Bangladsh Bank-Assistant Maintenance Engineer-2013
Q-1.Implement
OR gate using only NAND gates showing logic expression at the output terminals
of each NAND gates.Use A and B as input Boolean variables.
The NAND and NOR gates are the complements of the previous AND and OR functions respectively and are individually a complete set of logic as they can be used to implement any other Boolean function or gate. But as we can construct other logic switching functions using just these gates on their own, they are both called a minimal set of gates. Thus the NAND and the NOR gates are commonly referred to as Universal Logic Gates.
Q-2.Draw a
ripple decade counter circuit diagram using J-K flip-flops.
Ans:
A binary coded decimal
(BCD)/ripple decade counter is a serial digital counter that counts ten digits
.And it resets for every new clock input. As it can go through 10 unique
combinations of output, it is also called as “Decade counter”. A BCD counter
can count 0000, 0001, 0010, 1000, 1001, 1010, 1011, 1110, 1111, 0000, and 0001
and so on.
The above figure shows a decade counter constructed with JK flip flop. The J output and K outputs are connected to logic 1. The clock input of every flip flop is connected to the output of next flip flop, except the last one.
The output of the NAND
gate is connected in parallel to the clear input ‘CLR’ to all the flip flops.
This ripple counter can count up to 16 i.e. 24.
Decade Counter Operation
When the Decade
counter is at REST, the count is equal to 0000. This is first stage of the
counter cycle. When we connect a clock signal input to the counter circuit,
then the circuit will count the binary sequence. The first clock pulse can make
the circuit to count up to 9 (1001). The next clock pulse advances to count 10
(1010).
Then the ports X1 and
X3 will be high. As we know that for high inputs, the NAND gate output will be
low. The NAND gate output is connected to clear input, so it resets all the
flip flop stages in decade counter. This means the pulse after count 9 will
again start the count from count 0.
Truth Table of
Decade Counter
Q-3.Five channels , each with a 100 KHz bandwidth , are to be multiplexed together.what is the minimum bandwidth of the link if there is a need for a guard band of 10 KHz between the channels to prevent interference ?
Q-4.Write
in order the names of layers of OSI model in Computer networking
Q-5.Write
the results of the execution of the following 8086 assembly codes.
(Incomplete Question)
Q-6.What
are five major activities of an operating system regarding process management ?
Ans: A process is an active program i.e a program that is under execution. It contains the program code, program counter, process stack, registers etc. Process Management deals with processes and the various mechanisms to handle them.
The various activities that the
operating system performs with regard to process management are mainly process
scheduling and context switching.
Five
major process management activities of an operating system are :
a. creation and deletion of user and
system processes.
b. suspension and resumption of
processes.
c. provision of mechanisms for
process synchronization.
d. provision of mechanisms for
process communication.
e. provision of mechanisms for
deadlock handling
Q-7.Calculate
the number of trunks that can be supported on a time multiplexed space switch
given that, 32 channels are multiplexed in each stream, while the control
memory access time is 100 ns and the bus switching and transferring time is 100 ns per transfer
Q-8.Write
stands for: OMR, OCR, MICR, ATM
Ans: OMR: Optical Mark reading (OMR) is a method of entering data into a computer system. Optical Mark Readers reads pencil or pen marks made in pre-defined positions on paper forms as responses to questions or tick list prompts. The OMR data entry system contains the information to convert the presence or absence of marks into a computer data file.
OCR: Optical character recognition or optical character reader (OCR) is the electronic or mechanical conversion of images of typed, handwritten or printed text into machine-encoded text
MICR: Magnetic ink character recognition code, known in short as MICR code, is a character recognition technology used mainly by the banking industry to streamline the processing and clearance of cheques and other documents.
ATM: An automated teller machine (ATM) is an electronic banking outlet that allows customers to complete basic transactions without the aid of a branch representative or teller.
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