3. Delta Modulation The signal s(t) in figure 3-1 is transmitted through the Delta Modulation scheme shown in figure 3-2. s(t) of figure 3-1 was measured between -5 millisecond and +5 millisecond. The y- axis is in volts. The delta modulation scheme samples the signal s(t) every millisecond to create s(k). Suppose the first sample takes place at t = -5 ms (k=1). The quantizer in figure 3-2 seconds e(k) = +1 to the channel if the input s(k) is higher than the output of the integrator z(k) and e(k) = -1 otherwise. Figure 3-1: the input signal s(L) y-axis -5 -4 3 -2 1 2 3 4 x-axis -3 -4 s(t). Sampler s(k) MODULATOR Quantizer e(k) Integrator z(k) The integrator uses: Design (A): z(k+1) = z(k) + 0.8e(k) CHANNEL DEMODULATOR Integrator Low pass Filter z(k) e(k) Figure 3-2: Design (B): z(k+1) = z(k) + 0.8[e(k)+e(k-1)] 1)=0 z(0) = 4, e(0) = 0 z(0) 4, e(0) = 0, and e(- A. Find the estimate z(k) for design (A) and (B). B. Compare how the two schemes process the signal s(t); discuss advantages and disadvantages of using either scheme for this type of signal; how would you improve the system with respect to signals like s(t)? C. Suppose we doubled the sampling rate (sample every 0.5 milliseconds). Find the estimate z(k) for design (A) and (B). Compare the results to the estimate found in part (A).