DAC3482EVM: Example waveform using TSW1400 is not what was expected

Andrew Dowd1

Part Number: DAC3482EVM
Other Parts Discussed in Thread: DAC3482, CDCE62005,

After some difficulty in getting the registers to load (see previous postings), I finally got everything (DAC3482, CDCE62005 and TSW1400) configured as described in the DAC3482EVM manual (Section 3.4 - DAC348x Example Setup Procedure). This produced an output that looks somewhat related to the correct waveform. However, it seems like something saturating or the data capture is introducing some errors. I tried a number of different registers adjustments to see if I could resolve the problem. Most of my register changed altered the output spectrum (so I am changing things!), but none were correct. The spectrum I'm getting when I use the precise register values specified in the EVM manual is the following:

Of course, from the EVM manual, what I'm expecting to see is:

Any suggestions appreciated.

over 3 years ago

0 Kang Hsia over 3 years ago

TI__Guru 66184 points

Hi Andrew,

If you are using the NCO/complex mixer, please be sure to initialize the NCO/complex mixer after programming. This is typically done with a simple toggle on the SIF_SYNC button.

0 Andrew Dowd1 over 3 years ago in reply to Kang Hsia

Prodigy 160 points

Yes, I toggled the SIF_SYNC button. I tried with the Mixer enabled and disabled. The results were different but still wrong (it was hard to be certain due to the nature of the baseband signal, but It looked about what I would expect, if you mixed the signal). I will post the results with both NCO enabled and disabled.

0 Andrew Dowd1 over 3 years ago in reply to Andrew Dowd1

Prodigy 160 points

Here is the output with the Mixer disabled...

0 Andrew Dowd1 over 3 years ago in reply to Andrew Dowd1

Prodigy 160 points

FYI - As I have to manually configure the CDCE62005, It is possible there is an issue with my clock configuration. Here is a snapshot of this screen after manual configuration. I tried to verify it by comparing the register values to the values in the DAC3482_FDAC_1228p8MHz_4xint_NCO_30MHz_QMCon.txt file.