Added basic RDS support, no error correction yet

core/src/dsp/clock_recovery/fd.h

@@ -0,0 +1,189 @@
+#pragma once
+#include "../processor.h"
+#include "../loop/phase_control_loop.h"
+#include "../taps/windowed_sinc.h"
+#include "../multirate/polyphase_bank.h"
+#include "../math/step.h"
+
+namespace dsp::clock_recovery {
+    class FD : public Processor<float, float> {
+        using base_type = Processor<float, float> ;
+    public:
+        FD() {}
+
+        FD(stream<float>* in, double omega, double omegaGain, double muGain, double omegaRelLimit, int interpPhaseCount = 128, int interpTapCount = 8) { init(in, omega, omegaGain, muGain, omegaRelLimit, interpPhaseCount, interpTapCount); }
+
+        ~FD() {
+            if (!base_type::_block_init) { return; }
+            base_type::stop();
+            dsp::multirate::freePolyphaseBank(interpBank);
+            buffer::free(buffer);
+        }
+
+        void init(stream<float>* in, double omega, double omegaGain, double muGain, double omegaRelLimit, int interpPhaseCount = 128, int interpTapCount = 8) {
+            _omega = omega;
+            _omegaGain = omegaGain;
+            _muGain = muGain;
+            _omegaRelLimit = omegaRelLimit;
+            _interpPhaseCount = interpPhaseCount;
+            _interpTapCount = interpTapCount;
+
+            pcl.init(_muGain, _omegaGain, 0.0, 0.0, 1.0, _omega, _omega * (1.0 - omegaRelLimit), _omega * (1.0 + omegaRelLimit));
+            generateInterpTaps();
+            buffer = buffer::alloc<float>(STREAM_BUFFER_SIZE + _interpTapCount);
+            bufStart = &buffer[_interpTapCount - 1];
+        
+            base_type::init(in);
+        }
+
+        void setOmega(double omega) {
+            assert(base_type::_block_init);
+            std::lock_guard<std::recursive_mutex> lck(base_type::ctrlMtx);
+            base_type::tempStop();
+            _omega = omega;
+            offset = 0;
+            pcl.phase = 0.0f;
+            pcl.freq = _omega;
+            pcl.setFreqLimits(_omega * (1.0 - _omegaRelLimit), _omega * (1.0 + _omegaRelLimit));
+            base_type::tempStart();
+        }
+
+        void setOmegaGain(double omegaGain) {
+            assert(base_type::_block_init);
+            std::lock_guard<std::recursive_mutex> lck(base_type::ctrlMtx);
+            _omegaGain = omegaGain;
+            pcl.setCoefficients(_muGain, _omegaGain);
+        }
+
+        void setMuGain(double muGain) {
+            assert(base_type::_block_init);
+            std::lock_guard<std::recursive_mutex> lck(base_type::ctrlMtx);
+            _muGain = muGain;
+            pcl.setCoefficients(_muGain, _omegaGain);
+        }
+
+        void setOmegaRelLimit(double omegaRelLimit) {
+            assert(base_type::_block_init);
+            std::lock_guard<std::recursive_mutex> lck(base_type::ctrlMtx);
+            _omegaRelLimit = omegaRelLimit;
+            pcl.setFreqLimits(_omega * (1.0 - _omegaRelLimit), _omega * (1.0 + _omegaRelLimit));
+        }
+
+        void setInterpParams(int interpPhaseCount, int interpTapCount) {
+            assert(base_type::_block_init);
+            std::lock_guard<std::recursive_mutex> lck(base_type::ctrlMtx);
+            base_type::tempStop();
+            _interpPhaseCount = interpPhaseCount;
+            _interpTapCount = interpTapCount;
+            dsp::multirate::freePolyphaseBank(interpBank);
+            buffer::free(buffer);
+            generateInterpTaps();
+            buffer = buffer::alloc<float>(STREAM_BUFFER_SIZE + _interpTapCount);
+            bufStart = &buffer[_interpTapCount - 1];
+            base_type::tempStart();
+        }
+
+        void reset() {
+            assert(base_type::_block_init);
+            std::lock_guard<std::recursive_mutex> lck(base_type::ctrlMtx);
+            base_type::tempStop();
+            offset = 0;
+            pcl.phase = 0.0f;
+            pcl.freq = _omega;
+            base_type::tempStart();
+        }
+
+        inline int process(int count, const float* in, float* out) {
+            // Copy data to work buffer
+            memcpy(bufStart, in, count * sizeof(float));
+
+            // Process all samples
+            int outCount = 0;
+            while (offset < count) {
+                float error;
+                float outVal;
+                float dfdt;
+
+                // Calculate new output value
+                int phase = std::clamp<int>(floorf(pcl.phase * (float)_interpPhaseCount), 0, _interpPhaseCount - 1);
+                volk_32f_x2_dot_prod_32f(&outVal, &buffer[offset], interpBank.phases[phase], _interpTapCount);
+                out[outCount++] = outVal;
+
+                // Calculate derivative of the signal
+                if (phase == 0) {
+                    float fT1;
+                    volk_32f_x2_dot_prod_32f(&fT1, &buffer[offset], interpBank.phases[phase+1], _interpTapCount);
+                    dfdt = fT1 - outVal;
+                }
+                else if (phase == _interpPhaseCount - 1) {
+                    float fT_1;
+                    volk_32f_x2_dot_prod_32f(&fT_1, &buffer[offset], interpBank.phases[phase-1], _interpTapCount);
+                    dfdt = outVal - fT_1;
+                }
+                else {
+                    float fT_1;
+                    float fT1;
+                    volk_32f_x2_dot_prod_32f(&fT_1, &buffer[offset], interpBank.phases[phase-1], _interpTapCount);
+                    volk_32f_x2_dot_prod_32f(&fT1, &buffer[offset], interpBank.phases[phase+1], _interpTapCount);
+                    dfdt = (fT1 - fT_1) * 0.5f;
+                }
+                
+                // Calculate error
+                error = dfdt * math::step(outVal);
+
+                // Clamp symbol phase error
+                if (error > 1.0f) { error = 1.0f; }
+                if (error < -1.0f) { error = -1.0f; }
+
+                // Advance symbol offset and phase
+                pcl.advance(error);
+                float delta = floorf(pcl.phase);
+                offset += delta;
+                pcl.phase -= delta;
+            }
+            offset -= count;
+
+            // Update delay buffer
+            memmove(buffer, &buffer[count], (_interpTapCount - 1) * sizeof(float));
+
+            return outCount;
+        }
+
+        int run() {
+            int count = base_type::_in->read();
+            if (count < 0) { return -1; }
+
+            int outCount = process(count, base_type::_in->readBuf, base_type::out.writeBuf);
+
+            // Swap if some data was generated
+            base_type::_in->flush();
+            if (outCount) {
+                if (!base_type::out.swap(outCount)) { return -1; }
+            }
+            return outCount;
+        }
+
+        loop::PhaseControlLoop<float, false> pcl;
+
+    protected:
+        void generateInterpTaps() {
+            double bw = 0.5 / (double)_interpPhaseCount;
+            dsp::tap<float> lp = dsp::taps::windowedSinc<float>(_interpPhaseCount * _interpTapCount, dsp::math::freqToOmega(bw, 1.0), dsp::window::nuttall, _interpPhaseCount);
+            interpBank = dsp::multirate::buildPolyphaseBank<float>(_interpPhaseCount, lp);
+            taps::free(lp);
+        }
+
+        dsp::multirate::PolyphaseBank<float> interpBank;
+
+        double _omega;
+        double _omegaGain;
+        double _muGain;
+        double _omegaRelLimit;
+        int _interpPhaseCount;
+        int _interpTapCount;
+
+        int offset = 0;
+        float* buffer;
+        float* bufStart;
+    };
+}

core/src/dsp/clock_recovery/mm.h

@@ -178,7 +178,7 @@ namespace dsp::clock_recovery {
         }
 
         dsp::multirate::PolyphaseBank<float> interpBank;
-        loop::PhaseControlLoop<double, false> pcl;
+        loop::PhaseControlLoop<float, false> pcl;
 
         double _omega;
         double _omegaGain;