Tuesday, 20 March 2018

Homebrew SSB SDR Rig

Part 1. Quadrature Oscillator. See my ZL2CTM YouTube channel for accompanying video.



Code. This will be updated as additional SDR DSP functions are added.

#include <Wire.h>                          // I2C comms
#include <si5351.h>                        // Si5351 library
#include <LiquidCrystal_I2C.h>             // LCD library


// Define Constants and Vaviables
static const long bandStart = 1000000;     // start of HF band
static const long bandEnd =   30000000;    // end of HF band
static const long bandInit =  3690000;     // where to initially set the frequency
volatile long oldfreq = 0;
volatile long freq = bandInit ;
volatile long radix = 1000;                // how much to change the frequency by, clicking the rotary encoder will change this.
volatile int updatedisplay = 0;

// Rotary Encoder
static const int pushPin = 39;
static const int rotBPin = 36;
static const int rotAPin = 35;
volatile int rotState = 0;
volatile int rotAval = 1;
volatile int rotBval = 1;
volatile int rotAcc = 0;

// Instantiate the Objects
LiquidCrystal_I2C lcd(0x3F, 16, 2);       // set the LCD address to either 0x27 or 0x3F for a 16 chars and 2 line display
Si5351 si5351;


void setup()
{
  // Set up input switches
  pinMode(rotAPin, INPUT);
  pinMode(rotBPin, INPUT);
  pinMode(pushPin, INPUT);
  digitalWrite(rotAPin, HIGH);
  digitalWrite(rotBPin, HIGH);
  digitalWrite(pushPin, HIGH);

  // Set up interrupt pins
  attachInterrupt(digitalPinToInterrupt(rotAPin), ISRrotAChange, CHANGE);
  attachInterrupt(digitalPinToInterrupt(rotBPin), ISRrotBChange, CHANGE);

  // Initialise the lcd
  lcd.begin();
  lcd.backlight();

  // Initialise the DDS
  si5351.init(SI5351_CRYSTAL_LOAD_8PF, 0);
  si5351.set_pll(SI5351_PLL_FIXED, SI5351_PLLA);
  si5351.drive_strength(SI5351_CLK0, SI5351_DRIVE_8MA);
  si5351.set_freq((freq * 100ULL), SI5351_PLL_FIXED, SI5351_CLK0);

  UpdateDisplay();
}


void loop()
{
  if (freq != oldfreq)
  {
    UpdateDisplay();
    SendFrequency();
    oldfreq = freq;
  }

  if (digitalRead(pushPin) == LOW)
  {
    delay(10);
    while (digitalRead(pushPin) == LOW)
    {
      if (updatedisplay == 1)
      {
        UpdateDisplay();
        updatedisplay = 0;
      }
    }
    delay(50);
  }
}


// Interrupt routines
void ISRrotAChange()
{
  if (digitalRead(rotAPin))
  {
    rotAval = 1;
    UpdateRot();
  }
  else
  {
    rotAval = 0;
    UpdateRot();
  }
}


void ISRrotBChange()
{
  if (digitalRead(rotBPin))
  {
    rotBval = 1;
    UpdateRot();
  }
  else
  {
    rotBval = 0;
    UpdateRot();
  }
}


void UpdateRot()
{
  switch (rotState)
  {

    case 0:                                         // Idle state, look for direction
      if (!rotBval)
        rotState = 1;                               // CW 1
      if (!rotAval)
        rotState = 11;                              // CCW 1
      break;

    case 1:                                         // CW, wait for A low while B is low
      if (!rotBval)
      {
        if (!rotAval)
        {
          // either increment radixindex or freq
          if (digitalRead(pushPin) == LOW)
          {
            updatedisplay = 1;
            if (radix == 1000000)
              radix = 100000;
            else if (radix == 100000)
              radix = 10000;
            else if (radix == 10000)
              radix = 1000;
            else if (radix == 1000)
              radix = 100;
            else if (radix == 100)
              radix = 10;
            else if (radix == 10)
              radix = 1;
            else
              radix = 1000000;
          }
          else
          {
            freq = (freq + radix);
            if (freq > bandEnd)
              freq = bandEnd;
          }
          rotState = 2;                             // CW 2
        }
      }
      else if (rotAval)
        rotState = 0;                               // It was just a glitch on B, go back to start
      break;

    case 2:                                         // CW, wait for B high
      if (rotBval)
        rotState = 3;                               // CW 3
      break;

    case 3:                                         // CW, wait for A high
      if (rotAval)
        rotState = 0;                               // back to idle (detent) state
      break;

    case 11:                                        // CCW, wait for B low while A is low
      if (!rotAval)
      {
        if (!rotBval)
        {
          // either decrement radixindex or freq
          if (digitalRead(pushPin) == LOW)
          {
            updatedisplay = 1;
            if (radix == 1)
              radix = 10;
            else if (radix == 10)
              radix = 100;
            else if (radix == 100)
              radix = 1000;
            else if (radix == 1000)
              radix = 10000;
            else if (radix == 10000)
              radix = 100000;
            else if (radix == 100000)
              radix = 1000000;
            else
              radix = 1;
          }
          else
          {
            freq = (freq - radix);
            if (freq < bandStart)
              freq = bandStart;
          }
          rotState = 12;                            // CCW 2
        }
      }
      else if (rotBval)
        rotState = 0;                               // It was just a glitch on A, go back to start
      break;

    case 12:                                        // CCW, wait for A high
      if (rotAval)
        rotState = 13;                              // CCW 3
      break;

    case 13:                                        // CCW, wait for B high
      if (rotBval)
        rotState = 0;                               // back to idle (detent) state
      break;
  }
}


void UpdateDisplay()
{
  lcd.cursor();                                     // Turn on the cursor
  lcd.setCursor(0, 0);
  lcd.print("        ");
  lcd.setCursor(0, 0);
  lcd.print(freq);
  lcd.setCursor(10, 0);
  lcd.print("ZL2CTM");

  lcd.setCursor(0, 1);
  lcd.print("        ");
  lcd.setCursor(0, 1);

  if (freq > 9999999)
  {
    if (radix == 1)
      lcd.setCursor(7, 0);
    if (radix == 10)
      lcd.setCursor(6, 0);
    if (radix == 100)
      lcd.setCursor(5, 0);
    if (radix == 1000)
      lcd.setCursor(4, 0);
    if (radix == 10000)
      lcd.setCursor(3, 0);
    if (radix == 100000)
      lcd.setCursor(2, 0);
    if (radix == 1000000)
      lcd.setCursor(1, 0);

  }
  if (freq <= 9999999)
  {
    if (radix == 1)
      lcd.setCursor(6, 0);
    if (radix == 10)
      lcd.setCursor(5, 0);
    if (radix == 100)
      lcd.setCursor(4, 0);
    if (radix == 1000)
      lcd.setCursor(3, 0);
    if (radix == 10000)
      lcd.setCursor(2, 0);
    if (radix == 100000)
      lcd.setCursor(1, 0);
    if (radix == 1000000)
      lcd.setCursor(0, 0);
  }
}



void SendFrequency()
{
  si5351.set_freq((freq * 4) * 100ULL, SI5351_PLL_FIXED, SI5351_CLK0);
}


*****************************************************************************

Dual Quadrature NE612 Direct Conversion Front End



Antenna RF Amplifier

 Please note the collector inductor below is 1mH NOT 1uH




80m/20m Bandpass Filter



Audio Pass-through Test Code

#include <Wire.h>                          // I2C comms
#include <si5351.h>                        // Si5351 library
#include <LiquidCrystal_I2C.h>             // LCD library
#include <Audio.h>                         // Teensy audio library

// Define Constants and Vaviables
static const long bandStart = 1000000;     // start of HF band
static const long bandEnd =   30000000;    // end of HF band
static const long bandInit =  3690000;     // where to initially set the frequency
volatile long oldfreq = 0;
volatile long freq = bandInit ;
volatile long radix = 1000;                // how much to change the frequency by, clicking the rotary encoder will change this.
volatile int updatedisplay = 0;

// Rotary Encoder
static const int pushPin = 39;
static const int rotBPin = 36;
static const int rotAPin = 35;
volatile int rotState = 0;
volatile int rotAval = 1;
volatile int rotBval = 1;
volatile int rotAcc = 0;

// Instantiate the Objects
LiquidCrystal_I2C lcd(0x3F, 16, 2);       // Set the LCD address to either 0x27 or 0x3F for a 16 chars and 2 line display
Si5351 si5351;                            // The Si5351 DDS
AudioControlSGTL5000    audioShield;      // The Teensy audio CODEC on the audio shield


// Audio shield
AudioInputI2S           audioInput;                                   // What we call the input to the audio shield
AudioOutputI2S          audioOutput;                                  // What we call the output of the audio shield
AudioConnection         patchCord5(audioInput, 0, audioOutput, 0);    // Left channel in to left channel out
AudioConnection         patchCord10(audioInput, 1, audioOutput, 1);   // Right channel in to right channel out

void setup()
{
  // Setup input switches
  pinMode(rotAPin, INPUT);
  pinMode(rotBPin, INPUT);
  pinMode(pushPin, INPUT);
  digitalWrite(rotAPin, HIGH);
  digitalWrite(rotBPin, HIGH);
  digitalWrite(pushPin, HIGH);

  // Setup interrupt pins
  attachInterrupt(digitalPinToInterrupt(rotAPin), ISRrotAChange, CHANGE);
  attachInterrupt(digitalPinToInterrupt(rotBPin), ISRrotBChange, CHANGE);

  // Setup the lcd
  lcd.begin();
  lcd.backlight();

  // Setup the DDS
  si5351.init(SI5351_CRYSTAL_LOAD_8PF, 0);
  si5351.set_pll(SI5351_PLL_FIXED, SI5351_PLLA);
  si5351.drive_strength(SI5351_CLK0, SI5351_DRIVE_8MA);
  si5351.set_freq((freq * 100ULL), SI5351_PLL_FIXED, SI5351_CLK0);

  // Setup the audio shield
  AudioNoInterrupts();
  AudioMemory(16);
  audioShield.enable();
  audioShield.inputSelect(AUDIO_INPUT_LINEIN);
  audioShield.volume(0.7);
  audioShield.unmuteLineout();
  AudioInterrupts();

  UpdateDisplay();
}


void loop()
{
  if (freq != oldfreq)
  {
    UpdateDisplay();
    SendFrequency();
    oldfreq = freq;
  }

  if (digitalRead(pushPin) == LOW)
  {
    delay(10);
    while (digitalRead(pushPin) == LOW)
    {
      if (updatedisplay == 1)
      {
        UpdateDisplay();
        updatedisplay = 0;
      }
    }
    delay(50);
  }
}


// Interrupt routines
void ISRrotAChange()
{
  if (digitalRead(rotAPin))
  {
    rotAval = 1;
    UpdateRot();
  }
  else
  {
    rotAval = 0;
    UpdateRot();
  }
}


void ISRrotBChange()
{
  if (digitalRead(rotBPin))
  {
    rotBval = 1;
    UpdateRot();
  }
  else
  {
    rotBval = 0;
    UpdateRot();
  }
}


void UpdateRot()
{
  switch (rotState)
  {

    case 0:                                         // Idle state, look for direction
      if (!rotBval)
        rotState = 1;                               // CW 1
      if (!rotAval)
        rotState = 11;                              // CCW 1
      break;

    case 1:                                         // CW, wait for A low while B is low
      if (!rotBval)
      {
        if (!rotAval)
        {
          // either increment radixindex or freq
          if (digitalRead(pushPin) == LOW)
          {
            updatedisplay = 1;
            if (radix == 1000000)
              radix = 100000;
            else if (radix == 100000)
              radix = 10000;
            else if (radix == 10000)
              radix = 1000;
            else if (radix == 1000)
              radix = 100;
            else if (radix == 100)
              radix = 10;
            else if (radix == 10)
              radix = 1;
            else
              radix = 1000000;
          }
          else
          {
            freq = (freq + radix);
            if (freq > bandEnd)
              freq = bandEnd;
          }
          rotState = 2;                             // CW 2
        }
      }
      else if (rotAval)
        rotState = 0;                               // It was just a glitch on B, go back to start
      break;

    case 2:                                         // CW, wait for B high
      if (rotBval)
        rotState = 3;                               // CW 3
      break;

    case 3:                                         // CW, wait for A high
      if (rotAval)
        rotState = 0;                               // back to idle (detent) state
      break;

    case 11:                                        // CCW, wait for B low while A is low
      if (!rotAval)
      {
        if (!rotBval)
        {
          // either decrement radixindex or freq
          if (digitalRead(pushPin) == LOW)
          {
            updatedisplay = 1;
            if (radix == 1)
              radix = 10;
            else if (radix == 10)
              radix = 100;
            else if (radix == 100)
              radix = 1000;
            else if (radix == 1000)
              radix = 10000;
            else if (radix == 10000)
              radix = 100000;
            else if (radix == 100000)
              radix = 1000000;
            else
              radix = 1;
          }
          else
          {
            freq = (freq - radix);
            if (freq < bandStart)
              freq = bandStart;
          }
          rotState = 12;                            // CCW 2
        }
      }
      else if (rotBval)
        rotState = 0;                               // It was just a glitch on A, go back to start
      break;

    case 12:                                        // CCW, wait for A high
      if (rotAval)
        rotState = 13;                              // CCW 3
      break;

    case 13:                                        // CCW, wait for B high
      if (rotBval)
        rotState = 0;                               // back to idle (detent) state
      break;
  }
}


void UpdateDisplay()
{
  lcd.cursor();                                     // Turn on the cursor
  lcd.setCursor(0, 0);
  lcd.print("        ");
  lcd.setCursor(0, 0);
  lcd.print(freq);
  lcd.setCursor(10, 0);
  lcd.print("ZL2CTM");

  lcd.setCursor(0, 1);
  lcd.print("        ");
  lcd.setCursor(0, 1);

  if (freq > 9999999)
  {
    if (radix == 1)
      lcd.setCursor(7, 0);
    if (radix == 10)
      lcd.setCursor(6, 0);
    if (radix == 100)
      lcd.setCursor(5, 0);
    if (radix == 1000)
      lcd.setCursor(4, 0);
    if (radix == 10000)
      lcd.setCursor(3, 0);
    if (radix == 100000)
      lcd.setCursor(2, 0);
    if (radix == 1000000)
      lcd.setCursor(1, 0);

  }
  if (freq <= 9999999)
  {
    if (radix == 1)
      lcd.setCursor(6, 0);
    if (radix == 10)
      lcd.setCursor(5, 0);
    if (radix == 100)
      lcd.setCursor(4, 0);
    if (radix == 1000)
      lcd.setCursor(3, 0);
    if (radix == 10000)
      lcd.setCursor(2, 0);
    if (radix == 100000)
      lcd.setCursor(1, 0);
    if (radix == 1000000)
      lcd.setCursor(0, 0);
  }
}



void SendFrequency()
{
  si5351.set_freq((freq * 4) * 100ULL, SI5351_PLL_FIXED, SI5351_CLK0);
}

************************************************************************

AF Amplifier

 Note. In the schematic below the audio output is from Pin 5 on the NE612, NOT 6 or 9. 




Receive Test Code

 // Libraries
#include <Wire.h>                          // I2C comms library
#include <si5351.h>                        // Si5351Jason library
#include <LiquidCrystal_I2C.h>             // LCD library
#include <Audio.h>                         // Teensy audio library

// Number of Filter Coefficients
#define NO_HILBERT_COEFFS 70               // Used to define the Hilbert transform filter arrays. More typical than 'const int'.

// Define Constants and Vaviables
static const long bandStart = 1000000;     // start of HF band
static const long bandEnd =   30000000;    // end of HF band
static const long bandInit =  3690000;     // where to initially set the frequency
volatile long oldfreq = 0;
volatile long freq = bandInit ;
volatile long radix = 1000;                // how much to change the frequency by clicking the rotary encoder will change this.
volatile int updatedisplay = 0;

// Rotary Encoder
static const int pushPin = 39;
static const int rotBPin = 36;
static const int rotAPin = 35;
volatile int rotState = 0;
volatile int rotAval = 1;
volatile int rotBval = 1;
volatile int rotAcc = 0;


// Iowa Hills Hilbert transform filter coefficients
const short Hilbert_Plus_45_Coeffs[NO_HILBERT_COEFFS] = {
  (short)(32768 * -0.000287988910943357),
  (short)(32768 * -0.000383511439791303),
  (short)(32768 * -0.000468041804899774),
  (short)(32768 * -0.000529324432676899),
  (short)(32768 * -0.000569479602046985),
  (short)(32768 * -0.000616670267768531),
  (short)(32768 * -0.000731530748681977),
  (short)(32768 * -0.001002372095321225),
  (short)(32768 * -0.001525299390682192),
  (short)(32768 * -0.002370114347025230),
  (short)(32768 * -0.003539247773172147),
  (short)(32768 * -0.004932965382552984),
  (short)(32768 * -0.006337182914262393),
  (short)(32768 * -0.007448193692118567),
  (short)(32768 * -0.007940501940620482),
  (short)(32768 * -0.007570802072162988),
  (short)(32768 * -0.006296120449841751),
  (short)(32768 * -0.004371955618154949),
  (short)(32768 * -0.002391875073164555),
  (short)(32768 * -0.001236984700413469),
  (short)(32768 * -0.001922560128827416),
  (short)(32768 * -0.005356720327533458),
  (short)(32768 * -0.012055656297010635),
  (short)(32768 * -0.021882952959947619),
  (short)(32768 * -0.033888748300090733),
  (short)(32768 * -0.046312736456333638),
  (short)(32768 * -0.056783367797647665),
  (short)(32768 * -0.062699937453677912),
  (short)(32768 * -0.061735375084135742),
  (short)(32768 * -0.052358513976237808),
  (short)(32768 * -0.034257179158167443),
  (short)(32768 * -0.008554500746482946),
  (short)(32768 * 0.022249911747384360),
  (short)(32768 * 0.054622962942346594),
  (short)(32768 * 0.084568844473140448),
  (short)(32768 * 0.108316122839950818),
  (short)(32768 * 0.122979341462627859),
  (short)(32768 * 0.127056096658453188),
  (short)(32768 * 0.120656295327679283),
  (short)(32768 * 0.105420364259485699),
  (short)(32768 * 0.084152608145489444),
  (short)(32768 * 0.060257510644444748),
  (short)(32768 * 0.037105711921879434),
  (short)(32768 * 0.017464092086704748),
  (short)(32768 * 0.003100559033325746),
  (short)(32768 * -0.005373489802481697),
  (short)(32768 * -0.008418211280310166),
  (short)(32768 * -0.007286730644726664),
  (short)(32768 * -0.003638388931163832),
  (short)(32768 * 0.000858330713630433),
  (short)(32768 * 0.004847436504682235),
  (short)(32768 * 0.007476399317750315),
  (short)(32768 * 0.008440227567663121),
  (short)(32768 * 0.007898970420636600),
  (short)(32768 * 0.006314366257036837),
  (short)(32768 * 0.004261033495040515),
  (short)(32768 * 0.002261843500794377),
  (short)(32768 * 0.000680212977485724),
  (short)(32768 * -0.000319493110301691),
  (short)(32768 * -0.000751893569425181),
  (short)(32768 * -0.000752248417868501),
  (short)(32768 * -0.000505487955986662),
  (short)(32768 * -0.000184645628631330),
  (short)(32768 * 0.000087913008490067),
  (short)(32768 * 0.000253106348867209),
  (short)(32768 * 0.000306473486382603),
  (short)(32768 * 0.000277637042003169),
  (short)(32768 * 0.000207782317481292),
  (short)(32768 * 0.000132446796990356),
  (short)(32768 * 0.000072894261560354)
};

// Iowa Hills Hilbert transform filter coefficients
const short Hilbert_Minus_45_Coeffs[NO_HILBERT_COEFFS] = {
  (short)(32768 * -0.000072894261560345),
  (short)(32768 * -0.000132446796990344),
  (short)(32768 * -0.000207782317481281),
  (short)(32768 * -0.000277637042003168),
  (short)(32768 * -0.000306473486382623),
  (short)(32768 * -0.000253106348867259),
  (short)(32768 * -0.000087913008490148),
  (short)(32768 * 0.000184645628631233),
  (short)(32768 * 0.000505487955986583),
  (short)(32768 * 0.000752248417868491),
  (short)(32768 * 0.000751893569425298),
  (short)(32768 * 0.000319493110301983),
  (short)(32768 * -0.000680212977485245),
  (short)(32768 * -0.002261843500793748),
  (short)(32768 * -0.004261033495039842),
  (short)(32768 * -0.006314366257036280),
  (short)(32768 * -0.007898970420636345),
  (short)(32768 * -0.008440227567663343),
  (short)(32768 * -0.007476399317751102),
  (short)(32768 * -0.004847436504683540),
  (short)(32768 * -0.000858330713632029),
  (short)(32768 * 0.003638388931162351),
  (short)(32768 * 0.007286730644725833),
  (short)(32768 * 0.008418211280310565),
  (short)(32768 * 0.005373489802483816),
  (short)(32768 * -0.003100559033321630),
  (short)(32768 * -0.017464092086698697),
  (short)(32768 * -0.037105711921871905),
  (short)(32768 * -0.060257510644436532),
  (short)(32768 * -0.084152608145481672),
  (short)(32768 * -0.105420364259479538),
  (short)(32768 * -0.120656295327675800),
  (short)(32768 * -0.127056096658453216),
  (short)(32768 * -0.122979341462631633),
  (short)(32768 * -0.108316122839958146),
  (short)(32768 * -0.084568844473150454),
  (short)(32768 * -0.054622962942358168),
  (short)(32768 * -0.022249911747396132),
  (short)(32768 * 0.008554500746472333),
  (short)(32768 * 0.034257179158159054),
  (short)(32768 * 0.052358513976232306),
  (short)(32768 * 0.061735375084133286),
  (short)(32768 * 0.062699937453678217),
  (short)(32768 * 0.056783367797650072),
  (short)(32768 * 0.046312736456337288),
  (short)(32768 * 0.033888748300094730),
  (short)(32768 * 0.021882952959951244),
  (short)(32768 * 0.012055656297013388),
  (short)(32768 * 0.005356720327535105),
  (short)(32768 * 0.001922560128828006),
  (short)(32768 * 0.001236984700413229),
  (short)(32768 * 0.002391875073163812),
  (short)(32768 * 0.004371955618154038),
  (short)(32768 * 0.006296120449840938),
  (short)(32768 * 0.007570802072162439),
  (short)(32768 * 0.007940501940620253),
  (short)(32768 * 0.007448193692118624),
  (short)(32768 * 0.006337182914262643),
  (short)(32768 * 0.004932965382553323),
  (short)(32768 * 0.003539247773172483),
  (short)(32768 * 0.002370114347025498),
  (short)(32768 * 0.001525299390682370),
  (short)(32768 * 0.001002372095321316),
  (short)(32768 * 0.000731530748682004),
  (short)(32768 * 0.000616670267768521),
  (short)(32768 * 0.000569479602046963),
  (short)(32768 * 0.000529324432676881),
  (short)(32768 * 0.000468041804899765),
  (short)(32768 * 0.000383511439791304),
  (short)(32768 * 0.000287988910943362)
};


// Instantiate the Objects
LiquidCrystal_I2C lcd(0x3F, 16, 2);       // Name for the LCD. Set the LCD address to either 0x27 or 0x3F for a 16 chars and 2 line display
Si5351 si5351;                            // Name for the Si5351 DDS
AudioControlSGTL5000    audioShield;      // Name for the Teensy audio CODEC on the audio shield

// Audio shield
AudioInputI2S           audioInput;                                           // Name for the input to the audio shield
AudioOutputI2S          audioOutput;                                          // Name for the output of the audio shield
// Receiver
AudioFilterFIR          RX_Hilbert_Plus_45;                                   // Name for the RX +45 Hilbert transform
AudioFilterFIR          RX_Hilbert_Minus_45;                                  // Name for the RX +45 Hilbert transform
AudioMixer4             RX_Summer;                                            // Name for the RX summer

// Audio connections
AudioConnection         patchCord5(audioInput, 0, RX_Hilbert_Plus_45, 0);     // Left channel in Hilbert transform +45
AudioConnection         patchCord10(audioInput, 1, RX_Hilbert_Minus_45, 0);   // Right channel in Hilbert transform -45
AudioConnection         patchCord15(RX_Hilbert_Plus_45, 0, RX_Summer, 0);     // Hilbert transform +45 to receiver summer
AudioConnection         patchCord20(RX_Hilbert_Minus_45, 0, RX_Summer, 1);    // Hilbert transform -45 to receiver summer
AudioConnection         patchCord25(RX_Summer, 0, audioOutput, 0);            // Receiver summer to receiver LPF


void setup()
{
  // Setup input switches
  pinMode(rotAPin, INPUT);
  pinMode(rotBPin, INPUT);
  pinMode(pushPin, INPUT);
  digitalWrite(rotAPin, HIGH);
  digitalWrite(rotBPin, HIGH);
  digitalWrite(pushPin, HIGH);

  // Setup interrupt pins
  attachInterrupt(digitalPinToInterrupt(rotAPin), ISRrotAChange, CHANGE);
  attachInterrupt(digitalPinToInterrupt(rotBPin), ISRrotBChange, CHANGE);

  // Setup the lcd
  lcd.begin();
  lcd.backlight();

  // Setup the DDS
  si5351.init(SI5351_CRYSTAL_LOAD_8PF, 0);
  si5351.set_pll(SI5351_PLL_FIXED, SI5351_PLLA);
  si5351.drive_strength(SI5351_CLK0, SI5351_DRIVE_8MA);
  si5351.set_freq((freq * 100ULL), SI5351_PLL_FIXED, SI5351_CLK0);

  // Setup the audio shield
  AudioNoInterrupts();
  AudioMemory(16);
  audioShield.enable();
  audioShield.volume(0.7);            // Constant. Use external volume control on the audio amp
  AudioInterrupts();

  // Setup transceiver mode
  Turn_On_Receiver();
  UpdateDisplay();
}

void loop()
{
  if (freq != oldfreq)                // Check to see if the frequency has changed. If so, update everything.
  {
    UpdateDisplay();
    SendFrequency();
    oldfreq = freq;
  }

  if (digitalRead(pushPin) == LOW)    // Update cursor, but also stop it from flickering
  {
    delay(10);
    while (digitalRead(pushPin) == LOW)
    {
      if (updatedisplay == 1)
      {
        UpdateDisplay();
        updatedisplay = 0;
      }
    }
    delay(50);
  }
}


void Turn_On_Receiver()
{
  AudioNoInterrupts();
  audioShield.inputSelect(AUDIO_INPUT_LINEIN);
  audioShield.lineInLevel(5);                                               // Default is 5
  audioShield.unmuteHeadphone();
  RX_Hilbert_Plus_45.begin(Hilbert_Plus_45_Coeffs, NO_HILBERT_COEFFS);
  RX_Hilbert_Minus_45.begin(Hilbert_Minus_45_Coeffs, NO_HILBERT_COEFFS);

  if (freq <= 9999999)          // LSB
  {
    RX_Summer.gain(0, 1);
    RX_Summer.gain(1, -1);
  }
  if (freq > 9999999)           // USB
  {
    RX_Summer.gain(0, 1);
    RX_Summer.gain(1, 1);
  }

  AudioInterrupts();
}


// Interrupt routines
void ISRrotAChange()
{
  if (digitalRead(rotAPin))
  {
    rotAval = 1;
    UpdateRot();
  }
  else
  {
    rotAval = 0;
    UpdateRot();
  }
}


void ISRrotBChange()
{
  if (digitalRead(rotBPin))
  {
    rotBval = 1;
    UpdateRot();
  }
  else
  {
    rotBval = 0;
    UpdateRot();
  }
}


void UpdateRot()
{
  switch (rotState)
  {

    case 0:                                         // Idle state, look for direction
      if (!rotBval)
        rotState = 1;                               // CW 1
      if (!rotAval)
        rotState = 11;                              // CCW 1
      break;

    case 1:                                         // CW, wait for A low while B is low
      if (!rotBval)
      {
        if (!rotAval)
        {
          // either increment radixindex or freq
          if (digitalRead(pushPin) == LOW)
          {
            updatedisplay = 1;
            if (radix == 1000000)
              radix = 100000;
            else if (radix == 100000)
              radix = 10000;
            else if (radix == 10000)
              radix = 1000;
            else if (radix == 1000)
              radix = 100;
            else if (radix == 100)
              radix = 10;
            else if (radix == 10)
              radix = 1;
            else
              radix = 1000000;
          }
          else
          {
            freq = (freq + radix);
            if (freq > bandEnd)
              freq = bandEnd;
          }
          rotState = 2;                             // CW 2
        }
      }
      else if (rotAval)
        rotState = 0;                               // It was just a glitch on B, go back to start
      break;

    case 2:                                         // CW, wait for B high
      if (rotBval)
        rotState = 3;                               // CW 3
      break;

    case 3:                                         // CW, wait for A high
      if (rotAval)
        rotState = 0;                               // back to idle (detent) state
      break;

    case 11:                                        // CCW, wait for B low while A is low
      if (!rotAval)
      {
        if (!rotBval)
        {
          // either decrement radixindex or freq
          if (digitalRead(pushPin) == LOW)
          {
            updatedisplay = 1;
            if (radix == 1)
              radix = 10;
            else if (radix == 10)
              radix = 100;
            else if (radix == 100)
              radix = 1000;
            else if (radix == 1000)
              radix = 10000;
            else if (radix == 10000)
              radix = 100000;
            else if (radix == 100000)
              radix = 1000000;
            else
              radix = 1;
          }
          else
          {
            freq = (freq - radix);
            if (freq < bandStart)
              freq = bandStart;
          }
          rotState = 12;                            // CCW 2
        }
      }
      else if (rotBval)
        rotState = 0;                               // It was just a glitch on A, go back to start
      break;

    case 12:                                        // CCW, wait for A high
      if (rotAval)
        rotState = 13;                              // CCW 3
      break;

    case 13:                                        // CCW, wait for B high
      if (rotBval)
        rotState = 0;                               // back to idle (detent) state
      break;
  }
}


void UpdateDisplay()
{
  lcd.cursor();                                     // Turn on the cursor
  lcd.setCursor(0, 0);
  lcd.print("        ");
  lcd.setCursor(0, 0);
  lcd.print(freq);
  lcd.setCursor(10, 0);
  lcd.print("ZL2CTM");

  lcd.setCursor(0, 1);
  lcd.print("        ");
  lcd.setCursor(0, 1);

  if (freq > 9999999)
  {
    if (radix == 1)
      lcd.setCursor(7, 0);
    if (radix == 10)
      lcd.setCursor(6, 0);
    if (radix == 100)
      lcd.setCursor(5, 0);
    if (radix == 1000)
      lcd.setCursor(4, 0);
    if (radix == 10000)
      lcd.setCursor(3, 0);
    if (radix == 100000)
      lcd.setCursor(2, 0);
    if (radix == 1000000)
      lcd.setCursor(1, 0);

  }
  if (freq <= 9999999)
  {
    if (radix == 1)
      lcd.setCursor(6, 0);
    if (radix == 10)
      lcd.setCursor(5, 0);
    if (radix == 100)
      lcd.setCursor(4, 0);
    if (radix == 1000)
      lcd.setCursor(3, 0);
    if (radix == 10000)
      lcd.setCursor(2, 0);
    if (radix == 100000)
      lcd.setCursor(1, 0);
    if (radix == 1000000)
      lcd.setCursor(0, 0);
  }
}


void SendFrequency()
{
  si5351.set_freq((freq * 4) * 100ULL, SI5351_PLL_FIXED, SI5351_CLK0);

}

 ***************************************************************

 Transmit Test Configuration






Transmit Test Code 

 Note, the formatting has been messed up from cutting and pasting. Use auto format after pasting into the Arduino IDE) 
// Libraries
#include <Wire.h>                          // I2C comms library
#include <si5351.h>                        // Si5351Jason library
#include <LiquidCrystal_I2C.h>             // LCD library
#include <Audio.h>                         // Teensy audio library

// Number of Filter Coefficients
#define NO_HILBERT_COEFFS 70               // Used to define the Hilbert transform filter arrays. More typical than 'const int'.

// Define Constants and Vaviables
static const long bandStart = 1000000;     // start of HF band
static const long bandEnd =   30000000;    // end of HF band
static const long bandInit =  3690000;     // where to initially set the frequency
//static const long bandInit =  14190000;  // where to initially set the frequency
volatile long oldfreq = 0;
volatile long freq = bandInit ;
volatile long radix = 1000;                // how much to change the frequency by clicking the rotary encoder will change this.
volatile int updatedisplay = 0;

static const int Mic_Gain = 0;            // Range is 0-63dB.
static const int Lineout_Gain = 20;        // Range is 13-31. 13 = 3.16 Vp-p, 31 = 1.16 Vp-p

// Rotary Encoder
static const int pushPin = 39;
static const int rotBPin = 36;
static const int rotAPin = 35;
volatile int rotState = 0;
volatile int rotAval = 1;
volatile int rotBval = 1;
volatile int rotAcc = 0;


// Iowa Hills Hilbert transform filter coefficients
const short Hilbert_Plus_45_Coeffs[NO_HILBERT_COEFFS] = {
  (short)(32768 * -0.000287988910943357),
  (short)(32768 * -0.000383511439791303),
  (short)(32768 * -0.000468041804899774),
  (short)(32768 * -0.000529324432676899),
  (short)(32768 * -0.000569479602046985),
  (short)(32768 * -0.000616670267768531),
  (short)(32768 * -0.000731530748681977),
  (short)(32768 * -0.001002372095321225),
  (short)(32768 * -0.001525299390682192),
  (short)(32768 * -0.002370114347025230),
  (short)(32768 * -0.003539247773172147),
  (short)(32768 * -0.004932965382552984),
  (short)(32768 * -0.006337182914262393),
  (short)(32768 * -0.007448193692118567),
  (short)(32768 * -0.007940501940620482),
  (short)(32768 * -0.007570802072162988),
  (short)(32768 * -0.006296120449841751),
  (short)(32768 * -0.004371955618154949),
  (short)(32768 * -0.002391875073164555),
  (short)(32768 * -0.001236984700413469),
  (short)(32768 * -0.001922560128827416),
  (short)(32768 * -0.005356720327533458),
  (short)(32768 * -0.012055656297010635),
  (short)(32768 * -0.021882952959947619),
  (short)(32768 * -0.033888748300090733),
  (short)(32768 * -0.046312736456333638),
  (short)(32768 * -0.056783367797647665),
  (short)(32768 * -0.062699937453677912),
  (short)(32768 * -0.061735375084135742),
  (short)(32768 * -0.052358513976237808),
  (short)(32768 * -0.034257179158167443),
  (short)(32768 * -0.008554500746482946),
  (short)(32768 * 0.022249911747384360),
  (short)(32768 * 0.054622962942346594),
  (short)(32768 * 0.084568844473140448),
  (short)(32768 * 0.108316122839950818),
  (short)(32768 * 0.122979341462627859),
  (short)(32768 * 0.127056096658453188),
  (short)(32768 * 0.120656295327679283),
  (short)(32768 * 0.105420364259485699),
  (short)(32768 * 0.084152608145489444),
  (short)(32768 * 0.060257510644444748),
  (short)(32768 * 0.037105711921879434),
  (short)(32768 * 0.017464092086704748),
  (short)(32768 * 0.003100559033325746),
  (short)(32768 * -0.005373489802481697),
  (short)(32768 * -0.008418211280310166),
  (short)(32768 * -0.007286730644726664),
  (short)(32768 * -0.003638388931163832),
  (short)(32768 * 0.000858330713630433),
  (short)(32768 * 0.004847436504682235),
  (short)(32768 * 0.007476399317750315),
  (short)(32768 * 0.008440227567663121),
  (short)(32768 * 0.007898970420636600),
  (short)(32768 * 0.006314366257036837),
  (short)(32768 * 0.004261033495040515),
  (short)(32768 * 0.002261843500794377),
  (short)(32768 * 0.000680212977485724),
  (short)(32768 * -0.000319493110301691),
  (short)(32768 * -0.000751893569425181),
  (short)(32768 * -0.000752248417868501),
  (short)(32768 * -0.000505487955986662),
  (short)(32768 * -0.000184645628631330),
  (short)(32768 * 0.000087913008490067),
  (short)(32768 * 0.000253106348867209),
  (short)(32768 * 0.000306473486382603),
  (short)(32768 * 0.000277637042003169),
  (short)(32768 * 0.000207782317481292),
  (short)(32768 * 0.000132446796990356),
  (short)(32768 * 0.000072894261560354)
};

// Iowa Hills Hilbert transform filter coefficients
const short Hilbert_Minus_45_Coeffs[NO_HILBERT_COEFFS] = {
  (short)(32768 * -0.000072894261560345),
  (short)(32768 * -0.000132446796990344),
  (short)(32768 * -0.000207782317481281),
  (short)(32768 * -0.000277637042003168),
  (short)(32768 * -0.000306473486382623),
  (short)(32768 * -0.000253106348867259),
  (short)(32768 * -0.000087913008490148),
  (short)(32768 * 0.000184645628631233),
  (short)(32768 * 0.000505487955986583),
  (short)(32768 * 0.000752248417868491),
  (short)(32768 * 0.000751893569425298),
  (short)(32768 * 0.000319493110301983),
  (short)(32768 * -0.000680212977485245),
  (short)(32768 * -0.002261843500793748),
  (short)(32768 * -0.004261033495039842),
  (short)(32768 * -0.006314366257036280),
  (short)(32768 * -0.007898970420636345),
  (short)(32768 * -0.008440227567663343),
  (short)(32768 * -0.007476399317751102),
  (short)(32768 * -0.004847436504683540),
  (short)(32768 * -0.000858330713632029),
  (short)(32768 * 0.003638388931162351),
  (short)(32768 * 0.007286730644725833),
  (short)(32768 * 0.008418211280310565),
  (short)(32768 * 0.005373489802483816),
  (short)(32768 * -0.003100559033321630),
  (short)(32768 * -0.017464092086698697),
  (short)(32768 * -0.037105711921871905),
  (short)(32768 * -0.060257510644436532),
  (short)(32768 * -0.084152608145481672),
  (short)(32768 * -0.105420364259479538),
  (short)(32768 * -0.120656295327675800),
  (short)(32768 * -0.127056096658453216),
  (short)(32768 * -0.122979341462631633),
  (short)(32768 * -0.108316122839958146),
  (short)(32768 * -0.084568844473150454),
  (short)(32768 * -0.054622962942358168),
  (short)(32768 * -0.022249911747396132),
  (short)(32768 * 0.008554500746472333),
  (short)(32768 * 0.034257179158159054),
  (short)(32768 * 0.052358513976232306),
  (short)(32768 * 0.061735375084133286),
  (short)(32768 * 0.062699937453678217),
  (short)(32768 * 0.056783367797650072),
  (short)(32768 * 0.046312736456337288),
  (short)(32768 * 0.033888748300094730),
  (short)(32768 * 0.021882952959951244),
  (short)(32768 * 0.012055656297013388),
  (short)(32768 * 0.005356720327535105),
  (short)(32768 * 0.001922560128828006),
  (short)(32768 * 0.001236984700413229),
  (short)(32768 * 0.002391875073163812),
  (short)(32768 * 0.004371955618154038),
  (short)(32768 * 0.006296120449840938),
  (short)(32768 * 0.007570802072162439),
  (short)(32768 * 0.007940501940620253),
  (short)(32768 * 0.007448193692118624),
  (short)(32768 * 0.006337182914262643),
  (short)(32768 * 0.004932965382553323),
  (short)(32768 * 0.003539247773172483),
  (short)(32768 * 0.002370114347025498),
  (short)(32768 * 0.001525299390682370),
  (short)(32768 * 0.001002372095321316),
  (short)(32768 * 0.000731530748682004),
  (short)(32768 * 0.000616670267768521),
  (short)(32768 * 0.000569479602046963),
  (short)(32768 * 0.000529324432676881),
  (short)(32768 * 0.000468041804899765),
  (short)(32768 * 0.000383511439791304),
  (short)(32768 * 0.000287988910943362)
};


// Instantiate the Objects
LiquidCrystal_I2C lcd(0x3F, 16, 2);       // Name for the LCD. Set the LCD address to either 0x27 or 0x3F for a 16 chars and 2 line display
Si5351 si5351;                            // Name for the Si5351 DDS
AudioControlSGTL5000    audioShield;      // Name for the Teensy audio CODEC on the audio shield

// Audio shield
AudioInputI2S           audioInput;                                           // Name for the input to the audio shield (either line-in or mic)
AudioOutputI2S          audioOutput;                                          // Name for the output of the audio shield (either headphones or line-out)
// Transmitter
AudioFilterFIR          TX_Hilbert_Plus_45;                                   // Name for the TX +45 Hilbert transform
AudioFilterFIR          TX_Hilbert_Minus_45;                                  // Name for the TX +45 Hilbert transform
AudioMixer4             TX_I_Sideband_Switch;                                 // Name for the sideband switching summer for the I channel

// Audio connections
AudioConnection         patchCord50(audioInput, 0, TX_Hilbert_Plus_45, 0);              // Mic audio to Hilbert transform +45
AudioConnection         patchCord55(audioInput, 0, TX_Hilbert_Minus_45, 0);             // Mic audio to  Hilbert transform -45
AudioConnection         patchCord60(TX_Hilbert_Plus_45, 0, TX_I_Sideband_Switch, 0);    // Hilbert transform +45 to receiver summer
AudioConnection         patchCord65(TX_I_Sideband_Switch, 0, audioOutput, 0);           // Output to the NE612
AudioConnection         patchCord70(TX_Hilbert_Minus_45, 0, audioOutput, 1);            // Output to the NE612


void setup()
{
  // Setup input switches
  pinMode(rotAPin, INPUT);
  pinMode(rotBPin, INPUT);
  pinMode(pushPin, INPUT);
  digitalWrite(rotAPin, HIGH);
  digitalWrite(rotBPin, HIGH);
  digitalWrite(pushPin, HIGH);

  // Setup interrupt pins
  attachInterrupt(digitalPinToInterrupt(rotAPin), ISRrotAChange, CHANGE);
  attachInterrupt(digitalPinToInterrupt(rotBPin), ISRrotBChange, CHANGE);

  // Setup the lcd
  lcd.begin();
  lcd.backlight();

  // Setup the DDS
  si5351.init(SI5351_CRYSTAL_LOAD_8PF, 0);
  si5351.set_pll(SI5351_PLL_FIXED, SI5351_PLLA);
  si5351.drive_strength(SI5351_CLK0, SI5351_DRIVE_8MA);
  si5351.set_freq((freq * 100ULL), SI5351_PLL_FIXED, SI5351_CLK0);

  // Setup the audio shield
  AudioNoInterrupts();
  AudioMemory(16);
  audioShield.enable();
  AudioInterrupts();

  // Setup transceiver mode
  Turn_On_Transmitter();
  UpdateDisplay();
}

void loop()
{
  if (freq != oldfreq)                // Check to see if the frequency has changed. If so, update everything.
  {
    UpdateDisplay();
    SendFrequency();
    oldfreq = freq;
  }

  if (digitalRead(pushPin) == LOW)    // Update cursor, but also stop it from flickering
  {
    delay(10);
    while (digitalRead(pushPin) == LOW)
    {
      if (updatedisplay == 1)
      {
        UpdateDisplay();
        updatedisplay = 0;
      }
    }
    delay(50);
  }
}


void Turn_On_Transmitter()
{
  AudioNoInterrupts();
  audioShield.inputSelect(AUDIO_INPUT_MIC);
  audioShield.micGain(Mic_Gain);                                         
  audioShield.unmuteLineout();                                        // Output to the NE612s
  audioShield.lineOutLevel(Lineout_Gain);                         
  TX_Hilbert_Plus_45.begin(Hilbert_Plus_45_Coeffs, NO_HILBERT_COEFFS);
  TX_Hilbert_Minus_45.begin(Hilbert_Minus_45_Coeffs, NO_HILBERT_COEFFS);

  if (freq <= 9999999)          // LSB
  {
    TX_I_Sideband_Switch.gain(0, 1);
  }
  if (freq > 9999999)           // USB
  {
    TX_I_Sideband_Switch.gain(0, -1);
  }

  AudioInterrupts();
}


// Interrupt routines
void ISRrotAChange()
{
  if (digitalRead(rotAPin))
  {
    rotAval = 1;
    UpdateRot();
  }
  else
  {
    rotAval = 0;
    UpdateRot();
  }
}


void ISRrotBChange()
{
  if (digitalRead(rotBPin))
  {
    rotBval = 1;
    UpdateRot();
  }
  else
  {
    rotBval = 0;
    UpdateRot();
  }
}


void UpdateRot()
{
  switch (rotState)
  {

    case 0:                                         // Idle state, look for direction
      if (!rotBval)
        rotState = 1;                               // CW 1
      if (!rotAval)
        rotState = 11;                              // CCW 1
      break;

    case 1:                                         // CW, wait for A low while B is low
      if (!rotBval)
      {
        if (!rotAval)
        {
          // either increment radixindex or freq
          if (digitalRead(pushPin) == LOW)
          {
            updatedisplay = 1;
            if (radix == 1000000)
              radix = 100000;
            else if (radix == 100000)
              radix = 10000;
            else if (radix == 10000)
              radix = 1000;
            else if (radix == 1000)
              radix = 100;
            else if (radix == 100)
              radix = 10;
            else if (radix == 10)
              radix = 1;
            else
              radix = 1000000;
          }
          else
          {
            freq = (freq + radix);
            if (freq > bandEnd)
              freq = bandEnd;
          }
          rotState = 2;                             // CW 2
        }
      }
      else if (rotAval)
        rotState = 0;                               // It was just a glitch on B, go back to start
      break;

    case 2:                                         // CW, wait for B high
      if (rotBval)
        rotState = 3;                               // CW 3
      break;

    case 3:                                         // CW, wait for A high
      if (rotAval)
        rotState = 0;                               // back to idle (detent) state
      break;

    case 11:                                        // CCW, wait for B low while A is low
      if (!rotAval)
      {
        if (!rotBval)
        {
          // either decrement radixindex or freq
          if (digitalRead(pushPin) == LOW)
          {
            updatedisplay = 1;
            if (radix == 1)
              radix = 10;
            else if (radix == 10)
              radix = 100;
            else if (radix == 100)
              radix = 1000;
            else if (radix == 1000)
              radix = 10000;
            else if (radix == 10000)
              radix = 100000;
            else if (radix == 100000)
              radix = 1000000;
            else
              radix = 1;
          }
          else
          {
            freq = (freq - radix);
            if (freq < bandStart)
              freq = bandStart;
          }
          rotState = 12;                            // CCW 2
        }
      }
      else if (rotBval)
        rotState = 0;                               // It was just a glitch on A, go back to start
      break;

    case 12:                                        // CCW, wait for A high
      if (rotAval)
        rotState = 13;                              // CCW 3
      break;

    case 13:                                        // CCW, wait for B high
      if (rotBval)
        rotState = 0;                               // back to idle (detent) state
      break;
  }
}


void UpdateDisplay()
{
  lcd.cursor();                                     // Turn on the cursor
  lcd.setCursor(0, 0);
  lcd.print("        ");
  lcd.setCursor(0, 0);
  lcd.print(freq);
  lcd.setCursor(10, 0);
  lcd.print("ZL2CTM");

  lcd.setCursor(0, 1);
  lcd.print("        ");
  lcd.setCursor(0, 1);

  if (freq > 9999999)
  {
    if (radix == 1)
      lcd.setCursor(7, 0);
    if (radix == 10)
      lcd.setCursor(6, 0);
    if (radix == 100)
      lcd.setCursor(5, 0);
    if (radix == 1000)
      lcd.setCursor(4, 0);
    if (radix == 10000)
      lcd.setCursor(3, 0);
    if (radix == 100000)
      lcd.setCursor(2, 0);
    if (radix == 1000000)
      lcd.setCursor(1, 0);

  }
  if (freq <= 9999999)
  {
    if (radix == 1)
      lcd.setCursor(6, 0);
    if (radix == 10)
      lcd.setCursor(5, 0);
    if (radix == 100)
      lcd.setCursor(4, 0);
    if (radix == 1000)
      lcd.setCursor(3, 0);
    if (radix == 10000)
      lcd.setCursor(2, 0);
    if (radix == 100000)
      lcd.setCursor(1, 0);
    if (radix == 1000000)
      lcd.setCursor(0, 0);
  }
}


void SendFrequency()
{
  si5351.set_freq((freq * 4) * 100ULL, SI5351_PLL_FIXED, SI5351_CLK0);

}

****************************************************************

 Final Code (as is).

  // Libraries
#include <Wire.h>                          // I2C comms library
#include <si5351.h>                        // Si5351Jason library
#include <LiquidCrystal_I2C.h>             // LCD library
#include <Audio.h>                         // Teensy audio library

// Number of Filter Coefficients
#define NO_HILBERT_COEFFS 70               // Used to define the Hilbert transform filter arrays. More typical than 'const int'.

// Define Constants and Vaviables
static const long bandStart = 1000000;     // start of HF band
static const long bandEnd =   30000000;    // end of HF band
static const long bandInit =  3690000;     // where to initially set the frequency
volatile long oldfreq = 0;
volatile long freq = bandInit ;
volatile long radix = 1000;                // how much to change the frequency. Pushing the rotary encoder switch will change this.
volatile int updatedisplay = 0;
volatile int mode = 0;                     // 1 = LSB, 0 = USB
volatile int oldmode = 0;
volatile int Receive = 0;                  // 0 = Receiver off, 1 = Receiver on
volatile int Transmit = 0;                 // 0 = Transmitter off, 1 = Transmitter on

// Audio panel gains
static const int Mic_Gain = 0;             // Range is 0-63dB.
static const int Lineout_Gain = 20;        // Range is 13-31. 13 = 3.16 Vp-p, 31 = 1.16 Vp-p
static const int Linein_Gain = 5;          // Range is 0-15. 0 = 3.12 Vp-p, 15 = 0.24 Vp-p. Default = 5

// Rotary Encoder
static const int EncoderPushButton = 39;
static const int rotBPin = 36;
static const int rotAPin = 35;
static const int ModeSwitch = 24;
static const int PTTSwitch = 25;
volatile int rotState = 0;
volatile int rotAval = 1;
volatile int rotBval = 1;
volatile int rotAcc = 0;

// Iowa Hills Hilbert transform filter coefficients
const short Hilbert_Plus_45_Coeffs[NO_HILBERT_COEFFS] = {
  (short)(32768 * -0.000287988910943357),
  (short)(32768 * -0.000383511439791303),
  (short)(32768 * -0.000468041804899774),
  (short)(32768 * -0.000529324432676899),
  (short)(32768 * -0.000569479602046985),
  (short)(32768 * -0.000616670267768531),
  (short)(32768 * -0.000731530748681977),
  (short)(32768 * -0.001002372095321225),
  (short)(32768 * -0.001525299390682192),
  (short)(32768 * -0.002370114347025230),
  (short)(32768 * -0.003539247773172147),
  (short)(32768 * -0.004932965382552984),
  (short)(32768 * -0.006337182914262393),
  (short)(32768 * -0.007448193692118567),
  (short)(32768 * -0.007940501940620482),
  (short)(32768 * -0.007570802072162988),
  (short)(32768 * -0.006296120449841751),
  (short)(32768 * -0.004371955618154949),
  (short)(32768 * -0.002391875073164555),
  (short)(32768 * -0.001236984700413469),
  (short)(32768 * -0.001922560128827416),
  (short)(32768 * -0.005356720327533458),
  (short)(32768 * -0.012055656297010635),
  (short)(32768 * -0.021882952959947619),
  (short)(32768 * -0.033888748300090733),
  (short)(32768 * -0.046312736456333638),
  (short)(32768 * -0.056783367797647665),
  (short)(32768 * -0.062699937453677912),
  (short)(32768 * -0.061735375084135742),
  (short)(32768 * -0.052358513976237808),
  (short)(32768 * -0.034257179158167443),
  (short)(32768 * -0.008554500746482946),
  (short)(32768 * 0.022249911747384360),
  (short)(32768 * 0.054622962942346594),
  (short)(32768 * 0.084568844473140448),
  (short)(32768 * 0.108316122839950818),
  (short)(32768 * 0.122979341462627859),
  (short)(32768 * 0.127056096658453188),
  (short)(32768 * 0.120656295327679283),
  (short)(32768 * 0.105420364259485699),
  (short)(32768 * 0.084152608145489444),
  (short)(32768 * 0.060257510644444748),
  (short)(32768 * 0.037105711921879434),
  (short)(32768 * 0.017464092086704748),
  (short)(32768 * 0.003100559033325746),
  (short)(32768 * -0.005373489802481697),
  (short)(32768 * -0.008418211280310166),
  (short)(32768 * -0.007286730644726664),
  (short)(32768 * -0.003638388931163832),
  (short)(32768 * 0.000858330713630433),
  (short)(32768 * 0.004847436504682235),
  (short)(32768 * 0.007476399317750315),
  (short)(32768 * 0.008440227567663121),
  (short)(32768 * 0.007898970420636600),
  (short)(32768 * 0.006314366257036837),
  (short)(32768 * 0.004261033495040515),
  (short)(32768 * 0.002261843500794377),
  (short)(32768 * 0.000680212977485724),
  (short)(32768 * -0.000319493110301691),
  (short)(32768 * -0.000751893569425181),
  (short)(32768 * -0.000752248417868501),
  (short)(32768 * -0.000505487955986662),
  (short)(32768 * -0.000184645628631330),
  (short)(32768 * 0.000087913008490067),
  (short)(32768 * 0.000253106348867209),
  (short)(32768 * 0.000306473486382603),
  (short)(32768 * 0.000277637042003169),
  (short)(32768 * 0.000207782317481292),
  (short)(32768 * 0.000132446796990356),
  (short)(32768 * 0.000072894261560354)
};

// Iowa Hills Hilbert transform filter coefficients
const short Hilbert_Minus_45_Coeffs[NO_HILBERT_COEFFS] = {
  (short)(32768 * -0.000072894261560345),
  (short)(32768 * -0.000132446796990344),
  (short)(32768 * -0.000207782317481281),
  (short)(32768 * -0.000277637042003168),
  (short)(32768 * -0.000306473486382623),
  (short)(32768 * -0.000253106348867259),
  (short)(32768 * -0.000087913008490148),
  (short)(32768 * 0.000184645628631233),
  (short)(32768 * 0.000505487955986583),
  (short)(32768 * 0.000752248417868491),
  (short)(32768 * 0.000751893569425298),
  (short)(32768 * 0.000319493110301983),
  (short)(32768 * -0.000680212977485245),
  (short)(32768 * -0.002261843500793748),
  (short)(32768 * -0.004261033495039842),
  (short)(32768 * -0.006314366257036280),
  (short)(32768 * -0.007898970420636345),
  (short)(32768 * -0.008440227567663343),
  (short)(32768 * -0.007476399317751102),
  (short)(32768 * -0.004847436504683540),
  (short)(32768 * -0.000858330713632029),
  (short)(32768 * 0.003638388931162351),
  (short)(32768 * 0.007286730644725833),
  (short)(32768 * 0.008418211280310565),
  (short)(32768 * 0.005373489802483816),
  (short)(32768 * -0.003100559033321630),
  (short)(32768 * -0.017464092086698697),
  (short)(32768 * -0.037105711921871905),
  (short)(32768 * -0.060257510644436532),
  (short)(32768 * -0.084152608145481672),
  (short)(32768 * -0.105420364259479538),
  (short)(32768 * -0.120656295327675800),
  (short)(32768 * -0.127056096658453216),
  (short)(32768 * -0.122979341462631633),
  (short)(32768 * -0.108316122839958146),
  (short)(32768 * -0.084568844473150454),
  (short)(32768 * -0.054622962942358168),
  (short)(32768 * -0.022249911747396132),
  (short)(32768 * 0.008554500746472333),
  (short)(32768 * 0.034257179158159054),
  (short)(32768 * 0.052358513976232306),
  (short)(32768 * 0.061735375084133286),
  (short)(32768 * 0.062699937453678217),
  (short)(32768 * 0.056783367797650072),
  (short)(32768 * 0.046312736456337288),
  (short)(32768 * 0.033888748300094730),
  (short)(32768 * 0.021882952959951244),
  (short)(32768 * 0.012055656297013388),
  (short)(32768 * 0.005356720327535105),
  (short)(32768 * 0.001922560128828006),
  (short)(32768 * 0.001236984700413229),
  (short)(32768 * 0.002391875073163812),
  (short)(32768 * 0.004371955618154038),
  (short)(32768 * 0.006296120449840938),
  (short)(32768 * 0.007570802072162439),
  (short)(32768 * 0.007940501940620253),
  (short)(32768 * 0.007448193692118624),
  (short)(32768 * 0.006337182914262643),
  (short)(32768 * 0.004932965382553323),
  (short)(32768 * 0.003539247773172483),
  (short)(32768 * 0.002370114347025498),
  (short)(32768 * 0.001525299390682370),
  (short)(32768 * 0.001002372095321316),
  (short)(32768 * 0.000731530748682004),
  (short)(32768 * 0.000616670267768521),
  (short)(32768 * 0.000569479602046963),
  (short)(32768 * 0.000529324432676881),
  (short)(32768 * 0.000468041804899765),
  (short)(32768 * 0.000383511439791304),
  (short)(32768 * 0.000287988910943362)
};


// Instantiate the Objects
LiquidCrystal_I2C lcd(0x3F, 16, 2);       // Name for the LCD. Set the LCD address to either 0x27 or 0x3F for a 16 chars and 2 line display
Si5351 si5351;                            // Name for the Si5351 DDS
AudioControlSGTL5000    audioShield;      // Name for the Teensy audio CODEC on the audio shield

// Audio shield
AudioInputI2S           audioInput;                                           // Name for the input to the audio shield (either line-in or mic)
AudioOutputI2S          audioOutput;                                          // Name for the output of the audio shield (either headphones or line-out)
// Receiver
AudioFilterFIR          RX_Hilbert_Plus_45;                                   // Name for the RX +45 Hilbert transform
AudioFilterFIR          RX_Hilbert_Minus_45;                                  // Name for the RX +45 Hilbert transform
AudioMixer4             RX_Summer;                                            // Name for the RX summer
// Transmitter
AudioFilterFIR          TX_Hilbert_Plus_45;                                   // Name for the TX +45 Hilbert transform
AudioFilterFIR          TX_Hilbert_Minus_45;                                  // Name for the TX +45 Hilbert transform
AudioMixer4             TX_I_Sideband_Switch;                                 // Name for the sideband switching summer for the I channel

// Audio connections
AudioConnection         patchCord5(audioInput, 0, RX_Hilbert_Plus_45, 0);               // Left channel in Hilbert transform +45
AudioConnection         patchCord10(audioInput, 1, RX_Hilbert_Minus_45, 0);             // Right channel in Hilbert transform -45
AudioConnection         patchCord15(RX_Hilbert_Plus_45, 0, RX_Summer, 0);               // Hilbert transform +45 to receiver summer
AudioConnection         patchCord20(RX_Hilbert_Minus_45, 0, RX_Summer, 1);              // Hilbert transform -45 to receiver summer
AudioConnection         patchCord25(RX_Summer, 0, audioOutput, 0);                      // Receiver summer to receiver LPF

AudioConnection         patchCord50(audioInput, 0, TX_Hilbert_Plus_45, 0);              // Mic audio to Hilbert transform +45
AudioConnection         patchCord55(audioInput, 0, TX_Hilbert_Minus_45, 0);             // Mic audio to  Hilbert transform -45
AudioConnection         patchCord60(TX_Hilbert_Plus_45, 0, TX_I_Sideband_Switch, 0);    // Hilbert transform +45 to receiver summer
AudioConnection         patchCord65(TX_I_Sideband_Switch, 0, audioOutput, 0);           // Output to the NE612
AudioConnection         patchCord70(TX_Hilbert_Minus_45, 0, audioOutput, 1);            // Output to the NE612


void setup()
{
  // Setup input switches
  pinMode(rotAPin, INPUT);
  pinMode(rotBPin, INPUT);
  pinMode(EncoderPushButton, INPUT);
  pinMode(ModeSwitch, INPUT);
  pinMode(PTTSwitch, INPUT);
  digitalWrite(rotAPin, HIGH);
  digitalWrite(rotBPin, HIGH);
  digitalWrite(EncoderPushButton, HIGH);
  digitalWrite(ModeSwitch, HIGH);
  digitalWrite(PTTSwitch, HIGH);

  // Setup interrupt pins
  attachInterrupt(digitalPinToInterrupt(rotAPin), ISRrotAChange, CHANGE);
  attachInterrupt(digitalPinToInterrupt(rotBPin), ISRrotBChange, CHANGE);

  // Setup the lcd
  lcd.begin();
  lcd.backlight();
  lcd.cursor();

  // Setup the DDS
  si5351.init(SI5351_CRYSTAL_LOAD_8PF, 0);
  si5351.set_pll(SI5351_PLL_FIXED, SI5351_PLLA);
  si5351.drive_strength(SI5351_CLK0, SI5351_DRIVE_8MA);
  si5351.set_freq((freq * 4) * 100ULL, SI5351_PLL_FIXED, SI5351_CLK0);

  // Setup the audio shield
  AudioNoInterrupts();
  AudioMemory(16);
  audioShield.enable();
  AudioInterrupts();

  // Setup transceiver mode
  Turn_On_Receiver();
  Turn_Off_Transmitter();
  UpdateDisplay();
}

void loop()
{
  if (freq != oldfreq)                // Check to see if the frequency has changed. If so, update everything.
  {
    UpdateDisplay();
    SendFrequency();
    oldfreq = freq;
  }

  if (digitalRead(EncoderPushButton) == LOW)    // Update cursor, but also stop it from flickering
  {
    delay(50);
    while (digitalRead(EncoderPushButton) == LOW)
    {
      if (updatedisplay == 1)
      {
        UpdateDisplay();
        updatedisplay = 0;
      }
    }
    delay(50);
  }

  if (digitalRead(ModeSwitch) == LOW)
    mode = 1;                               // LSB
  else
    mode = 0;                               // USB

  if (mode != oldmode)                      // Only update the display on mode change
  {
    UpdateMode();
    UpdateDisplay();
    oldmode = mode;
  }

  if ((digitalRead(PTTSwitch) == 0) && (Receive == 1))      // Transmit
  {
    delay(50);
    if ((digitalRead(PTTSwitch) == 0) && (Receive == 1))
    {
      Turn_Off_Receiver();
      Turn_On_Transmitter();
    }
    delay(50);
  }

  if ((digitalRead(PTTSwitch) == 1) && (Transmit == 1))     // Receive
  {
    delay(50);
    if ((digitalRead(PTTSwitch) == 1) && (Transmit  == 1))
    {
      Turn_Off_Transmitter();
      Turn_On_Receiver();
    }
    delay(50);
  }
}


void Turn_On_Receiver()
{
  AudioNoInterrupts();
  audioShield.inputSelect(AUDIO_INPUT_LINEIN);
  audioShield.lineInLevel(Linein_Gain);
  audioShield.unmuteHeadphone();                                        // Output to the audio amplifier
  audioShield.volume(0.8);
  RX_Hilbert_Plus_45.begin(Hilbert_Plus_45_Coeffs, NO_HILBERT_COEFFS);
  RX_Hilbert_Minus_45.begin(Hilbert_Minus_45_Coeffs, NO_HILBERT_COEFFS);
  UpdateMode();
  AudioInterrupts();
  Receive = 1;
}


void Turn_Off_Receiver()
{
  AudioNoInterrupts();
  audioShield.muteHeadphone();
  RX_Hilbert_Plus_45.end();
  RX_Hilbert_Minus_45.end();
  AudioInterrupts();
  Receive = 0;
}


void Turn_On_Transmitter()
{
  AudioNoInterrupts();
  audioShield.inputSelect(AUDIO_INPUT_MIC);
  audioShield.micGain(Mic_Gain);
  audioShield.unmuteLineout();                                        // Output to the NE612s
  audioShield.lineOutLevel(Lineout_Gain);
  TX_Hilbert_Plus_45.begin(Hilbert_Plus_45_Coeffs, NO_HILBERT_COEFFS);
  TX_Hilbert_Minus_45.begin(Hilbert_Minus_45_Coeffs, NO_HILBERT_COEFFS);
  UpdateMode();
  AudioInterrupts();
  Transmit = 1;
}


void Turn_Off_Transmitter()
{
  AudioNoInterrupts();
  audioShield.muteLineout();
  TX_Hilbert_Plus_45.end();
  TX_Hilbert_Minus_45.end();
  AudioInterrupts();
  Transmit = 0;
}


void UpdateMode()
{
  if (Receive == 1)
  {
    if (mode == 1)                                  // LSB
      RX_Summer.gain(1, -1);
    if (mode == 0)                                  // USB
      RX_Summer.gain(1, 1);
  }

  if (Transmit == 1)
  {
    if (mode == 1)                                  // LSB
      TX_I_Sideband_Switch.gain(0, 1);
    if (mode == 0)                                  // USB
      TX_I_Sideband_Switch.gain(0, -1);
  }
}


// Interrupt routines
void ISRrotAChange()
{
  if (digitalRead(rotAPin))
  {
    rotAval = 1;
    UpdateRot();
  }
  else
  {
    rotAval = 0;
    UpdateRot();
  }
}


void ISRrotBChange()
{
  if (digitalRead(rotBPin))
  {
    rotBval = 1;
    UpdateRot();
  }
  else
  {
    rotBval = 0;
    UpdateRot();
  }
}


void UpdateRot()
{
  switch (rotState)
  {

    case 0:                                         // Idle state, look for direction
      if (!rotBval)
        rotState = 1;                               // CW 1
      if (!rotAval)
        rotState = 11;                              // CCW 1
      break;

    case 1:                                         // CW, wait for A low while B is low
      if (!rotBval)
      {
        if (!rotAval)
        {
          // either increment radixindex or freq
          if (digitalRead(EncoderPushButton) == LOW)
          {
            updatedisplay = 1;
            if (radix == 1000000)
              radix = 100000;
            else if (radix == 100000)
              radix = 10000;
            else if (radix == 10000)
              radix = 1000;
            else if (radix == 1000)
              radix = 100;
            else if (radix == 100)
              radix = 10;
            else if (radix == 10)
              radix = 1;
            else
              radix = 1000000;
          }
          else
          {
            freq = (freq + radix);
            if (freq > bandEnd)
              freq = bandEnd;
          }
          rotState = 2;                             // CW 2
        }
      }
      else if (rotAval)
        rotState = 0;                               // It was just a glitch on B, go back to start
      break;

    case 2:                                         // CW, wait for B high
      if (rotBval)
        rotState = 3;                               // CW 3
      break;

    case 3:                                         // CW, wait for A high
      if (rotAval)
        rotState = 0;                               // back to idle (detent) state
      break;

    case 11:                                        // CCW, wait for B low while A is low
      if (!rotAval)
      {
        if (!rotBval)
        {
          // either decrement radixindex or freq
          if (digitalRead(EncoderPushButton) == LOW)
          {
            updatedisplay = 1;
            if (radix == 1)
              radix = 10;
            else if (radix == 10)
              radix = 100;
            else if (radix == 100)
              radix = 1000;
            else if (radix == 1000)
              radix = 10000;
            else if (radix == 10000)
              radix = 100000;
            else if (radix == 100000)
              radix = 1000000;
            else
              radix = 1;
          }
          else
          {
            freq = (freq - radix);
            if (freq < bandStart)
              freq = bandStart;
          }
          rotState = 12;                            // CCW 2
        }
      }
      else if (rotBval)
        rotState = 0;                               // It was just a glitch on A, go back to start
      break;

    case 12:                                        // CCW, wait for A high
      if (rotAval)
        rotState = 13;                              // CCW 3
      break;

    case 13:                                        // CCW, wait for B high
      if (rotBval)
        rotState = 0;                               // back to idle (detent) state
      break;
  }
}


void UpdateDisplay()
{
  lcd.setCursor(0, 0);
  lcd.print(freq);

  lcd.setCursor(10, 0);
  lcd.print("ZL2CTM");

  lcd.setCursor(0, 1);
  if (mode == 1)
    lcd.print("LSB");
  else
    lcd.print("USB");

  if (freq > 9999999)
  {
    if (radix == 1)
      lcd.setCursor(7, 0);
    if (radix == 10)
      lcd.setCursor(6, 0);
    if (radix == 100)
      lcd.setCursor(5, 0);
    if (radix == 1000)
      lcd.setCursor(4, 0);
    if (radix == 10000)
      lcd.setCursor(3, 0);
    if (radix == 100000)
      lcd.setCursor(2, 0);
    if (radix == 1000000)
      lcd.setCursor(1, 0);
  }
  if (freq <= 9999999)
  {
    if (radix == 1)
      lcd.setCursor(6, 0);
    if (radix == 10)
      lcd.setCursor(5, 0);
    if (radix == 100)
      lcd.setCursor(4, 0);
    if (radix == 1000)
      lcd.setCursor(3, 0);
    if (radix == 10000)
      lcd.setCursor(2, 0);
    if (radix == 100000)
      lcd.setCursor(1, 0);
    if (radix == 1000000)
      lcd.setCursor(0, 0);
  }
}


void SendFrequency()
{
  si5351.set_freq((freq * 4) * 100ULL, SI5351_PLL_FIXED, SI5351_CLK0);
}














Posted by at
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36 comments:

  1. andykv5921 March 2018 at 13:20

    Charlie, thanks a lot for the great video and explanation of the SDR theory and practice, looking forward for future video! 73! UT9UF

    ReplyDelete
  2. Charlie Morris, ZL2CTM21 March 2018 at 19:27

    Cheers Andrey. My intent is to explain things in the videos and not here. My typing is waaaaay too slow!

    73s
    Charlie ZL2CTM

    ReplyDelete
  3. Jason28 March 2018 at 18:50

    Great job with the videos as always! I wanted to ask if you've done any segments walking through how you peak the BPF? If not, I think that would be a good addition. I know you spoke on the theory of it in the last video, but seeing thebprocthe is very helpful!

    Thx
    W4UNX

    ReplyDelete
    Replies
    1. Charlie Morris, ZL2CTM28 March 2018 at 19:08

      Thanks Jason. I might have tuned a BPF a while back, but I cannot recall which video. I'll certainly look to do it again.
      73s
      Charlie ZL2CTM

      Delete
  4. Bob29 March 2018 at 17:03

    Really enjoying this series Charlie. What is the source of the Liquid_crystal_I2C library?

    ReplyDelete
    Replies
    1. Charlie Morris, ZL2CTM30 March 2018 at 15:17

      Thanks Bob. As for the library, I'm prety sure I got it from here:

      https://github.com/marcoschwartz/LiquidCrystal_I2C

      Charlie

      Delete
    2. Bob8 April 2018 at 10:17

      This comment has been removed by the author.

      Delete
    3. Bob30 May 2018 at 10:52

      Charlie I have a working SSB SDR reciever!! Thx for blazing the trail with this series.

      Delete
  5. Dave3 September 2018 at 14:51

    Have you posted the complete Teensy SDR transceiver code anywhere?

    ReplyDelete
  6. Unknown10 February 2019 at 16:22

    Charlie, thanks for posting this. I was never able to figure out how to use the Teensy Audio board for SDR. It is running just fine now with an rx from qrp-labs using si5351 programmed for quadrature output. Haven't measured opposite side band rejection yet but it so far sounds good.
    Tom, ak2b

    ReplyDelete
    Replies
    1. Charlie Morris, ZL2CTM10 February 2019 at 16:33

      Thanks Tom. I'm pleased you find it useful. The radio is never going to be a FlexRadio replacement, but that was never the aim. It's all about learning and seeing what can be done. Make sure you watch the accompanying videos on YouTube, as I do all the explaining there. My typing is way too slow to do it here. Regards.

      Charlie

      Delete
    2. Unknown11 February 2019 at 09:47

      Maybe it won't be a Flex replacement but I have built radios that SOUND => commercial radios just by paying slight attention to the audio amp. You can get board with any radio except the ones you build yourself :)

      Delete
  7. Unknown11 February 2019 at 09:51

    P.S. I watch all your videos and appreciate the work that goes into them. I like the design explanations a lot!

    ReplyDelete
  8. Rob B26 April 2019 at 15:29

    Very helpful website and video's. A question on your teensy SSB demod Rx above. How much image rejection do you achieve? Cheers, Rob

    ReplyDelete
    Replies
    1. Charlie Morris, ZL2CTM26 April 2019 at 17:04

      Hi Rob. I'm not too sure on that as I didn't do any specific tests. When I changed the tx to the other SB the rx didn't detect it. If I recall Pete Juliano N6QW built it and did some tests. Try his blog. Sorry about that.

      Delete
    2. Rob B27 April 2019 at 04:10

      Hi Charlie, ok, I'll look.
      Just roughly put together an SSB Rx using the teensy3.6/AD9850 DDS/SRA-6 mixers/74HC74 I,Q/J310 front-end + BPF's. It does demod but image looks about 10dB down. I read that I/Q phase and level need trimming to null out image and can be done within the teensy. So far all looks promising. Cheers, Rob

      Delete
    3. Charlie Morris, ZL2CTM27 April 2019 at 13:23

      Thanks Rob. It was certainly interesting to try the Teensy audio library and see what could be done. Thanks again. Charlie

      Delete
    4. robjohnb30 April 2019 at 02:33

      Nice report on IQ demod and importance of IQ level/phase accuracy. I can now achieve >40dB image reject...
      https://www.microwavejournal.com/ext/resources/pdf-downloads/IQTheory-of-Operation.pdf?1336590796

      Rob

      Delete
  9. WA2MZE12 October 2019 at 08:45

    Re-watching these videos and re-reading the blog. I've ordered the Teensy4 version of the Teensy audio board to go with the Teensy4 I recently received. I have the Teensy 3 version of the audio board, but its pinout doesn't match the Teensy 4. This new more powerful Teensy should work out great with an SDR rig.

    ReplyDelete
  10. WA2MZE12 October 2019 at 17:19

    Did you ever post the transceiver code?

    ReplyDelete
  11. Charlie Morris, ZL2CTM1 November 2019 at 15:25

    Yes. It's in the 80/40/20 SDR rig post.

    ReplyDelete
  12. W0CHL12 November 2019 at 19:13

    This comment has been removed by the author.

    ReplyDelete
  13. Unknown7 February 2020 at 13:28

    Hi Charlie,

    Stumbled upon your videos. I've worked through #3 and am moving forward. Very well done. Have a question on your AF amp circuit schematic. You have put pins 6 and 9 as outputs on the NE612's for the Rx audio. Wondering if that's a typo? I thought it would be pin 5 for both of the NE612's based on listening to video #3?

    Thanks,

    Andy ...

    ReplyDelete
    Replies
    1. Charlie Morris, ZL2CTM8 February 2020 at 23:33

      Hi Andy. Yes you are right. I have updated the blog. Pin 5 for NE612 audio. Pin 6 and 9 is for the I and Q drive from the flip flops.

      Delete
  14. Unknown17 May 2020 at 09:53

    Hello Charlie, thanks a lot for taking the effort and time to document and publish so many excellent projects. I was reading about your use of 100E to 1000E audio isolation transformers. There was a time these were abundantly available here but not anymore. Has anyone used toroids instead iron core EI type transformer please. Any guidance will be appreciated. Thanks again, Ashok VU2ASB

    ReplyDelete
    Replies
    1. Charlie Morris, ZL2CTM18 May 2020 at 11:26

      Sorry Ashok. I am not aware of any toroid use. I'd say it would be impractical as you'd need mH of inductance.

      Delete
  15. Unknown18 May 2020 at 09:31

    Hello Charlie, Has anyone explored using the teensy audio module for audio compression please? Thanks. DE VU2ASB Ashok

    ReplyDelete
    Replies
    1. Charlie Morris, ZL2CTM18 May 2020 at 10:57

      Not sure sorry Ashok. Try the Teensy website I know there is a vibrant community.

      Delete
    2. Unknown19 May 2020 at 02:31

      Thanks Charlie, shall let you know if I discover something. 73s Ashok

      Delete
  16. Unknown22 May 2020 at 05:26

    Hi Charlie, I am thinking of using the new and more powerful version 4 of Teensy along with the new audio shield made for it. Do you see an downside of doing so please. Thanks. Ashok VU2ASB

    ReplyDelete
    Replies
    1. Charlie Morris, ZL2CTM22 May 2020 at 12:39

      Hi Ashok. You shouldn't have any problems at all. You might be able to do some more DSP with the extra CPU cycles. I should order one at some stage.

      Delete
  17. W3JDR28 June 2020 at 07:21

    Charlie
    I'm trying to learn how to design filters for the PJRC audio library. Specifically, I'm trying to precisely derive your results designing the Hilbert filter(s) with the Iowa Hills Software. Can you explain:

    1 The Hilbert filter type you used ("phase offset" I assume)
    2 The full set of input parameters
    3 How you converted the coefficients into an array of C Shorts.

    ThanKS
    Joe
    W3JDR

    ReplyDelete
  18. Charlie Morris, ZL2CTM28 June 2020 at 10:09

    Hi Joe. Drop me a line on the QRZ address if you can.
    Charlie ZL2CTM

    ReplyDelete
  19. Rudy13 January 2021 at 21:35

    This comment has been removed by the author.

    ReplyDelete
  20. Rudy13 January 2021 at 21:37

    Hi Charlie , thanks for the explanation in video and this blog , i just learn SDR , i hope i can practice it , i will tell you if i done to made it ,

    Rudy
    de YG3DBO

    ReplyDelete
  21. Charlie Morris, ZL2CTM13 January 2021 at 21:43

    That's great Rudy.

    ReplyDelete

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