A circuit shown below, is called a multiplying DAC by feeding an analog signal to the Vet terminal. For an input 0.2sinot volts, together with an additional op-amp to obtain Vo=20Dsinot, where D is the digital word and N=4. a) How many discrete sine-wave amplitudes are available at the output? b) What are the smallest and the largest value of analog signal? c) To what digital input does a 5V peak-to-peak output correspond? V www R/2 50R ww Rf + Vref R 2R 4R < 8R R/2 ww Rf + A Vo.