The concept of using different weighting functions for the determination of transient time constants was discussed in the original paper on DLTS by Lang [1]. Although the lock-in and box-car techniques provide very good sensitivity, the time constant resolution has always been a problem. More elaborated analysis using approaches that optimise the weighting function showed that in this way it is not possible to distinguish time constants in the transient which differ by a factor less than 6 [2]. The paragraphs on the Laplace DLTS or conventional DLTS measurements describe the major differences between the standard DLTS and the approach offered by this system.
References
[1] D.V. Lang, J. Appl. Phys. 45, 3023 (1974).
[2] A. A. Istratov O. F. Vyvenko, H. Hieslmair, and E. R. Weber, Meas. Sci. Technol., 477, 9, 1998.