In the design of digital FIR filters, when we choose a causal window with a specified magnitude characteristic, the window function that minimizes the mainlobe width typically has which of the following features?

An 8-point Discrete Fourier Transform (DFT) of a real-valued sequence yields: X[0] = 4, X[1] = 2 + j3, X[2] = 1 + j, and X[3] = 0 + j2. What is the value of X[6]?

During the process of Interpolation, Upsampling is followed by _______.

Consider a continuous-time system represented by the differential equation: dy(t)dt + 0.1y(t) = x(t) A digital filter is obtained using the first forward difference method where the derivative part is replaced with (y[n + 1] - y[n])/T. The values of sampling period T, for which the resulting digital filter is stable, are given by: