US Patent 7541852 Self-correcting buffer

In general, in one aspect, the disclosure describes an apparatus having a capacitor to receive an input signal and to block DC portion of the incoming signal. A buffer is used to receive the DC blocked incoming signal and output an outgoing signal. A low pass filter is used to convert duty cycle error in an outgoing signal to a DC offset and to provide the DC offset to the capacitor. The DC offset is used to bias the capacitor. The biasing of the capacitor can adjust the DC blocked incoming signal so as to reduce the duty cycle error in the outgoing signal.