Attached are some spectra of the CLF/LO error and control signals.

For the CLF the error signal is limited by slew rate problems below 500 Hz, and the control signal and the RF6_I channel are limited by slew rate and digitization noise below 50 Hz, respectively. The black curve was measured with 16 dB more fast gain, indicating that the ugf is around 1 kHz at the nominal gain setting.

The LO signals suffer from a similar misery. The error signal is mostly worthless. The control signal and the OMC_TRANS_RF3_I look reasonable down to ~20 Hz and ~70 Hz, respectively.

We should apply the same fix as we did for the IMC/REFL_SERVO boards.