i$)$ Explain how high bandwidth memory architectures are realised in DSPs $($distinguishing it from the Harvard architecture$).$ ii$)$ What are the main drawbacks of realising the high bandwidth memory architectures? iii$)$ Explain the fast Fourier transform $($FFT$).$ iv$)$ If $=1012,$ derive how the computational complexity of the discrete Fourier transform $($DFT$)$ differs from the FFT$.$