AD9129 Evaluation Board & Xilinx ML-605 Reference Design Questions

Discussion created by Dhersam on Feb 12, 2016
Latest reply on Feb 23, 2016 by Dhersam
Branched from an earlier discussion

Hello Analog Devices

            I’m a physics undergraduate at California Polytechnic and am currently working on the AD9129 Evaluation Board to Xilinx project (https://wiki.analog.com/resources/fpga/xilinx/interposer/ad9129). We have all the listed components for the procedure along with a voltage controlled oscillator (Mini-circuits ZX95-2405C-S+, http://www.minicircuits.com/pdfs/ZX95-2405C+.pdf) running the DAC as a clock source. This particular oscillator produces a measured output of 2.1 GHz at a power of -1.3dBm. Although this varies slightly from the project description, it should still be an adequate source according to the data sheet for the DAC (http://www.analog.com/media/en/technical-documentation/data-sheets/AD9119_9129.pdf).

As I understand it, the firmware for the FPGA should produce a digital sine wave with a frequency of 300 MHz, and the AD9129 SPI LabView VI is driving the DAC. When I run the AD9129 SPI program and after programming the FPGA as in the instructions, I observe multiple peaks in the spectrum of the RF output from the DAC space by 65 MHz as shown in the screen shot below. I would expect to see a single peak at 300 MHz.

So far in the testing I've programmed the BIT file through impact and have used the TeraTerm program to connect to the FPGA, setting the baud rate to 57600. Following this process a prompt appears in the terminal which matches what appears on the project page.

The issue I'm having is that the SPI program seems to not have the exact same results as is described. After DLL is disabled and enabled, we receive a broadband noise spectrum with no real distinct peaks besides a small peak about 5 or 10 dB above the noise level. Its frequency changes over time when the PD ALL button is toggled, but settles on a frequency near 355 MHz after a few seconds. After toggling the PD ALL button a few times, I noticed that the settling frequency ranges between ~340 to 360 MHz.

Also, the DLL warning indicator light is switched on. I do not understand the controls on the AD9129 SPI VI, and am at a loss to debug this. Any information or documentation on the “AD9129 SPI” program will be extremely helpful.

I am brand new to using both the Xlinix ML605 and AD9129, so I would appreciate any advice you could give me.