DamodarValleyCorp Technical Interview Questions and Answers
1. What is the difference between TDMA and FDMA?
Time division multiple access (TDMA) is a channel access method for shared medium (usually radio) networks. It allows several users to share the same frequency channel by dividing the signal into different time slots. The users transmit in rapid succession, one after the other, each using his own time slot. This allows multiple stations to share the same transmission medium (e.g. radio frequency channel) while using only a part of its channel capacity. TDMA is used in the digital 2G cellular systems such as Global System for Mobile Communications (GSM), IS-136, Personal Digital Cellular (PDC) and iDEN, and in the Digital Enhanced Cordless Telecommunications (DECT) standard for portable phones. It is also used extensively in satellite systems, and combat-net radio systems.
Frequency Division Multiple Access or FDMA is a channel access method used in multiple-access protocols as a channelization protocol. FDMA gives users an individual allocation of one or several frequency bands, allowing them to utilize the allocated radio spectrum without interfering with each other. Multiple Access systems coordinate access between multiple users. The users may also share access via different methods such TDMA, CDMA, or SDMA. These protocols are utilized differently, at different levels of the theoretical OSI model.
2. How many memory locations can be addressed by a microprocessor with 14 address lines?
no of memory locations that can be addressed is 2 to the power of no. of address lines i.e. 2 power 14
3. How do you make a memory card of mobile phone?
A memory chip stores bits and mounted in a card with electrical contacts so a computer or camera can send data to be stored. There is not much more to it than that.
4. What is the difference between Photodiode and Solar cell?
A photodiode is made to detect light quickly a solar cell is made to collect energy from light. They are both typically silicon diodes, but modified to meet their different requirements. A photodiode has to be fast, which means low capacitance, which means small area of silicon. Therefore, it is not very sensitive, and cannot generate much power from light. A solar cell has as large an area as you can afford to buy, getting watts per square inch. There are other differences in the way they are made, and how the PN junction is grown, but they all relate to this difference in purpose.
5.What is D-FF?
6.What is the basic difference between Latches and Flip flops?
7.What is a multiplexer?
8.How can you convert an SR Flip-flop to a JK Flip-flop?
9.How can you convert an JK Flip-flop to a D Flip-flop?
10.What is Race-around problem? How can you rectify it?
11.Which semiconductor device is used as a voltage regulator and why?
12.Explain an ideal voltage source?
13.Explain zener breakdown and avalanche breakdown?
14.What are the different types of filters?
15.What is the need of filtering ideal response of filters and actual response of filters?
16.What is sampling theorem?
17.What is impulse response?
18.Explain the advantages and disadvantages of FIR filters compared to IIR counterparts.
19.What is CMRR?
20.Explain half-duplex and full-duplex communication?
21.Which range of signals is used for terrestrial transmission?
22.Why is there need for modulation?
23.Which type of modulation is used in TV transmission?
24.Why we use vestigial side band (VSB-C3F) transmission for picture?
25.When transmitting digital signals is it necessary to transmit some harmonics in addition to fundamental frequency?
26.For asynchronous transmission, is it necessary to supply some synchronizing pulses additionally or to supply or to supply start and stop bit?
27.BPFSK is more efficient than BFSK in presence of noise. Why?
28.What is meant by pre-emphasis and de-emphasis?
29.Explain 3 dB cutoff frequency? Why is it 3 dB, not 1 dB?
30.Explain ASCII, EBCDIC?
31.How to manufacture the CMOS inverter?
32.What are the advantages of using C band for satellite communication?
33.What frequency bands are used in Satellite Communication?
34.what is the difference between latch and flipflop?what is the main difference between 8085 and 8086 processors?
35.What is the purpose of the package around a microprocessor silicon die?
36.How can we identify how many states the ripple counter is having by looking at the figure as it can also have some invalid states?
37.Design gray to binary code converter?
38.What is a BCD? What are its advantages and disadvantages? Why is an excess-3 code is called an unweighted code?