The file train.mat (which comes with MATLAB) contains an audio signal. Its "envelope," denoted y(t) in train.mat is approximated below: ylt) 0.5 1.6 -1 Write a function [y, t]timescale(x, Fs, a) to perform a time scaling and compute y(t) = x(at), given an input signal x(t) (in MATLAB, this is a vector of values) that has been sampled at rate Fs. The file train.mat can be loaded from Matlab using load train.mat The file train.mat (which comes with MATLAB) contains an audio signal. Its "envelope," denoted y(t) in train.mat is approximated below: ylt) 0.5 1.6 -1 Write a function [y, t]timescale(x, Fs, a) to perform a time scaling and compute y(t) = x(at), given an input signal x(t) (in MATLAB, this is a vector of values) that has been sampled at rate Fs. The file train.mat can be loaded from Matlab using load train.mat