Amplifying DC offset signals

Discussion in 'Homework Help' started by learninmath, Sep 15, 2010.

  1. learninmath

    Thread Starter New Member

    May 19, 2008

    i understand that signals containing DC offset are very small and are often removed before amplifying, but what happens to those signals when they are amplified? I remember my lecturer saying something about them rapidly increasing in frequency and resulting in distortion.

    I may need a good explanation, just to help me understand better.

    thank you in advance.
  2. t_n_k

    AAC Fanatic!

    Mar 6, 2009
    I'm guessing your question is about the issue of amplifying the desired small signal (say from a transducer) having an undesirable (but unavoidable) DC offset.

    A common approach would be to use a true differential amplifier with a high common mode rejection value. The DC is a common mode component and is strongly attenuated while the differential (small) signal is amplified. As long as the DC is within the common mode range of the amplifier the method works reasonably well.

    Another approach is to use an AC only amplifier - basically the DC is blocked by a capacitor in series with the signal prior to amplification.

    Other methods might include pre-nulling or counteracting the DC offset prior to amplification.

    I'm not sure about the meaning of your statement ...