Generating a square waveform on zc706+fmcdaq2

Hi,

I have built the no-OS project and now been trying to generate the square waveform of 20MHz. I have made the changes in the sine_lut table with the square wave values whereras, I end up with the noise output on the oscilloscope. As per this thread https://ez.analog.com/fpga/f/q-a/102247/square-wave-output-using-fmcdaq2/   there are few hardware filters on DAQ2. Can someone please tell me how do I find the specific filters to be disabled to generate the square waveform.

Or, is there any way without modifying the board,I can generate the square waveform.

Any help is highly appreciated.

Thank you & regards,

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  • 0
    •  Analog Employees 
    on Mar 10, 2020 7:44 AM

    Hi,

    fmcdaq2 is design for RF. Because of the cutoff frequency of the analog filters you can't use the fmcdaq2 to send square waves. You wold have to redesign the schematic and that is beyond the scope of this forum.

    What do you intend to use the square wave for?

    Or, is there any way without modifying the board,I can generate the square waveform.

    Yes, use a GPIO from the FPGA.

    Andrei

  • Hi 

    Thank you so much for the reply. Okay.

    I want to generate the square waveform to drive a specific device. Presently, I am using the ZC706+FMCDAQ2. Could you please tell me who can help me with the schematic? To know which filters have to removed and the design while keeping the major project unchanged.

    Or, Is there any similar board to FMC DAQ2 which would generate the square waveform without making any hardware changes? This would allow me to only change the DAQ2 while keeping the project unchanged.

    It would be really helpful if you could tell me asap.

    Thank you & regards

  • 0
    •  Analog Employees 
    on Mar 10, 2020 12:42 PM in reply to prashin
    Could you please tell me who can help me with the schematic?

    Third party contractors.

    Changing the analog filters means redesigning the whole board.

    Is there any similar board to FMC DAQ2

    If we are talking about devices with high sample rates, the chances are that those devices are used in designs made for RF. The outputs of this boars are AC coupled not DC, as you need. Using a board capable of 1GSPS or more, to transmit a 20MHz square wave is a huge waste of resources...
    There are a few precision DAC out there...

    Probably this is not what you want, but take a look at m2k.
    It uses an AD9963 100MSPS ADC - 75MSPS(150 with interpolation) DAC. Or 16 pins(GPIOs) for the pattern generator and logic analyzer(100MSPS).

    https://wiki.analog.com/university/tools/m2k/scopy/siggen

    Andrei

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  • 0
    •  Analog Employees 
    on Mar 10, 2020 12:42 PM in reply to prashin
    Could you please tell me who can help me with the schematic?

    Third party contractors.

    Changing the analog filters means redesigning the whole board.

    Is there any similar board to FMC DAQ2

    If we are talking about devices with high sample rates, the chances are that those devices are used in designs made for RF. The outputs of this boars are AC coupled not DC, as you need. Using a board capable of 1GSPS or more, to transmit a 20MHz square wave is a huge waste of resources...
    There are a few precision DAC out there...

    Probably this is not what you want, but take a look at m2k.
    It uses an AD9963 100MSPS ADC - 75MSPS(150 with interpolation) DAC. Or 16 pins(GPIOs) for the pattern generator and logic analyzer(100MSPS).

    https://wiki.analog.com/university/tools/m2k/scopy/siggen

    Andrei

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