
+    advanceLoop(m_error);
+    phaseWrap();
+    frequencyLimit();
+
+    m_y.real(-nco.real());
+    m_y.imag(nco.imag());
+}