CS302 GDB Idea Solution Spring July 2012

CS302 GDB Idea Solution Spring July 2012

Solution:

We know that there are circuits in which the output at any instant of time depends not only on the present input of the system but also on the past outputs obtained by the system. Such logic circuits are called sequential logic circuits. We know that sequential logic circuit depends also on the past output of the system. So they require a memory element to store the past outputs. For this purpose the flip-flops are used.

Flip-flops are nothing but the memory elements used in the sequential circuits for storing the past output of the system. A flip-flop circuit can maintain a binary state indefinitely until directed by any input signal to switch states. So proved that memory elementary essential for digital circuits because these memory elements are the backbone of digital circuits and these are required to store the outputs

Advantages One advantage of digital circuits when compared to analog circuits is signals represented digitally can be transmitted without degradation due to noise. For example, a continuous audio signal, transmitted as a sequence of 1s and 0s, can be reconstructed without error provided the noise picked up in transmission is not enough to prevent identification of the 1s and 0s. An hour of music can be stored on a compact disc using about 6 billion binary digits.

In a digital system, a more precise representation of a signal can be obtained by using more binary digits to represent it. While this requires more digital circuits to process the signals, each digit is handled by the same kind of hardware. In an analog system, additional resolution requires fundamental improvements in the linearity and noise characteristics of each step of the signal chain.

Computer-controlled digital systems can be controlled by software, allowing new functions to be added without changing hardware. Often this can be done outside of the factory by updating the product’s software. So, the product’s design errors can be corrected after the product is in a customer’s hands.

Information storage can be easier in digital systems than in analog ones. The noise-immunity of digital systems permits data to be stored and retrieved without degradation. In an analog system, noise from aging and wear degrade the information stored. In a digital system, as long as the total noise is below a certain level, the information can be recovered perfectly