A practical technique is described for high sensitivity recording of input signals having a large dynamic range. The circuit senses when the input signal exceeds preset limits and applies a precise and stable baseline shift in the correct sense to maintain the output within these limits. The circuit may be regarded as a black box to be inserted between an analog signal source and a recording device and requiring no alteration to either. A system is presented in detail which permits recording of signals within the range −5.4 to +6.1 V on a recorder at 1.0 V full scale sensitivity. The drift introduced by this system is maintained at less than 1 mV/°C over a wide ambient temperature range. A discussion of the sources of error is presented and techniques for reducing these errors are described.