Hi,

To make the board be "found" by the PC, go into UG-639, the user guide of the evaluation board. You can download this guide from here: 

https://www.analog.com/en/design-center/evaluation-hardware-and-software/evaluation-boards-kits/EVAL-AD9548.html#eb-documentation

Please go to page 6 and follow the instructions at bullet 6:

This will allow the PC to recognize the board, which will make the USB Programmer to identify the board. Use the instructions on the page 6 of UG-639  to program the USB EEPROM.

Petre

Hi, Yes I have read this, and tried it, but the only thing you can do from the Windows Device Manager is to update the driver. But were is the driver? 

HI,

 I remember doing this procedure some time ago and it worked very well. I had the USB programmer recognizing the board like in Figure 3 in UG-639, Cyusb-1.

Are you sure the old AD9548 evaluation board is still functional?

Maybe you should order a new board or try the install procedure on a different pc.

Please also note that if you want to control 1PPS  GPS clock, we now recommend the AD9545 instead of the AD9548. For other control tasks, better use the AD9542. Please take a look at the AD9545 family of devices: AD9545/44/43/42.

Petre

Ok, thank you. Probably the board is broken. I can see the LED CR2 is red (steady) and also the two green LEDs CR3 and CR5 is on. 
I will check the AD9545.

/Per

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

Ok, thank you.

Per

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?

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

Ok, thank you.

Hi Petre,

Is it possible for you to make a configuration file so that I can start the development?  Attached is a link to a brief description of my project. 

https://www.dropbox.com/s/6mql04m1uwzo1yo/TDS%20project%20description.pdf?dl=0

Regards,
Per

Hi,

I have also a couple of hardware questions. I think that the Evaluation Board User Guide and the Evaluation Board doesn't match.

In the manual it says that the Ref input BB  has a built in voltage divider. Is that really the case? If I look at the schematic diagram it is unclear. I just want to be sure so that I don't damage the pcb.

Regarding the System Clock Inputs it is mentioned 49.152 or 50 MHz crystal. If I look at the board and the schematic diagram there is a 52MHz crystal.

Hi,

I have just read the section about System Clock Stability Compensation in the AD9545 manual. If I understand that part correct I can use, for the second AD9545, a 50 or 52 MHz crystal as System Clock Source and another stable source as reference. In my case I will use the 10 MHz from the rubidium oscillator as a reference.

I am not sure what is the best choice for the first AD9545, where the GNSS receiver is connected, 
Maybe the PPS derived from10MHz Rubidium Osc. (Via AD9545 no. 2) or the GNSS PPS can stability compensate the System Clock? Or is better to use a TCXO or OCXO?  In failure mode both PPS from GNSS and Rubidium can be lost so it might be better to have a good 50 MHz TCXO. If so shall I have the 50 MHz oscillator as a third reference and use a 50 or 52 MHz crystal as System Clock or shall I use the TCXO as System Clock?

Regards,
Per

HI,

let's take this conversation offline. I'll contact you directly through email

Petre

Ok, thank you.