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WL-FlexDDS: Flexible Multi-Channel Phase-Coherent 1GSps RF Source

Datasheet
Rev. 2c2_2 (11/2011)
(409 kB PDF)
Programmer's Manual
Rev. 2c_2 (11/2011)
(399 kB PDF)

Description

FlexDDS is a multi-channel phase-coherent RF source. The design deliberately targets the needs of experimental physicists who want to control all signal parameters in real-time from a computer. Initially, a series of actions (like changes in amplitude or frequency, start of frequency sweeps, ...) is compiled into commands which are then transferred to the FlexDDS-Rack via a USB link. Each time a (real-time asynchronious) trigger input is activated, FlexDDS-Rack executes one or several commands and waits for the next trigger event. There is no limit on the number of successive commands as they are loaded continuously from the host computer.

One outstanding feature of FlexDDS is its defined and known phase relationship between channels. For example, two channels can easily be set up to produce an RF output at the same frequency and with equal phase (or specified phase offset). Slightly detuning the frequency of one channel will then linearly increase the phase difference between the two channels.

If you are unsure whether FlexDDS is suitable for your application, feel free to contact us.

Note: This product is not recommended any longer. There is now a next generation multi-channel version called FlexDDS-NG with a flexible Ethernet interface as well as a new dual-channel version called FlexDDS-NG DUAL.

Features:

  • Multi-channel operation with precisely known and adjustable phase relationship between channels
  • Real-time control of all signal parameters
  • Phase-continuous frequency tuning
  • Computer interface (e.g. USB 2.0 link, optional RS-232)
  • New: PDCPU Add-On: Per-Slot processor with 32ns cycle time and 8192 intruction deep memory for added flexibility and fast real-time control of DDS parameters.

Components:

  • FlexDDS-Rack: 19" rack which integrates the computer interface and power supplies.
    The rack can hold up to 8 independent FlexDDS RF generator slots and 1 frontpanel controller slot (FlexDDS-FPCtl).
  • FlexDDS: RF generator slot module
  • FlexDDS-FPCtl: Slot module for reference clock and trigger.

Examples:

FlexDDS output generated with the high speed reconfiguration (PDCPU add-on) and one single DDS profile, no other features in use (no external gating,...). Amplitude and phase specified via "polar mode". First pulse has 180°, second pulse has reduced amplitude and 0°, fourth pulse is the shortest one possible. Time scale: one box is 100 ns.

The narrow-band output spectrum shows very little phase noise. (Some other generators, especially from vendors that don't show spectra, perform badly in this respect.)

FlexDDS output: Hann shaped pulse using the RAM modulation feature with up to 1024 amplitude samples.

FlexDDS output: Hann shaped chirped pulse using the ramp generator to change the frequency while the amplitude is fed from the RAM modulation storage.

FlexDDS output: Arbitrary pulse shape using the RAM modulation feature with up to 1024 amplitude samples. Any amplitude shape can be programmed.

FlexDDS output: A series of frequecy sweeps; each one is triggered from the BNC trigger input. The sweep parameters are streamed from the host computer so any number of such sweeps can be generated in succession.

Full Rack: