Electronics > FPGA

For anyone complaining about 8 bit FFTs... (Xilinx GTX as 1-bit "SDR")

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daveshah:
As a random curiosity I decided to see if I could use the GTX transceiver in a Xilinx Kintex-7 FPGA as a very fast (theoretically 10GSPS, my current setup limits me to 6.75GSPS) 1-bit ADC.

I fed the output of an LNA into one of the transceiver pins (a balun would have been better, but I didn't have one and didn't fancy trying to build a wideband microwave one), captured a total of 1M samples using Vivado ILA, and ran an FFT on them in Python. I was using a single MAAL-010704 which is not nearly enough gain at higher frequencies but I was having oscillation issues so couldn't cascade two as I was hoping to.

Attached is the spectrum I see with a WiFi device transmitting nearby - it's not brilliant but it's a proof of concept at least...

KE5FX:
Nice proof of concept!  I hope you're reading that data into a buffer that's at least 128 megasamples in length, or the usual suspects will be along to dismiss your efforts as obsolete and useless.  :-DD

antti:
FPGAs are so much fun, and the GTx can be used for many special functions to make many things their are not made for ;)

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