4.2.2. Consider an adaptive delta modulator with an adaptation decision algorithm as follows:
Look at the last four samples (assume all zeroes before time zero). Change according to
the following table:
1111 +2 V
0111 or 1011 or 1101 +1.5 V
0011 or 0101 or 1001 +1.0 V
0001 +0.5 V
1110 −0.5 V
1100 or 1010 or 0110 −1.0 V
1000 or 0100 or 0010 −1.5 V
0000 −2 V
(a) List the output voltages as a function of the input bits if the input sequence is 1000
0111 1011. (Start at 0 V.)
(b) List the output voltages that would result for the same input sequence with a non-adaptive delta modulator with step size fixed at 1.0 V. (Start at 0 V; add 1.0 V when
the input bit is a one and subtract when it is a zero.)