“…On the other hand, a mismatched filter is not subject to the constant modulus constraint, so that the corresponding optimisation problem is much simpler. It has indeed been shown in [4] and in [5] that an optimal mismatched filter that minimises the ISL or the PSLR can be calculated through a convex problem. For instance, in [4], the mismatched optimisation problem is reformulated as an equivalent convex quadratically constrained quadratic program (QCQP).…”