Sequences with low correlation sidelobes have found a wide range of applications in communication systems and RADAR. In this work, we have proposed a computational framework of aperiodic mismatched filtering sequence pairs using iterative twisted approximation (ITROX). A mismatched-filter is a filter where the transmitting sequence and receiving sequence are different (not matched). We have used singular value decomposition (SVD) instead of eigenvalue decomposition (EVD), which is more general, to obtain the resultant sequences. Numerical simulation shows that the resultant aperiodic mismatched filtering sequences have lower sidelobes without reducing too much loss-in-processing gain.