Other Parts Discussed in Thread: ADC12J4000
Hello Jim,
I have a problem with ADC12J4000EVM (Rev. E0) when digitizing analog signal applied to VIN.
Everything works fine when ADC is working in test modes (sending K28.5, RAMP and so on), the data received in the FPGA is perfect.
The problems start when trying to work in the normal mode.
My test conditions are as follows:
- Rf tone freq. applied to VIN is 480MHz
- Vector generator's power is set to -22dBm
The JESD outputs 20 samples at a time and approximately 4 of them look like a sine tone with amplitude +-150 (while full scale range is 2047).
All the other samples look like noise. When I change the signal's frequency to 240MHz, the data in the normally-looking samples reflects the change.
It doesn't seem like the data has nothing to do with the input signal but only 4 out of 20 samples don't look like noise.
What could be the problem?
When I increase input power from -22dBm to -20dBm, the FPGA's GTXs rxbyteisaligned status signals turn to 0.
How can the input signal's amplitude affect rxbyteisaligned signals?
As far as I understand, the default full scale range is 725mVpp into 100 Ohm, which translates to -1.82dBm.
Regards,
Dmitri.