A digital-to-analog converter uses a reference voltage of 120 V dc and has eight binary digit precision. In one of the sampling instants, the data contained in the binary register = 01010101. If a zero order hold is used to generate the output signal, determine the voltage level of the signal.

Given Information:  

Reference voltage = Vr = 120 Volts

Number of bits = 8

Required Information:  

Analog voltage at 01010101 = V = ?

V = 39.84372 Volts

Explanation:

Binary Register: 0 1 0 1 0 1 0 1

V = Vr*[ 2⁻¹(0) + 2⁻²(1) + 2⁻³(0) + 2⁻⁴(1) + 2⁻⁵(0) + 2⁻⁶(1) + 2⁻⁷(0) + 2⁻⁸(1)]

V = 120*[ 0.5(0) + 0.25(1) + 0.125(0) + 0.0625(1) + 0.03125(0) + 0.015625(1) + 0.007812(0) + 0.003906(1)]

V = 120*[ 0.25 + 0.0625 + 0.015625 + 0.003906]

V = 120*[ 0.332031]

V = 39.84372 Volts

Therefore, the analog voltage corresponding to binary register 01010101 is 39.84372 Volts