The foreground calibration step is part of the RF-ADC startup initialization state machine sequence. This is managed and carried out by the startup IP. The purpose of the foreground calibration is to provide correction through the OCB1 and OCB2 blocks for sub-RF-ADC offsets and skews of the sampling switches. The OCB2 block is then frozen and not updated again during operation mode. During this process there should ideally be no signal energy at any of the interleaving offset locations, namely frequency = k*Fs/N. Thus the input should be muted during this process. This is typically accomplished by sequencing the receiver front end enable after the RF-ADC startup process is complete. At the end of the foreground calibration process the OCB2 block is frozen, and OCB1, Time Skew and Gain Calibration blocks are set to enable to run in the background.