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/* radioModulatedGenerator_F32.cpp
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* |
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* RadioModulatedGenerator_F32 class - See .h file for information. |
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* Copyright (c) 2021 Bob Larkin Created: 15 April 2021 |
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* |
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* Permission is hereby granted, free of charge, to any person obtaining a copy |
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* of this software and associated documentation files (the "Software"), to deal |
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* in the Software without restriction, including without limitation the rights |
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* to use, copy, modify, merge, publish, distribute, sublicense, and/or sell |
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* copies of the Software, and to permit persons to whom the Software is |
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* furnished to do so, subject to the following conditions: |
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* |
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* The above copyright notice and this permission notice shall be included in all |
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* copies or substantial portions of the Software. |
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* |
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* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR |
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* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, |
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* FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE |
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* AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER |
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* LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, |
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* OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE |
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* SOFTWARE. |
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*/ |
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#include "radioModulatedGenerator_F32.h" |
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// 513 values of the sine wave in a float array:
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#include "sinTable512_f32.h" |
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void radioModulatedGenerator_F32::update(void) { |
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audio_block_f32_t *inAmpl, *inPhaseFreq; |
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audio_block_f32_t *outBlockI, *outBlockQ; |
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uint16_t index, i; |
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float32_t a, b, deltaPhase, phaseC, amSig; |
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uint32_t tt=micros(); |
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// Input 0 is for amplitude modulation.
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if(doAM) { |
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inAmpl = AudioStream_F32::receiveReadOnly_f32(0); |
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if (!inAmpl) return; |
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} |
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// Input 1 is for phase or frequency modulation.
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if(doPM || doFM) { |
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inPhaseFreq = AudioStream_F32::receiveReadOnly_f32(1); |
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if (!inPhaseFreq) { |
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if(doAM) AudioStream_F32::release(inAmpl); |
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return; |
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} |
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} |
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outBlockI = AudioStream_F32::allocate_f32(); // Output blocks
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if (!outBlockI) { |
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if(doAM) AudioStream_F32::release(inAmpl); |
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if(doPM || doFM) AudioStream_F32::release(inPhaseFreq); |
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return; |
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} |
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if(bothIQ) { |
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outBlockQ = AudioStream_F32::allocate_f32(); |
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if (!outBlockQ) { |
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if(doAM) AudioStream_F32::release(inAmpl); |
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if(doPM || doFM) AudioStream_F32::release(inPhaseFreq); |
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AudioStream_F32::release(outBlockI); |
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return; |
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} |
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} |
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for (i=0; i < block_length; i++) { |
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if(doPM) // Phase in inPhaseFreq->data[i] is scaled for (0.0, 2*PI)
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phaseS += (phaseIncrement0 + K512ON2PI*inPhaseFreq->data[i]); |
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else if(doFM) |
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phaseS += kp*(freq + inPhaseFreq->data[i]); // kp=512.0/sample_rate_Hz
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else |
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phaseS += phaseIncrement0; // No PM or FM alteration to carrier phase
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while (phaseS > 512.0f) |
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phaseS -= 512.0f; |
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while (phaseS < 0.0f) |
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phaseS += 512.0f; |
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index = (uint16_t) phaseS; // Does adding 0.5 here cut errors? <<<<<<<<<<<<<<<<<<
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deltaPhase = phaseS -(float32_t) index; |
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/* Read two nearest values of input value from the sin table */ |
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a = sinTable512_f32[index]; |
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b = sinTable512_f32[index+1]; |
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if(doAM) { |
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amSig = 1.0f + inAmpl->data[i]; |
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if(amSig<0.0f) |
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amSig = 0.0f; // Common def of AM going back to vacuum tubes
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outBlockI->data[i] = amplitude_pk*amSig*(a + 0.001953125*(b-a)*deltaPhase); /* Linear interpolation process */ |
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} |
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else |
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outBlockI->data[i] = amplitude_pk*(a + 0.001953125*(b-a)*deltaPhase); |
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if(bothIQ) { |
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/* Shift forward phaseQ_I and get cos. First, the calculation of index of the table */ |
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phaseC = phaseS + phaseQ_I; |
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while (phaseC > 512.0f) |
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phaseC -= 512.0f; |
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while (phaseC < 0.0f) |
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phaseC += 512.0f; |
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index = (uint16_t) phaseC; |
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deltaPhase = phaseC -(float32_t) index; |
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/* Read two nearest values of input value from the sin table */ |
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a = sinTable512_f32[index]; |
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b = sinTable512_f32[index+1]; |
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if(doAM) // amSig from above
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outBlockQ->data[i] = amplitudeQ_I*amplitude_pk*amSig*(a + 0.001953125*(b-a)*deltaPhase); |
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else |
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outBlockQ->data[i] = amplitudeQ_I*amplitude_pk*(a + 0.001953125*(b-a)*deltaPhase); |
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} |
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} |
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if(doAM) AudioStream_F32::release(inAmpl); |
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if(doPM || doFM) AudioStream_F32::release(inPhaseFreq); |
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AudioStream_F32::transmit(outBlockI, 0); |
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AudioStream_F32::release (outBlockI); |
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if(bothIQ) { |
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AudioStream_F32::transmit(outBlockQ, 1); |
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AudioStream_F32::release (outBlockQ); |
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} |
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Serial.println(micros() - tt); |
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} |
@ -0,0 +1,175 @@ |
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/* radioModulatedGenerator_F32.h
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* |
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* RadioModulatedGenerator_F32 class |
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* |
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* Created: Bob Larkin 15 April 2021 |
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* |
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* For AM, the input is the 0 (left) channel. 100% AM modulation corresponds |
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* to this input -1.0 to 1.0. Overmodulation (more that 100%) results in peak |
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* increases beyond twice amplitude, but full abrupt clipping at the |
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* bottom zero point. Clipping on the top would be in an external block, |
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* if desired |
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* |
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* For PM or FM (only one at a time) the input goes to the 1 channel. For PM, |
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* the input level corresponds to radians of phase change, + or -. For FM, |
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* the input correspondss to Hz of deviation. |
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* |
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* For digital modulation, such as QAM, there can be both phase and amplitude |
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* modulation. This would be set by |
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* doModulation_AM_PM_FM(true, true, false, bool _bothIQ) |
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* |
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* If _bothIQ is false, the output is all at channel 0. This is a standard |
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* modulated waveform as would be transmitted by wires or radio. If _bothIQ |
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* is true, a pair of outputs on channels 0 and 1 correspond to I and Q |
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* components, as would be used with "phasing mixers" to convert the transmit |
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* frequency. |
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* |
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* Amplitude and phase corrections can be applied when there I-Q outputs. |
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* This can compensate for errors in the external hardware. See the functions: |
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* phaseQ_I(float32_t ph) |
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* amplitudeQ_I(float32_t _a) |
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* |
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* Time: T3.6 update() block of 128 is about 53 microseconds AM Single output |
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* T4.x update() block of 128 is about 20 microseconds AM Single output |
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* T4.x update() block of 128 is about 35 microseconds AM I + Q outputs |
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* For T4.x, FM is 1 or 2 microseconds faster than AM. |
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* |
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* Copyright (c) 2021 Bob Larkin |
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* |
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* Permission is hereby granted, free of charge, to any person obtaining a copy |
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* of this software and associated documentation files (the "Software"), to deal |
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* in the Software without restriction, including without limitation the rights |
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* to use, copy, modify, merge, publish, distribute, sublicense, and/or sell |
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* copies of the Software, and to permit persons to whom the Software is |
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* furnished to do so, subject to the following conditions: |
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* |
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* The above copyright notice and this permission notice shall be included in all |
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* copies or substantial portions of the Software. |
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* |
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* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR |
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* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, |
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* FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE |
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* AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER |
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* LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, |
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* OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE |
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* SOFTWARE. |
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*/ |
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#ifndef modulate_AM_PM_FM_f32_h_ |
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#define modulate_AM_PM_FM_f32_h_ |
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#include "AudioStream_F32.h" |
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#include "arm_math.h" |
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#ifndef M_PI |
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#define M_PI 3.14159265358979323846 |
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#endif |
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#ifndef M_PI_2 |
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#define M_PI_2 1.57079632679489661923 |
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#endif |
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#ifndef M_TWOPI |
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#define M_TWOPI (M_PI * 2.0) |
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#endif |
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#define MF2_PI 6.2831853f |
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#define K512ON2PI 81.487331f |
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class radioModulatedGenerator_F32 : public AudioStream_F32 { |
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//GUI: inputs:2, outputs:2 //this line used for automatic generation of GUI node
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//GUI: shortName:Modulator //this line used for automatic generation of GUI node
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public: |
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radioModulatedGenerator_F32(void) : AudioStream_F32(2, inputQueueArray_f32) { } //uses default AUDIO_SAMPLE_RATE from AudioStream.h
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radioModulatedGenerator_F32(const AudioSettings_F32 &settings) : AudioStream_F32(2, inputQueueArray_f32) { |
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setSampleRate_Hz(settings.sample_rate_Hz); |
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setBlockLength(settings.audio_block_samples); |
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} |
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void frequency(float32_t fr) { // Center Frequency in Hz
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freq = fr; |
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if (freq < 0.0f) freq = 0.0f; |
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else if (freq > sample_rate_Hz/2.0f) freq = sample_rate_Hz/2.0f; |
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phaseIncrement0 = 512.0f * freq / sample_rate_Hz; |
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} |
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/* Externally, phase comes in the range (0,2*M_PI) keeping with C math functions
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* Internally, the full circle is represented as (0.0, 512.0). This is |
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* convenient for finding the entry to the sine table. |
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*/ |
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void phase_r(float32_t ph) { |
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while (ph < 0.0f) ph += MF2_PI; |
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while (ph > MF2_PI) ph -= MF2_PI; |
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phaseS = 512.0f * ph / MF2_PI; |
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return; |
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} |
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// phaseQ_I is the number of radians that the cosine output leads the
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// sine output. The default is M_PI_2 = pi/2 = 1.57079633 radians,
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// corresponding to 90.00 degrees cosine leading sine.
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void phaseQ_I_r(float32_t ph) { |
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while (ph < 0.0f) ph += MF2_PI; |
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while (ph > MF2_PI) ph -= MF2_PI; |
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// Internally a full circle is 512.00 of phase
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phaseQ_I = 512.0f * ph / MF2_PI; |
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return; |
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} |
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// amplitudeQ_I an amplitude unbalance introduced to the Q channel to
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// compensate for errors in external hardware..
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void amplitudeQI(float32_t _a) { |
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amplitudeQ_I = _a; |
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return; |
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} |
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// The amplitude, a, is the peak, as in zero-to-peak. This produces outputs
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// ranging from -a to +a. Both outputs are the same amplitude.
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// This will be multiplied by the AM input from Input 0. This is "power control"
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void amplitude(float32_t _a) { |
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amplitude_pk = _a; |
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return; |
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} |
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void doModulation_AM_PM_FM(bool _doAM, bool _doPM, bool _doFM, bool _bothIQ) { |
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doAM = _doAM; |
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doPM = _doPM; |
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doFM = _doFM; |
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if(doPM & doFM) doFM=false; // One at a time
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bothIQ = _bothIQ; |
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} |
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// Do not use. For now, dynamic sample rate is not generally supported.
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void setSampleRate_Hz(float32_t fs_Hz) { |
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sample_rate_Hz = fs_Hz; |
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// Check freq range
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if (freq > sample_rate_Hz/2.0f) freq = sample_rate_Hz/2.0f; |
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// update phase increment for new frequency, and kp
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phaseIncrement0 = 512.0f * freq/fs_Hz; |
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kp = 512.0f/sample_rate_Hz; |
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} |
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// Do not use. Dynamic block length is un-supported.
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void setBlockLength(uint16_t bl) { |
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if(bl > 128) bl = 128; |
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block_length = bl; |
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} |
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virtual void update(void); |
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private: |
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audio_block_f32_t *inputQueueArray_f32[2]; |
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float32_t freq = 10000.0f; // Center frequecy, Hz
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float32_t phaseS = 0.0f; |
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float32_t phaseQ_I = 128.00; |
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float32_t amplitudeQ_I = 1.0f; |
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float32_t amplitude_pk = 1.0f; |
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float32_t sample_rate_Hz = AUDIO_SAMPLE_RATE; // Base, center freq
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float32_t kp = 512.0/sample_rate_Hz; |
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float32_t phaseIncrement0 = kp*freq;; |
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uint16_t block_length = 128; |
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bool doAM = false; |
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bool doPM = false; |
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bool doFM = false; |
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bool bothIQ = false; // Quadrature outputs for analog mixers
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}; |
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#endif |
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