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125 lines
4.6 KiB
125 lines
4.6 KiB
/*
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* TestConvolutionalFilter.ino Bob Larkin 2 Feb 2022
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* Measure frequency response of convolution filtering.
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*
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* This uses the Goertzel algoritm of AudioAnalyzeToneDetect_F32 as
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* a "direct conversion receiver." This provides the excellent
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* selectivity needed for measuring below -100 dBfs.
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*
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* Comparison with 512 tap FIR filtering is included, but double slash
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* commented out.
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*
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* Public Domain - Teensy
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* Revised to only allow T3.5, T3.6 or T4.x Bob L 19 Jan 2023
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*/
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#if defined(__MK64FX512__) || defined(__MK66FX1M0__) || defined(__IMXRT1062__)
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#include "Audio.h"
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#include "OpenAudio_ArduinoLibrary.h"
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#include "AudioStream_F32.h"
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#include "AudioFilterConvolution_F32.h"
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AudioSynthSineCosine_F32 sine_cos1; //xy=87,151
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AudioFilterConvolution_F32 convFilt1; //xy=163,245
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//AudioFilterFIRGeneral_F32 filterFIRgeneral1; //xy=285,177
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AudioOutputI2S_F32 audioOutI2S1; //xy=357,337
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//AudioAnalyzeToneDetect_F32 toneDet1; //xy=377,259
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AudioAnalyzeToneDetect_F32 toneDet2; //xy=378,299
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//AudioConnection_F32 patchCord1(sine_cos1, 0, filterFIRgeneral1, 0);
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AudioConnection_F32 patchCord2(sine_cos1, 1, convFilt1, 0);
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AudioConnection_F32 patchCord3(convFilt1, toneDet2);
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AudioConnection_F32 patchCord4(convFilt1, 0, audioOutI2S1, 0);
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//AudioConnection_F32 patchCord5(filterFIRgeneral1, 0, toneDet1, 0);
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AudioControlSGTL5000 sgtl5000_1; //xy=164,343
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// CAUTION that audio output is intended for an oscilloscope and may be very
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// VERY loud in a speaker or headphone.
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//float32_t coeffFIR[512];
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//float32_t stateFIR[1160];
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//float32_t attenFIR[256];
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void setup(void) {
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AudioMemory(5);
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AudioMemory_F32(50);
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Serial.begin(300); delay(1000);
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Serial.println("*** Test Convolutional Filtering routine for F32 ***");
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sine_cos1.frequency(1000.0f);
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sine_cos1.amplitude(1.0f);
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// toneDet1.frequency(100.0f, 5);
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toneDet2.frequency(100.0f, 5);
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// *** Un-comment just ONE of the following filters ***
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// Low Pass Filter, 4000 Hz cut off, 60 dB first sidelobe
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//convFilt1.initFilter(4000.0f, 60.0f, LOWPASS, 0.0f);
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// High Pass Filter, 2000 Hz cut off, 25 dB first sidelobe
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//convFilt1.initFilter(2000.0f, 25.0f, HIGHPASS, 0.0f);
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// IK8YFW CW - Centered at 800Hz, 40 db SL, 2=BPF, width = 1200Hz
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//convFilt1.initFilter(800.0f, 40.0f, BANDPASS, 1200.0f);
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// IK8YFW SSB - Centered at 1500Hz, 60 db SL, 2=BPF, width = 3000Hz
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convFilt1.initFilter(1500.0f, 60.0f, BANDPASS, 3000.0f);
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// Band Reject filter, Centered at 6000Hz, 50 db SL, 3=BRF, width = 2000Hz
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//convFilt1.initFilter(6000.0f, 60.0f, BANDREJECT, 2000.0f);
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// BP filter, Centered at 6000Hz, 50 db SL, 2=BPF, width = 2000Hz
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//convFilt1.initFilter(6000.0f, 60.0f, BANDPASS, 2000.0f);
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// INO designed FIR coefficients
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// Simple 7 tap LPF 4 kHz with 20 dB stop band
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/*
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float32_t taps[7] = {
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0.06597017637343348f,
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0.18600068295067165f,
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0.21675619343104624f,
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0.2802036313373938f,
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0.21675619343104624f,
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0.18600068295067165f,
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0.06597017637343348f};
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//// Get the pointer to the coefficient storage
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float32_t* cf=convFilt1.getCoeffPtr();
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// Load the filter and pad coefficients with zeros
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for(int ii=0; ii<7; ii++) cf[ii] = taps[ii];
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for(int ii=7; ii<512; ii++) cf[ii] = 0.0f;
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convFilt1.initFilter(); // Generate the filter mask
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*/
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// Alternatively, the passthrough case:
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//convFilt1.passThrough(1);
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// Design for direct FIR. This sets frequency response.
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// Bin for 4kHz at 44.117kHz sample rate and 400 coeff's is (4000/44117) * (512/2) = 23.2
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// for(int ii=0; ii<47; ii++) attenFIR[ii] = 0.0f;
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// for(int ii=47; ii<256; ii++) attenFIR[ii] = -150.0f;
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// FIRGeneralNew(float *adb, uint16_t nFIR, float *cf32f, float kdb, float *pStateArray);
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// filterFIRgeneral1.FIRGeneralNew(attenFIR, 512, coeffFIR, 60.0, stateFIR);
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// DSP measure frequency response in dB uniformly spaced from 100 to 20000 Hz
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Serial.println("Freq Hz Conv dB FIR dB");
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for(float32_t f=100.0; f<=20000.0f; f+=50.0f)
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{
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sine_cos1.frequency(f);
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// toneDet1.frequency(f, (f>2000.0f ? 100 : 5));
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toneDet2.frequency(f, (f>2000.0f ? 100 : 5));
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delay(50);
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// while(!toneDet1.available())delay(2) ;
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// toneDet1.read();
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while(!toneDet2.available())delay(2) ;
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toneDet2.read();
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while(!toneDet2.available())delay(2) ;
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Serial.print(f);
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Serial.print(", ");
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while(!toneDet2.available())delay(2) ;
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Serial.println(20.0f*log10f(toneDet2.read()), 3);
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}
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}
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void loop() {
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}
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// End T3.5, T3.6 or T4.x
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#endif
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