Gabor Dual Frames with Characteristic Function Window Mohammad Ali Hasankhani Fard Sahand Communications in Mathematical Analysis Print ISSN: 2322-5807 Online ISSN: 2423-3900 Volume: 18 Number: 1 Pages: 47-57 Sahand Commun. Math. Anal. DOI: 10.22130/scma.2020.121704.751 -