的离散时间傅里叶变换cos(nπ6)(n+3)πcos(nπ6)(n+3)π
我想把它变成一个 sinc,但在底部有,如果我替换,那么我不知道如何在新的n+3n+3n+3n+3−π/2−π/2cos((π/6)m−0.5π)cos((π/6)m−0.5π)
有人可以通过我提示吗?
暗示:
cos(nπ/6)(n+3)π=cos[(n+3)π/6−π/2](n+3)π=sin[(n+3)π/6](n+3)πcos(nπ/6)(n+3)π=cos[(n+3)π/6−π/2](n+3)π=sin[(n+3)π/6](n+3)π