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OpenAudio_ArduinoLibrary/examples/BFSK/BFSK.ino

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/*
* BFSK.ino Test the BFSK at 1200 baud with repeated data.
* The Serial Monitor should print:
OpenAudio_ArduinoLibrary - Test BFSK
Resulting audio samples per data bit = 40
0The quick brown fox jumped...
1The quick brown fox jumped...
2The quick brown fox jumped...
3The quick brown fox jumped...
4The quick brown fox jumped...
Data send and receive complete
*
* F32 library
* Bob Larkin 5 June 2022
* Public Domain
*/
#include "OpenAudio_ArduinoLibrary.h"
#include "AudioStream_F32.h"
#include <Audio.h>
float* pDat = NULL;
float32_t fa, fb, delf, dAve; // For sweep
struct uartData* pData;
float32_t inFIRCoef[200];
float32_t inFIRadb[100];
float32_t inFIRData[528];
float32_t inFIRrdb[500];
// LPF FIR for 1200 baud
static float32_t LPF_FIR_Sinc[40] = {
0.025f, 0.025f, 0.025f, 0.025f, 0.025f, 0.025f, 0.025f, 0.025f,
0.025f, 0.025f, 0.025f, 0.025f, 0.025f, 0.025f, 0.025f, 0.025f,
0.025f, 0.025f, 0.025f, 0.025f, 0.025f, 0.025f, 0.025f, 0.025f,
0.025f, 0.025f, 0.025f, 0.025f, 0.025f, 0.025f, 0.025f, 0.025f,
0.025f, 0.025f, 0.025f, 0.025f, 0.025f, 0.025f, 0.025f, 0.025f};
// The next needs to be 128 + the size of the FIR coefficient array
float32_t FIRbuffer[128+40];
// T3.x supported sample rates: 2000, 8000, 11025, 16000, 22050, 24000, 32000, 44100, 44117, 48000,
// 88200, 88235 (44117*2), 95680, 96000, 176400, 176470, 192000
// T4.x supports any sample rate the codec will handle.
const float sample_rate_Hz = 48000.0f ; // 24000, 44117, or other frequencies listed above (untested)
const int audio_block_samples = 128; // Others untested
AudioSettings_F32 audio_settings(sample_rate_Hz, audio_block_samples); // Not used
RadioBFSKModulator_F32 modulator1(audio_settings);
AudioSynthGaussian_F32 gwn1;
AudioMixer4_F32 mixer4_1;
AudioFilterFIRGeneral_F32 inputFIR;
RadioFMDiscriminator_F32 fmDet1(audio_settings);
UART_F32 uart1(audio_settings);
AudioAnalyzeRMS_F32 rms1;
AudioOutputI2S_F32 audioOutI2S1(audio_settings);
AudioConnection_F32 patchCord1(modulator1, 0, mixer4_1, 0);
AudioConnection_F32 patchCord2(gwn1, 0, mixer4_1, 1);
AudioConnection_F32 patchCord4(mixer4_1, 0, inputFIR, 0);
AudioConnection_F32 patchCord5(inputFIR, 0, rms1, 0);
AudioConnection_F32 patchCord7(inputFIR, 0, fmDet1, 0);
AudioConnection_F32 patchcord8(fmDet1, 0, uart1, 0);
AudioControlSGTL5000 sgtl5000_1;
void setup() {
uint32_t spdb;
static float32_t snrDB = 15.0f;
static uint16_t dm0;
static uint32_t nn, ii;
static char ch[32];
static uint32_t t = 0UL;
Serial.begin(300); // Any value, it is not used
delay(1000);
Serial.println("OpenAudio_ArduinoLibrary - Test BFSK");
AudioMemory_F32(30, audio_settings);
// Enable the audio shield, select input, and enable output
sgtl5000_1.enable(); //start the audio board
spdb = modulator1.setBFSK(1200.0f, 10, 1200.0f, 2200.0f);
modulator1.setLPF(NULL, NULL, 0); // No LPF
modulator1.amplitude(1.00f);
Serial.print("Resulting audio samples per data bit = ");
Serial.println(spdb);
mixer4_1.gain(0, 1.0f); // Modulator in
mixer4_1.gain(1, 1.0f); // Gaussian noise in
// Design a bandpass filter to limit the input to the FM discriminator
for(int jj=0; jj<12; jj++) inFIRadb[jj] = -100.0f;
for(int jj=3; jj<=11; jj++) inFIRadb[jj] = 0.0f;
for(int jj=12; jj<100; jj++) inFIRadb[jj] = -100.0f;
inputFIR.FIRGeneralNew(inFIRadb, 200, inFIRCoef, 40.0f, inFIRData);
fmDet1.filterOutFIR(LPF_FIR_Sinc, 40, FIRbuffer, 0.99f); // Precede initialize
fmDet1.initializeFMDiscriminator(1100.0f, 2350.0f, 2.0f, 3.0f);
uart1.setUART(40, 20, 8, PARITY_NONE, 1);
// See BFSK_random.ino for details of S/N measurement
// Signal power = 470.831299, 5625
// Noise power = 471.335632, 5625
// S/N in dB for S set to 0.414476 and N set to 1.0f: -0.0046
// S/N=7 dB marginal but S/N=14 dB is solid
snrDB = 14.0f;
modulator1.amplitude(pow(10.0, 0.05f*(snrDB-7.65f)));
gwn1.amplitude(1.0f);
// Send a little data, five of these:
// index ii 0 10 20 30
// v v v v
strcpy(ch, "0The quick brown fox jumped...\n"); // 32 char including ending 0
ii = 0; nn = 0;
modulator1.bufferClear();
delay(40);
// Get UART synced up
if( modulator1.bufferHasSpace() )
modulator1.sendData(0X200); // 0X00
if( modulator1.bufferHasSpace() )
modulator1.sendData(0X200);
while(nn < 5)
{
if( modulator1.bufferHasSpace() )
{
// Serial.print("Send"); Serial.println((char)ch[ii]);
dm0 = (uint16_t)ch[ii++];
if(ii>30) // Sends all including \n, but not the string zero.
{
ii=0;
nn++;
ch[0]++; // Left hand character, 0 to 4
}
modulator1.sendData(0X200 | (dm0 << 1)); // Format ASCII to 8N1 serial
}
if(uart1.getNDataBuffer() > 0L)
{
pData = uart1.readUartData();
Serial.print((char)pData->data);
}
}
// Receive takes longer than transmit, so wait for the rest.
t = millis();
while((millis() - t) < 2000UL) // Wait few seconds...
{
if(uart1.getNDataBuffer() > 0L)
{
pData = uart1.readUartData();
Serial.print((char)pData->data);
}
}
Serial.println("Data send and receive complete");
}
void loop() {
}