  The short-time Fourier transform (STFT), or the discrete Gabor transform
(DGT), has been extensively used in signal analysis and processing. Their
properties are characterized by a window function. For signal processing,
designing a special window called tight window is important because it is known
to make DGT-domain processing robust to error. In this paper, we propose a
method of designing tight windows that minimize the sidelobe energy. It is
formulated as a constrained spectral concentration problem, and a Newton's
method on an oblique manifold is derived to efficiently obtain a solution. Our
numerical example showed that the proposed algorithm requires only several
iterations to reach a stationary point.
