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AD9548 USB driver problem.

Hi, I have an old AD9548 evalution board which I try to connect via USB to my Windows 10 computer and I can't get it to work. In the Windows device manager it is shown as unknown. I have also tried to update the board using USB Eval Board programmer but the board is not found. What can be the problem?

Regards,

Per

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  • Hi Petre, 
    Can you please guide me to the right choice of IC?
    I have a project where I intend to discipline a Rubidium Oscillator using a PPS from a uBlox GNSS receiver. When starting up the PPS from the receiver will be available as long as needed but in normal mode the PPS is only switched on for shorter periodes during a day. 
    This means that the circuit needs to have good holdover performance and take into account the Rubidium aging etc. The system must also produce a low jitter PPS.

    Is AD9545 the right choice? 

    /Per

  • HI,

    I do believe the AD9545 is the right choice. It can lock onto a 1PPS clock with a DPLL loop bandwidth of 50mHz. The 2.4GHz system clock will be created using a 52 MHz crystal resonator which will make the AD9545 outputs to have the best phase noise performance. You will need to use a OCXO with around 10MHz or 20MHz to stabilize the effect of the system clock wonder (induced by the 52MHz crystal wonder). The OCXO will make the DPLL to permanently lock in phase and frequency onto the 1PPS.

    In holdover, the outputs will be as stable and as precise as the OCXO.

    I do not know how you will account for the Rubidium aging. If you give me more info, maybe we can find a way.

    One more note: some Ublox GNSS receivers have a quantization noise that appears at the 1PPS output as a spur within the 50mHz bandwidth. This means this spur will be seen at the AD9545 output because the DPLL tries follows the 1PPS. Ublox provides a measure of this error and the controller can update the AD9545 to compensate it, but we need to create the 1PPS loop in a different way.

    When you'll have an AD9545 eval board, please give me exact info about what you want the AD9545 to do and I'll create a configuration file for you to start the development.

    Petre

  • Hi Petre,

    Thank you for your support. I will come back to you in this matter. 

    Per

  • Hi Petre,

    Is it possible, via the AD9545, to measure the time difference between two PPS? My idea is to measure the difference between the GPS PPS and a PPS created by the Rubidium Oscillator. This value will then be used by our MCU to correct the frequency of the Rubidium oscillator.

    Per 

  • HI,

    Yes, the AD9545 can do this. See section Timing skew measurements using two TDCs, page 130 in the rev C data sheet.

    Petre

  • Hi,

    I have now received the AD 9545 development board but the ACE software crashes. I have not downloaded the new versions as there is a warning in the AD 9545 Evaluation Board User Guide not to do that. What can be the problem?

    Regards,
    Per

  • I solved the problem but now there is another issue.

    Why is it unapproved?

  • Hi,

    please do not worry about this unapproved status. This is why we have to recommend using a certain version of ACE that can work with it.

    Whenever you launch the 1.10.2671.1118 ACE version, click Close on the window asking you to update ACE.

    Petre