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Hi,
I see a large LO feedthru (DC offset). How do I control this? Should i be playing with the WarpRadio_v1_DACOffsetAdj(chan,value,radios) settings? Do you recommend appropriate values for this?
Thanks,
Raghu
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The radio board needs to be calibrated. This is something we now do to boards before they're shipped, but yours probably still need it.
We have an easy way to automatically calibrate the boards. I just posted the details to the WARP documentation - WARP Radio Tx DC Offset Calibration.
I think everything you need is posted there. Let me know if something isn't clear or doesn't work.
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There are 2 switches on the FPGA board. Which DIP switche should be set? SW2 or SW3? SW3 is closer to the 7 seg display. SW2 is closer to card slot 1.
Also, can you post what kind of msgs will show up on TeraTerm? I see only
"Radios 2 and 3 configured and enabled"
"Sweeping sinusoid enabled"
Thanks,
Raghu
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Ok. I used the switches closer to the radio 1, SW2 and I was able to calibrate. I get values -31 and 217 for the IChan and QChan. This is written to the EEPROMS by the calibration bitstream and is read back as -32 and 218, which is perhaps OK. However, when I read the EEPROMs from my program using the function Calibrate_TxDCO(), what I read back is -2 and 0 for the I and Q channels.
The carrier leakage does not seem to improve even when I hardcode the numbers -31 and 217.
Raghu
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I just updated the TX DCO page with some more directions and code fixes. I forgot to include the step of initializing the radio board's EEPROM. We do this before shipping boards now, but yours might still need it. Also, I updated the EEPROM driver to work over a wider range of bus clock frequencies. Be sure to update your EDK_user_repository and clean software in your XPS project to get the new driver.
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I was able to initialize the EEPROM and calibrate the radios. When the calibration process reads the values it writes to the EEPROM, they seem to be OK. But, when I read the values in my program using the function call posted on the calibration page, it always reads I=2 and Q=0. It also seems to change the center freq for some reason.
Anyway, I am making progress with my design on other fronts. This is not so critical for me at this point.
Thanks,
Raghu
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