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( TSW1200EVM + ADS41B49 ) * 2

Jeffrey Lawrence
Prodigy 10 points
Other Parts Discussed in Thread: ADS4149, ADS4249

Hi,

  I share Chang's frustration with the TI policy of witholding LabView VI's for the TSW1200.  However my problem is somewhat different.

  My research project requires TWO high speed digitizer channels that are externally triggered by Stanford DG535 on a periodic basis.  Upon completion of data capture and USB download, I need to send both data streams to a common location for processing, then automatically re-arm and repeat.

(1) First of all, the TSW1200 GUI refuses to run multiple instances, so I had to setup two computers (one per evm).  These EVMs were purchased very recently and delivered with old software that did not include the external trigger checkbox.  Furthermore, I had to go looking for the ADC file update.

(2) Arming for simultaneous capture from BOTH EVMs is a bit tricky and the EVM has reported timeout errors before the event occurs;

(3) There is no easy way to automatically send captured waveforms from the LabView GUI to an IP address for processing;

(4) I am not even sure if the CAPTURE button re-arms after trigger and download;

(5) I need to make sure both EVMs are recording data generated from the same laser pulse;

I have not tried LabView because our licenses belong to different machines that are not available in the laboratory.  What I could really use is a "C" language API for the TSW1200.

Another issue is the ADS41xx/58B18EVM itself.  This board is delivered with the 983 MHz VCXO and 245.76 MHz filter missing.  These peculiar Epson Toycomm parts are not available at my local Radio Shack, nor my national DigiKey or Mouser either.  The instruction manual expects me to input a 250 MHz sine wave that is 1.5 Vpp.  Fortunately, we found an old HP function generator that weighs about 50 pounds, but we are still evaluating a smaller solution using MiniCircuits oscillator and splitter.  Ideally, we would use two LVPECL line drivers from a common oscillator to synchronize both boards, but the clock options in the SLWU067A does not address this.

I sure hope that TI can offer some practical suggestions so I can make this stuff do my job without having to build a bunch of custom hardware or massively modifying the EVMs.

  • 0
    TI__Mastermind 29220 points

    The EVM and capture card are made available for evaluation on an ADC to determine if it meets the performance criteria of the final system requirements where that ADC would be used.

    The ADC EVM doesn’t come with VCXO and filter because they are made to order for each frequency and we don’t know what frequency a customer will want on the EVM.  Please look for a distributor of high quality components for availability of these items to fit your specific criteria.  ( I am told that we buy our Epson/Toyocom filters from Dove Electronics)

    The User Interface software for the TSW1200 is as flexible as we can make it, given its nature as support for device performance evaluation, and we are adding features as applicable along the way.  For more involved usgaes, or for cusotmers who wish to do their own post-proceessing of the captured data, we make available upon request a small suite of Matlab code that can set up the TSW1200 for capture and then make the data available for your own postprocessing.  If this code would help, we could supply it, and then you could save the captured data as you wish or do what you wish with it.  We did not use of the com port of the TSW1200 in such a way that one PC could access two separate TSW1200's and keep their com ports separate.  But the TSW1200 hardware *is* capable of simultaneous capture from two channels of one EVM into one TSW1200, adn the Matlab code does support that.  If you were to use one 2-channel EVM such as that ADS4249 instead of two ADS4149, then you could capture simultaneous code from both channels. 

    Then if you wish to re-arm the EVMs for another capture and loop or repeat, using the Matlab code you could code that up however you wished.

    Regards,

    Richard P.