All questions of Digital Logic for Computer Science Engineering (CSE) Exam

None of the options are equal to 1.

MSI (Medium-Scale Integration) Integrated Circuits

MSI integrated circuits are a classification of ICs that have complexities ranging from 30 to 300 equivalent gates on a single chip.

Characteristics of MSI Integrated Circuits:
- MSI ICs are more complex than SSI (Small-Scale Integration) ICs but less complex than LSI (Large-Scale Integration) and VLSI (Very Large-Scale Integration) ICs.
- They typically contain multiple logic gates, flip-flops, and other components on a single chip.
- MSI ICs are used in a variety of applications such as arithmetic units, multiplexers, encoders, and decoders.

Advantages of MSI Integrated Circuits:
- They offer a higher level of integration compared to SSI ICs, which leads to smaller size, lower power consumption, and improved performance.
- MSI ICs are more cost-effective than LSI and VLSI ICs for applications that require moderate complexity.

Applications of MSI Integrated Circuits:
- MSI ICs are commonly used in consumer electronics, industrial automation, telecommunications, and other fields where moderate complexity and cost efficiency are important factors.
- They play a crucial role in the design of various digital systems and devices.

In conclusion, MSI integrated circuits fill the gap between SSI and LSI/VLSI ICs by providing a moderate level of complexity and integration suitable for a wide range of applications.

BCD stands for Binary Coded Decimal. It is a form of representing decimal numbers using a binary code. In BCD, each decimal digit is represented by a 4-bit binary code. Let's break down the answer and explain why it is option 'B' - 4 bits.

Binary Coded Decimal (BCD)

BCD is a way of representing decimal digits using a binary code. In BCD, each decimal digit is represented by a 4-bit binary code. This means that 4 binary bits are required to represent a single BCD digit.

Binary Digits

In binary representation, each digit can take on one of two values, 0 or 1.

Decimal Digits

In decimal representation, each digit can take on one of ten values, from 0 to 9.

BCD Representation

To represent decimal digits using BCD, each decimal digit is divided into its binary equivalent. For example, the decimal digit 0 is represented as 0000 in BCD, 1 as 0001, 2 as 0010, and so on up to 9 as 1001.

Number of Bits for a BCD Digit

Since each decimal digit is represented by a 4-bit binary code in BCD, we can conclude that 4 bits are required to store one BCD digit.

Examples

Let's consider some examples to further illustrate this:

- The BCD representation of the decimal digit 3 is 0011, which requires 4 bits.
- The BCD representation of the decimal digit 7 is 0111, which also requires 4 bits.
- The BCD representation of the decimal digit 9 is 1001, again requiring 4 bits.

Conclusion

In conclusion, 4 bits are required to store one BCD digit. This is because each decimal digit is represented by a 4-bit binary code in BCD. Therefore, the correct answer is option 'B' - 4 bits.

Explanation:

To calculate the number of states or bit patterns in an 8-bit Johnson counter sequence, we need to understand the concept of a Johnson counter and its sequence.

A Johnson counter is a modified version of a ring counter. It is a sequential circuit that cycles through a fixed sequence of states. In an 8-bit Johnson counter, there are 8 flip-flops connected in a ring, forming a circular shift register.

Johnson Counter Sequence:
The sequence of states in a Johnson counter follows a specific pattern. It starts with all bits set to 0 and then cycles through a sequence of 2^n - 1 states, where n is the number of bits in the counter.

In an 8-bit Johnson counter, the sequence will have 2^8 - 1 = 255 states. However, we need to exclude the initial state (all bits set to 0) from the count.

Therefore, the number of states in the Johnson counter sequence is 255 - 1 = 254.

Orbit Patterns:
An orbit pattern is a subset of the Johnson counter sequence that represents a complete cycle or loop. It starts and ends at the same state.

To calculate the number of orbit patterns, we need to find the number of states in each orbit pattern. In an 8-bit Johnson counter, each orbit pattern will have 8 states, as it takes 8 clock cycles for the counter to return to its initial state.

The total number of possible orbit patterns can be calculated by dividing the total number of states in the Johnson counter sequence by the number of states in each orbit pattern.

Total number of states = 254
Number of states in each orbit pattern = 8

Number of orbit patterns = Total number of states / Number of states in each orbit pattern
= 254 / 8
= 31.75

Since the number of orbit patterns cannot be a fraction, we round it down to the nearest whole number.

Therefore, the number of orbit patterns in an 8-bit Johnson counter sequence is 31.

Conclusion:
The correct answer is option A) 240.

X 10^12 metres
b) 2.8968192 x 10^11 metres
c) 2.8968192 x 10^13 metres
d) 2.8968192 x 10^14 metres

Answer: c) 2.8968192 x 10^13 metres

Components of a Frequency Counter

Frequency counters are electronic devices used to measure the frequency of an input signal. They are commonly used in various applications such as telecommunications, electronics, and research. A frequency counter typically consists of several components that work together to accurately measure and display the frequency of a signal.

The components of a frequency counter include:

1. Accurate Timebase:
- An accurate timebase is a crucial component of a frequency counter.
- It provides a stable and precise reference signal for counting the input frequency.
- It is usually generated by a crystal oscillator or a temperature-compensated oscillator.
- The timebase determines the resolution and accuracy of the frequency counter.

2. Decade Divider:
- A decade divider is used to divide the input frequency down to a manageable range.
- It divides the input frequency by powers of ten, allowing the counter to operate within its counting range.
- The divided frequency is then used as the input for the counter/latch.

3. Counter/Latch:
- The counter/latch is the main component responsible for counting the input signal.
- It counts the number of input cycles within a specific time period.
- The counted value is then stored in a latch for display.

4. Display:
- The display is an essential component of a frequency counter.
- It shows the measured frequency to the user.
- The display can be in the form of a digital readout or an analog display.

Explanation:
Among the given options, the component that is not a part of a frequency counter is the "Encoder" (option D). An encoder is not typically found in a frequency counter.

- An encoder is a device used to convert an analog or digital signal into a different format.
- It is commonly used in applications such as encoding data, controlling motor movements, or generating position feedback.
- However, it is not directly involved in the measurement or counting of frequencies in a frequency counter.

Therefore, the correct answer is option D, "Encoder."

D Flip Flop from J-K Flip Flop

D flip flop is a fundamental building block in digital circuits, which is used to store a single bit of data. It has a single input called the data input (D), which controls the state of the flip flop. The output of the flip flop is the state of the stored data. A D flip flop can be realized from a J-K flip flop by connecting the J and K inputs together and feeding the same input to both of them.

Explanation

The J-K flip flop has two inputs, J (set) and K (reset), and two outputs, Q (state) and Q' (complement). It can store one bit of information and has two stable states: SET and RESET. When J=K=0, the flip flop maintains its current state. When J=K=1, the flip flop toggles its state. When J=1 and K=0, the flip flop sets its state to 1. When J=0 and K=1, the flip flop resets its state to 0.

To convert a J-K flip flop into a D flip flop, we need to connect the J and K inputs together and feed the same input to both of them. This means that J=K=D. The truth table for the D flip flop is as follows:

D | Q | Q'
--|---|---
0 | 0 | 1
1 | 1 | 0

To implement this truth table using a J-K flip flop, we can connect the D input to both the J and K inputs of the flip flop. This means that J=K=D. The truth table for the J-K flip flop with J=K=D is as follows:

D | Q | Q'
--|---|---
0 | 0 | 0
1 | 1 | 1

As we can see, the truth table for the J-K flip flop with J=K=D is the same as the truth table for the D flip flop. Therefore, a D flip flop can be implemented using a J-K flip flop by connecting the J and K inputs together and feeding the same input to both of them.

Conversion of Hexadecimal to Octal

To convert a hexadecimal number to an octal number, we need to follow the following steps:

Step 1: Write down the hexadecimal number

The given hexadecimal number is (1E.43)16

Step 2: Convert the fractional part to decimal

The fractional part is .43

.43 × 16 = 6.88

The integer part is 6.

Step 3: Convert the integer part to binary

1E = 0001 1110

Step 4: Group the binary digits into sets of three

000 111 0

Step 5: Convert each set of three binary digits to octal

0 7 0

Step 6: Combine the octal digits

The final answer is (36.206)8

Converting to 2's complement:
To find the 2's complement of a binary number, you first need to find the 1's complement by flipping all the bits. Then, add 1 to the result to get the 2's complement.

1's complement of 0011 0101 1001 1100:
1100 1010 0110 0011

Adding 1 to the 1's complement:
1
1100 1010 0110 0011
+
0000 0000 0000 0001
-------------------
1100 1010 0110 0100
Therefore, the 2's complement of 0011 0101 1001 1100 is 1100 1010 0110 0100. This binary number represents the negative equivalent of the original binary number.