WL-FlexDDS-NG

Flexible Multi-Channel Phase-Continuous 1 GS/s 400 MHz Agile Radio Frequency Source

  Manual

FlexDDS-NG is a multi-channel phase continuous direct digital signal synthesizer (DDS). Based on the successful design of the FlexDDS multi-channel Radio Frequency source developed for the Max Planck Institute for Quantum Optics, FlexDDS-NG is the next generation waveform generator which directly addresses the needs of experimental physicists.

The FlexDDS-NG mainframe integrates a powerful dual-core 900 MHz ARM computer with 1 GByte of RAM running embedded Linux. More than 500 MBytes of instructions for the waveform generator slots can be stored inside the rack acting like a vast FIFO storage. For more demaning applications or to free up the load from lab control computers, you can run your own programs on the FlexDDS-NG's integrated computer. In contrast to the legacy FlexDDS, the FlexDDS-NG features a high speed GBit Ethernet interface (instead of USB) which eliminates all operating system driver issues. It also allows to control the FlexDDS-NG from any computer — and even to control multiple channels from different computers.

Up to 6 independent but fully synchronized Radio Frequency generator slots can be inserted into the FlexDDS-NG mainframe. This enables up to 12 RF output channels when fully equipped with FlexDDS-NG-1GS RF generator slots. From a network perspective, each slot corresponds to its own network port, so they can be controlled both independently or simultaneously. Each slot has its own digital trigger and synchronization I/Os. In addition, the mainframe provides global trigger inputs allowing to synchronize multiple slots.

Features

  • Multi-channel Direct Digital Synthesis (DDS) platform:
    Up to 12 independent but synchronized output channels when equipped with 6 FlexDDS-NG-1GS generator slots
  • Fast real-time control of all signal parameters
    Execution of complex sequences with deterministic timing
  • Versatile signal generation: See slot description below
  • Excellent signal quality (low phase noise, spurs, harmonics)
  • Integrated computer with dual-core 900 MHz ARM processor running Linux:
    More than 500 MB of command storage in the rack
    Endless possibilities: You can run your own programs on it
  • GBit Ethernet interface:
    High speed real-time command streaming over the network
    Removes length restriction of USB cables and the need for operating system drivers
  • External 10 MHz reference clock input and output.

❝Thank you very much! The DDS made a number of really cool experiments possible.❞

Prof. David S. Hall, Department of Physics and Astronomy, Amherst College

Downloads

FlexDDS-NG Manual
Date: 2021/8/2
Size: 2677 KB
Firmware and Drivers
Date: 2021/6/16
Size: 8495 KB
Firmware Update Instructions
Date: 2021/2/22
Size: 416 KB
LabView Drivers
Date: 2021/2/22
Size: 195 KB

News

   June 16, 2021
A new firmware has been released. This is a big update for the Linux OS and it fixes occasional slot detection failures. Updating is recommended for everyone. (Rack version: 0.61, slot version: 0.62e)
   July 3, 2020
New firmware has been released. It implements the per-channel "dds reset" command known from the USB interface also for the network interface. (Rack version: 0.58, slot version: 0.62)
   September 1, 2019
New firmware release adds config registers in order to route BNC inputs directly to the pins of the AD9910. This enables for instance the use of the OSK feature (fast on/off) or quick switching of profiles.
   August 15, 2019
Wieserlabs would like to thank Andrew Rotunno from the College William and Mary who has put his MATLAB drivers for the FlexDDS-NG on Github: github.com/drewrotunno/FlexDDS.

Components

  • FlexDDS-NG-Rack: Mainframe rack which integrates the GBit Ethernet computer interface and power supply. The rack can hold up to 6 independent Radio Frequency generator slots.
  • FlexDDS-NG-1GS: Dual-channel 1 GS/s 400 MHz Radio Frequency generator slot.

Main Applications

  • Driving AOMs (acousto-optic modulators)
  • Ultra-cold atom experiments; coherent atom manipulation
  • Control loops that require analog modulation
  • BEC evaporation ramps
  • Replacement for VFG-150

Features of Each FlexDDS-NG-1GS Radio Frequency Generator Slot

  • Direct Digital Synthesis (DDS) at 1 GS/s and 14 bit tresolution:
    Precisely repeatable signal generation with a frequency range from 0.3 to 400 MHz(resolution 0.23 Hz)
  • One DDS Command Processor (DCP) per channel with 8 ns timing resolution and separate instruction cache (4096 entries)
    Fast real-time control of all signal parameters
    Execution of complex sequences with deterministic timing
  • Versatile signal generation:
    Phase-continuous linear frequency/amplitude sweeps with external hold and direction inputs, phase ramps, fast profile switching, RAM playback, separate amplitude sweep generator, delay/timing generator
  • Two independent high speed analog modulation inputs: Amplitude, phase, frequency or polar modulation from analog signal sources with up to 20 MHz bandwidth
    Slope and intercept of the transfer function can be digitally set
  • Excellent signal quality (low phase noise, spurs, harmonics) with a Radio Frequency output level up to +10 dBm (2 Vpp) into 50 Ω e.g. to drive mixers directly;
    Phase noise of -100 dBc/Hz at 3 kHz offset from a 200 MHz carrier
  • Fast output on/off functionality, no signal leakage in off state
  • Three real-time digital IOs for external triggering and other functions
  • These slots are also available as a standalone dual-channel generator: See FlexDDS-NG DUAL
FlexDDS-NG-1GS: Dual-channel 1 GS/s Radio Frequency generator slot.

Sample Output Waveforms

Click on each image for more details.

WL-FlexDDS-NG Radio Frequency Generators output waveforms
WL-FlexDDS-NG Radio Frequency Generators output waveforms
FlexDDS-NG-1GS output: Hann shaped chirped pulse using the ramp/sweep generator to change the frequency while the amplitude is fed from the RAM modulation storage.
WL-FlexDDS-NG Radio Frequency Generators output waveforms
WL-FlexDDS-NG Radio Frequency Generators output waveforms
FlexDDS-NG-1GS output: arbitrary pulse shape using the RAM modulation feature with up to 1024 samples. Any amplitude shape can be programmed.
WL-FlexDDS-NG Radio Frequency Generators output waveforms
WL-FlexDDS-NG Radio Frequency Generators output waveforms
FlexDDS-NG-1GS output showing analog modulation:
Top: Externally provided analog modulation signal
Center: Channel 0 configured for analog amplitude modulation
Bottom: Channel 1 set to analog frequency modulation
WL-FlexDDS-NG Radio Frequency Generators output waveforms
WL-FlexDDS-NG Radio Frequency Generators output waveforms
FlexDDS-NG-1GS output: A series of frequecy sweeps; each one can be triggered from a BNC input or internally self-timed.
WL-FlexDDS-NG Radio Frequency Generators output waveforms
WL-FlexDDS-NG Radio Frequency Generators output waveforms
The FlexDDS-NG narrow-band output spectrum shows very little phase noise:
-100 dBc at 300 kHz offset measured in a 10 Hz RBW corresponds to -110 dBc/Hz phase noise at 300 kHz from carrier (at 360 MHz!).
Certain vendors that don't show spectra, perform poorly in this respect.
WL-FlexDDS-NG Radio Frequency Generators output waveforms
WL-FlexDDS-NG Radio Frequency Generators output waveforms
Harmonics at 82 MHz and +10 dBm output power: Harmonics at about -60 dBc for 2nd and 3rd, about -70 dBc for 4th; non-harmonic spurs below -75 dBc (barely visible)