====== AD9850 ======
{{:materiel:ad9850:oscillo-ad9850.jpg?500|}}\\
Générateur de signaux sinusoïdaux ou carré.

{{youtube>3lNGF0PJUpk?medium}}

===== Datasheet =====
  * {{:materiel:ad9850:ad9850.pdf|}}
  * 2 sine wave and 2 square wave output (mais tous avec la même fréquence !)
  * AD9850: 0-40MHz
  * After the 20-30MHz frequency harmonics increases, the waveform will be less and less clean
  * Square Wave: 0-1MHz
  * Low-pass filter with 70MHz, so the waveform better than SN
  * Parallel and serial data input can be selected via a jumper
  * DA produced the benchmark pin (PIN12) leads for easy adjustment to do the magnitude of the output waveform Application
  * Comparator reference input voltage generated by the variable resistor, the resistor can be adjusted duty cycle square wave of different
  * Active AD9850 125MHz crystal oscillator modules

===== Avec Arduino =====
  * https://code.google.com/p/ad9850-arduino/
  * http://www.elecfreaks.com/wiki/index.php?title=DDS_Module_-_AD9850
  * http://arduino.alhin.de/index.php?n=67
  * http://nr8o.dhlpilotcentral.com/?p=83
  * http://rockingdlabs.dunmire.org/exercises-experiments/ad-9850-dds-synthesizer
  * http://www.alhin.de/arduino/index.php?n=7
  * http://www.kerrywong.com/2012/11/06/dds-function-generator-build/
  * http://webshed.org/wiki/AD9850_Arduino


==== Connection ====
Il suffit de 6 fils.

| **ARDUINO** | **AD9850** |
| 5V | VCC |
| GND | GND |
| 8 | W_CLK |
| 9 | FQ_UD |
| 10 | DATA |
| 11 | RESET |

{{:materiel:ad9850:arduino-deux-ad9850.jpg?600|}}

==== Code Arduino pour deux modules ====

**Sans librairie à installer** ++++ Voir le code |
<code c>
/* 
 * USE TWO AD9850
 * Modified from http://nr8o.dhlpilotcentral.com/?p=83
 */
 
 // 1st MODULE
 #define W_CLK 8       // Pin 8 - connect to AD9850 module word load clock pin (CLK)
 #define FQ_UD 9       // Pin 9 - connect to freq update pin (FQ)
 #define DATA 10       // Pin 10 - connect to serial data load pin (DATA)
 #define RESET 11      // Pin 11 - connect to reset pin (RST).
 
 // 2nd MODULE
 #define W_CLK2 4       // Pin 4 - connect to AD9850 module word load clock pin (CLK)
 #define FQ_UD2 5       // Pin 5 - connect to freq update pin (FQ)
 #define DATA2 6       // Pin 6 - connect to serial data load pin (DATA)
 #define RESET2 7      // Pin 7 - connect to reset pin (RST).
 
 #define pulseHigh(pin) {digitalWrite(pin, HIGH); digitalWrite(pin, LOW); }
 
 // transfers a byte, a bit at a time, LSB first to the 9850 via serial DATA line
void tfr_byte(byte data, int pin_clock, int pin_data)
{
  for (int i=0; i<8; i++, data>>=1) {
    digitalWrite(pin_data, data & 0x01);
    pulseHigh(pin_clock);   //after each bit sent, CLK is pulsed high
  }
}

 // frequency calc from datasheet page 8 = <sys clock> * <frequency tuning word>/2^32
void sendFrequency(double frequency, int pin_clock, int pin_fq, int pin_data) {
  int32_t freq = frequency * 4294967295/125000000;  // note 125 MHz clock on 9850
  for (int b=0; b<4; b++, freq>>=8) {
    tfr_byte(freq & 0xFF, pin_clock, pin_data);
  }
  tfr_byte(0x000, pin_clock, pin_data);   // Final control byte, all 0 for 9850 chip
  pulseHigh(pin_fq);  // Done!  Should see output
}

void setup() {
 // configure arduino data pins for output
  pinMode(FQ_UD, OUTPUT);
  pinMode(W_CLK, OUTPUT);
  pinMode(DATA, OUTPUT);
  pinMode(RESET, OUTPUT);
  
  pinMode(FQ_UD2, OUTPUT);
  pinMode(W_CLK2, OUTPUT);
  pinMode(DATA2, OUTPUT);
  pinMode(RESET2, OUTPUT);
   
  pulseHigh(RESET);
  pulseHigh(W_CLK);
  pulseHigh(FQ_UD);  // this pulse enables serial mode - Datasheet page 12 figure 10
  
  pulseHigh(RESET2);
  pulseHigh(W_CLK2);
  pulseHigh(FQ_UD2);  // this pulse enables serial mode - Datasheet page 12 figure 10
}

void loop() {
  sendFrequency(1320, W_CLK, FQ_UD, DATA);  // freq
  sendFrequency(440, W_CLK2, FQ_UD2, DATA2);  // freq

  while(1);
}
</code>
++++

**Avec la librairie [[http://arduino.alhin.de/download.php?id=28|AH_AD9850.h]]**
++++ Voir le code |
<code c>
// from http://www.arduino-projekte.de 

#include <AH_AD9850.h>

#define CLK     6
#define FQUP    7
#define BitData 8
#define RESET   9

AH_AD9850 AD9850(CLK, FQUP, BitData, RESET);

void setup()
{
  AD9850.reset();                   //reset module
  delay(1000);
  AD9850.powerDown();               //set signal output to LOW
  
  // initialize serial communication
  Serial.begin(9600);
}

void loop(){

 //set_frequency(boolean PowerDown, byte Phase, double Freq); 
 AD9850.set_frequency(0,0,1000);    //set power=UP, phase=0, 1kHz frequency
 delay(1000); 

 AD9850.set_frequency(2500);        //set 2.5kHz frequency
 delay(1000); 
 
 AD9850 << 5000;                    //set 5kHz frequency in C++ style
 delay(1000);
 
 
 //phase test
 for (int phase=0;phase<32;phase++)   
 {
   AD9850.set_frequency(0, phase, 1000);   //change phase delay in 11.25°(2PI/32) steps
   delay(1000);
 }
 
}
</code>
++++


===== Modulation =====
Deux signaux modulés par une porte ET : \\
{{:materiel:ad9850:ad9850-modulation.jpg?400|}}


Le schéma de la porte ET avec deux diodes et une résistance (merci Patrick!)\\
{{:materiel:ad9850:and_10.gif|}}

===== Signal carré =====
Il faut modifier le "duty cycle" du signal carré avec le potentiomètre.

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