DDS (Direct Digital Synthesis) Analog Devices AD9910 Shield for Arduino
This device is designed to ensure seamless integration with Arduino MEGA 2560
It does not require any extra wires or converters to work properly
For maximum performance we recommend Ultra-low noise reference oscillator RCLN1000
All functions of the DDS AD9910 are brought to the contacts from the Arduino MEGA
With this you can fully reveal all the capabilities of the DDS AD9910 Shield
PCB Design Schematics Case and Software made by GRA & AFCH

Opensource Firmware available on our GitHub repository: github.com/afch/DDS-AD9910-Arduino-Shield
DDS AD9910 Firmware compilation and uploading to Arduino Mega Tutorial: youtube.com/watch?v=Zn1xLlvlVXE
Video review of DDS AD9910 Shield on our YouTube channel: youtu.be/_MUsmr0cAD4

Listing includes:

• RF AD DDS Unit [AD9910 Shield Board]
• Display [OLED] (0,94″ or 1,54″) (optional, choose in selector)
• Clock Source (XO, TCXO, EGEN, OCXO) (optional, choose in selector)
• Arduino Control Board [MEGA 2560] (optional, choose in selector)
• Power Supply [DC 7.5V/2A] [US, EU, UK] [AC plug] (optional, choose in selector)
• Operating Instruction

Key features:

• Low harmonics no more than -60dBc. An output RF transformer is used for the correct operation of the current mirror
• Small spurs
• 4 layer board. Signal lines TOP and Bottom, inner layers Ground and Power
• Low Noise LDO Stabilizers
• Separate power supply for all analog and digital lines (1.8V and 3.3V), 5 pcs IC voltage stabilizers are used.
  Additionally, there is an RF Ferrite bead interchange
• High-speed decoupling Level converter and TTL 5V matching

Types of reference oscillators (optional, choose in selectors):

1. XO – Crystal 25.000 MHz 20 ppm internal oscillator with PLL at 1 GHz
2. TCXO – 40.000/50.000MHz MHz 1 ppm internal oscillator with PLL at 1 GHz
3. OCXO – Oven Controlled Crystal Oscillators deliver the ultimate piezo electric performance with stabilities down to less than ±1 ppm
4. EGEN – External Generator up to 1.5 GHz (to connect an external clock source of up to 1.5 GHz, NOT INCLUDED)

• Additionally balancing transformer is used for TCXO/OCXO and EGEN options

Additionally balancing transformer is used for TCXO, EGEN and OCXO options:

• Easy to connect OLED display
• Control buttons for control via the program menu
• The synthesizer is capable to generate sine wave, AM or FM modulated signal
• The software allows you to select and configure the frequency of the clock generator through the user menu
  (without the need to recompile the program)
• Any settings can be stored in non-volatile EEPROM memory (located at Arduino Mega)
• Basic settings are applied and saved automatically
• This shield support overclocking the AD9910 core to 1.5 GHz (heatsink is recommended)
• DDS AD9910 Shield has ability to generate a signal up to 600 MHz with a core overclocking up to 1.5 GHz
  (to suppress harmonics, it is recommended to  overclock the AD9910 for frequencies above 400 MHz)
• Has ability to increase output power by +4 dBm when “DAC Current HI” is activated

Detailed description:

• Easy to connect OLED display
• Control buttons for control via the program menu
• The firmware allows you to select and configure the frequency of the clock generator through the user menu
  (without the need to recompile the program)
• Any settings can be stored in non-volatile EEPROM memory (located at Arduino Mega)
• Basic settings are applied and saved automatically
• Expanded and convenient DDS clock source menu
• Offset parameter allows adjusting the clock frequency if the deviation from the specified value
• This shield support overclocking the AD9910 core to 1.5 GHz (heatsink is recommended)
• DDS AD9910 Shield has ability to generate a signal up to 600 MHz with a core overclocking up to 1.5 GHz
  (to suppress harmonics it is recommended to overclock the AD9910 for frequencies above 400 MHz)
• It is possible to obtain a low frequency at the DDS output from 10 Hz (modification required, see instructions below)
• Has ability to increase output power by +4 dBm when “DAC Current HI” is activated

Functional features:

• Support of OLED display (selectable in options)
• Buttons for navigating and controlling settings through the program menu
• DDS Shield is capable to generate Sine Wave, AM/FM modulated signal and SWEEP
• Firmware allows selecting and configuring frequency of the clock generator through the user menu
  (without the need to recompile and upload the program)
• All settings can be stored in non-volatile EEPROM memory (located in Arduino Mega 2560 Board)
• Basic settings are applied and saved automatically
• Expanded and convenient DDS Clock source menu
• Offset parameter allows adjusting the core clock frequency if the deviation from the specified value is known
• Shield supports overclocking the AD9910 core up to 1.5 GHz (heatsink is recommended in this case)
• DDS AD9910 Shield has the ability to generate signal up to 600 MHz with a core overclocking up to 1.5 GHz
  (to suppress harmonics it is recommended to overclock the AD9910 for frequencies above 400 MHz)
• It is possible to obtain a low frequency at the DDS output from 10 Hz (modification required, see instructions below)
• Activating ‘DAC Current HI’ increases the output power capability by +4 dBm

Electrical performance:

• Ensured low harmonic level with levels not exceeding -60dBc,
  this is due to the use of an output RF transformer for optimal current mirror operation
• Low Noise LDO Stabilizers with separate power supply for all analog and digital lines (1.8V and 3.3V),
  they utilizes 5 IC voltage stabilizers; additionally there is an RF Ferrite bead interchange
• 4 layered PCB with signal lines on Top and Bottom and inner layers Ground and Power
• High-speed decoupling Level converter and TTL 5V matching
• Remote control of the DDS Generator through a USB connection and PC using the terminal serial port

Specifications:

* When overclocking the core to 1.5 GHz
** When the “DAC Current HI” function is activated

Phase Noise:

This parameter is very important and interesting for those who wants to buy DDS.
Since the intrinsic phase noise of DDS is obviously less than that of PLL generators, the final value is highly dependent on the clock source.
Designing our DDS AD9910 Shield for Arduino we strictly adhered to all recommendations from Analog Devices.
This was done In order to achieve the values stated in the datasheet for the AD9910.
Among these are PCB layout in 4 layers, separate power supply of all 4 power lines (3.3 V digital, 3.3 V analog, 1.8 V digital, and 1.8 V analog).

Figure below shows the phase noise level when using the built-in PLL in DDS.
The PLL multiplies the frequency of the on-board 50 MHz TCXO generator by a factor of 20. The output frequency is 100 MHz.

Figure below shows the phase noise level when using an external reference clock frequency of 1 GHz (RCLN1000), with the PLL OFF.
The output frequency of the DDS is 100 MHz.

Let’s compare these two graphs, for example, at a 10 kHz offset from the carrier: with the internal PLL system engaged,
the phase noise level is -129 dBc/Hz, while with the PLL system disengaged and using external clocking, the phase noise is -140 dBc/Hz.
This means that using an external clock signal results in a phase noise that is 11 dBc/Hz better (lower).

For the same output frequency, but at a 1 MHz offset from the carrier, with the internal PLL system engaged,
the phase noise level is -124 dBc/Hz, while with the PLL system disengaged and using external clocking, the phase noise is -152 dBc/Hz.
This means that using external clocking results in phase noise that is 23 dBc/Hz better (lower).

Conclusion:
When using external clock, you can get much lower phase noise than using the built-in PLL.
But do not forget that in order to achieve such results, increased requirements are put forward to the external oscillator.
For maximum performance we recommend our Ultra-low noise reference oscillator 1GHz RCLN1000.

Ultra Low Noise Reference Oscillator for AD9910 Shield:

1GHz Ultra Low Noise Reference Oscillator -130dBc/Hz @ 10kHz RCLN1000 for DDS AD9910 DDS9912 Units

If you need higher power output:

The first and simplest method to increase the power from the nominal 0 dBm to +4 dBm is by activating the “Hi-Current” option in the menu (refer to Operation instruction).

NOTE: enabling this setting leads to increase in harmonic levels of the output signal.

If this level of power is still insufficient, there is a second method – connecting an external RF signal Amplifier, such as the MMIC MRFA89.
It allows obtaining a DDS signal output power of up to +20 dBm.

IMPORTANT: Since the MMIC MRFA89 Amplifier has maximum output power of +20 dBm and gain of 20 dB, the recommended maximum input signal level is 0 dBm.
Therefore, the ‘Hi-Current’ parameter should be deactivated in the AD9910 Shield menu.

NOTE: as most amplifiers generate harmonics, it is advised to connect an LPF Filter to the Amplifier output for harmonic suppression.
For example, one from the LPF 7th Order Elliptical series that we offer.

Amplifier and Filter for AD9910 Shield:

RF Amplifier 8-2000 MHz, GAIN = 20 dB, P = +20 dBm MMIC MRFA89 SOT-89 [GOLD PLATED]

Low-Pass Filter LPF 7th Order Elliptical 1-1000Mhz 3.5, 7, 14, 28, 144, 433MHz etc for RF Amlifier, Receiver, Transmitter, Mixer, Transceiver, Antenna.

OLED Display Menus:

Remote control of DDS Generator through USB connection from PC using the terminal serial port:

List of Serial Port Commands:

Starting with version 1.02, the ability to control via the serial port has been added.

F – Set Frequency in Hz (100000 – 600000000)
P – Set Output Power in dBm (-72 — 0 OR -68 — +4, depending on “DAC current”)
E – Enable Output
D – Disable Output
M – Get Model
V – Get Firmware Version
h – Help
; – Commands Separator

Example:
F100000;P-2
Set Frequency to 100 kHz, and Output Power to -2 dBm.
Any number of commands in any order is allowed.

Serial Port Settings:

Speed – 115200 Bouds
Data Bits – 8
Stop Bits – 1
Parity – No
DTR – OFF

Windows:

An example of setting up a serial port in the Windows console:

mode COM3 baud=115200 DTR=OFF Data=8

Usage example:

echo F100000000 > COM3

Ubuntu 22.04:

An example of setting up a serial port in the Ubuntu:

sudo usermod -aG dialout $USER_NAME$
sudo chmod a+rw /dev/ttyUSB0
sudo stty -F /dev/ttyUSB0 115200 cs8 ixoff -hupcl -echo

Usage example:

echo “F100000000” > /dev/ttyUSB0

example of command prompt with serial commands for AD9910 DDS RF Unit

DDS AD9910 Shield for Arduino Spectrograms:

GRA & AFCH DDS AD9910 Shield VS DDS Board from China Spectrograms Comparison:

GRA & AFCH DDS AD9910 Shield Spectrograms:

AM (Amplitude Modulation) Modulation Freq: 1kHz, Depth: 50%-FM (Frequency Modulation) Frequency: 1 kHz Deviation: 3 kHz

AM (Amplitude Modulation) Carrier: 1 MHz Frequency: 100 kHz Depth: 50%

DDS AD9910 Shield for Arduino Thermal images:

AD9910 Board temperature measured with Flir E8 thermal imager at Core Clock @ 1000 MHz

AD9910 Board temperature measured with Flir E8 thermal imager at Core Clock @ 1440 MHz

DDS AD9910 Shield Board Connection Diagram:

DDS AD9910 Shield RF Signal Generator by GRA & AFCH:

Operating Instruction