Simultaneous gain, drift and offset estimation in measurement systems using coherent sampling

In instrumentation and measurement systems, external noise is often a significant problem. Amplitude modulation is often employed to transform a lowpass system into a narrowband one. In this paper, a technique is proposed to estimate an amplitude-modulated signal using a matrix representation of coherently sampled repetitive measurement sweeps. It is also shown how the technique may be extended using partitioning of the signal matrix to account for both sensor offset and linear time drift. The method is able to simultaneously produce good estimates of the signal amplitude, drift and offset. Results demonstrate that the technique is promising when applied in situations where sensor drift precludes the normal application of synchronous detection.