Question: Preliminary Analysis Determine analytical expressions for the impulse response, system function (z-transform of the impulse response), and the frequency response of the linear time-invariant system represented by (2-1). Use freqz ( ) to plot the frequency response of the preemphasis system for a = 0.5 , 0.9, and 0.98. Plot all three functions together, and label the frequency ax is appropriately for an 8-kHz sampling rate. How should a be chosen so that the high frequencies will be "boosted"?