Question

a) Draw the block diagram of a generic closed-loop digital control system. Show clearly all blocks and all signals (continuous and discrete, including disturbances added to the forward path). b) Explain the advantages of digital control over analogue control. c) Explain why the Zero-Order-Hold (ZOH) operation may destabilize the system. (4) 14)

Answer 1

Block dogrom of Basic digital Lea 10 syyll. Digital polles I controll ZOH DAC D(2) (+) sensor ZOH AT Advantages DAC = Digital to Analog conventor ADC = Analog to Digital conventor zona (zero order hold) Compared to Brital Analog Digital have following -> The effect of distortion, noise, and Interference is much less in digital signals → Digital ciruits are more reliable - Digital cirwits are easy to design - Digital circuits are cheaper than analog circuits pulse train Response Zero-Order Hold Mathematically zot as Mixing with by filter with Rectangular Impulse x(+) _ x064) T , HE+) 1 Рен / Moct) impulse impulse Tra Train mixing low Distorts pass filter spectrum following signal of