In a direct conversion receiver with zero-frequency intermediate frequency (IF) signal, the DC offset and 1/f noise of the IF signal is compensated by means of double-sampling. The first period of the doubling-sampling is a calibration phase, which stores the DC offset and the 1/f noise. The second period...http://www.google.com/patents/US7194243?utm_source=gb-gplus-sharePatent US7194243 - DC offset and 1/f noise compensation of a direct conversion receiver
