HIGH-ACCURACY, SIMULTANEOUS CALIBRATION OF SIGNAL MEASURING SYSTEMS

The authors describe a new calibration method that makes possible a very accurate calibration of a signal measuring system. in this method, they inject a precisely known calibration signal into the measuring system while they acquire the data signal. The calibration signal is designed to have a discrete frequency spectrum that interweaves with, but does not contaminate, the spectrum of the data signal. Since the calibration is performed simultaneously with data acquisition, there is no danger that the equipment response will change between the time when the data are collected and when the instrument is recalibrated. Further, this procedure may be automated so experiments are much more efficient than with separate and frequent calibrations. This calibration technique should be applicable in a wide variety of scientific and engineering problems. To illustrate the power of this technique, the authors use an example from the field of exploration geophysics.