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JuliaComputing / xtrx_julia

XTRX LiteX/LitePCIe based design for Julia Computing
BSD 2-Clause "Simplified" License
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Biases observed in loopback interfaces. #118

Closed sjkelly closed 2 years ago

sjkelly commented 2 years ago

With the acquire_iq.jl script, @zsoerenm noticed that there are subtle biases in the data. They are both static and dynamic. This appears in the first baseband loopback as well. This appears to have not been as observed when performing loopback from the XTRX in the carrier. While using loopback from an XTRX in the XYNC, this issue is more pronounced. Example: image

The offset can be more clearly seen when there is no signal (in this case, failure to acquire at 800MHz): image

sjkelly commented 2 years ago

This is closed in https://github.com/JuliaComputing/xtrx_julia/pull/132

There is other spurious noise and calibrations we need to test for as well, but this bias should be eliminated.