gr-correctiq

gr-correctiq removes the fixed DC component that produces a spike at the center frequency of direct-conversion SDR receivers. Its continuously adapting corrector follows the mean I and Q values with a lightweight IIR estimator, while an automatic variant learns the offset for a chosen interval and then freezes it so subsequent signal content is not filtered; frequency or receiver-gain changes trigger a fresh learning pass. A manual corrector applies user-supplied I and Q offsets, and a companion SwapIQ block exchanges the components of complex, interleaved-short, or interleaved-byte streams to repair spectral inversion.

Main author

ghostop14

Last modified

2022-07-28

Project

Upstream repository

Example flowgraphs

These GNU Radio World examples contain one or more blocks from gr-correctiq.

• gr-correctiq DC Spike CorrectionA synthetic direct-conversion receiver signal with a controllable DC offset. The blue trace is the raw spectrum, whose offset appears as a spike at 0 Hz; the red trace passes through gr-correctiq's continuously adapting estimator, which removes the spike without offset tuning. Change DC offset amplitude while the graph runs to watch the correction follow it.