  In this paper, we consider the problem of detecting a multichannel signal in
interference and noise when signal mismatch happens. We first propose two
selective detectors, since their strong selectivity is preferred in some
situations. However, these two detectors would not be suitable candidates if a
robust detector is needed. To overcome this shortcoming, we then devise a
tunable detector, which is parametrized by a non-negative scaling factor,
referred to as the tunable parameter. By adjusting the tunable parameter, the
proposed detector can smoothly change its capability in rejecting or robustly
detecting a mismatch signal. Moreover, one selective detector and the tunable
detector with an appropriate tunable parameter can provide nearly the same
detection performance as existing detectors in the absence of signal mismatch.
We obtain analytical expressions for the probabilities of detection (PDs) and
probabilities of false alarm (PFAs) of the three proposed detectors, which are
verified by Monte Carlo simulations.
