Viva Questions for Advanced Communication Lab

VIVA QUESTIONS FOR ADVANCED COMMUNICATION LAB 1. State different types of Digital modulation techniques? 2. What is shift keying? 3. What is a binary modulation technique? 4. Define S!? ". Define #S!? $. Define %S!? &. Define '%S! and D%S!? (. Why '%S! is called quadrature shift keying? ). Define *D+? 1,. What are applications of shift keying? 11. Define #D+? 12. State the applications of multiple-ing? 13. State the principle of %? 14. State coherent detection? 1". State non/coherent detection? 1$. Differentiate bet0een D%S! and '%S!? 1&. What is an +/rray data transmission? 1(. What is a standing 0ae? 1). Define reflection and transmission co/efficient? 2,. State different types of losses in transmission lines 21. Define modes? 22. What is the range of micro0aes? 23. What is the adantage of 0aeguides? 24. Define SW? 2". Define solator? 2$. What is the principle of Directional coupler? 2&. State different types of Directional couplers? 2(. What is a !lystron? 2). State the classification of micro0ae tubes? 3,. What are 5/type and +/type tubes? 31. State application of klystron?

32. State the mechanism of oscillation in klystron? 33. 6o0 modulation occurs in refle- klystron? 34. State t0o methods to find SW? 3". Define the principle of slotted line carriage? 3$. Differentiate bet0een normal and e-panded SW? 3&. What type of frequency meter is used in aboratory? 3(. Define directiity7 radiation efficiency7 beam 0idth and band0idth of an antenna? 3). What are the radiation patterns for 6orn antenna7 parabolic antenna? 4,. State the formula to find directiity for an antenna? 41. What are the adantages of using optical fibers? 42. What is the principle of operation of 5#8? 43. State the difference bet0een step/inde- and graded inde- fiber? 44. State the formula to find the numerical perture? 4". What are the different types of losses in 5#8S?

Q1. What is multiplexing?  Ans: Multiplexing is method by which multiple analog message signals or digital data streams are combined into one signal over a shared mediu

Q2. What are diferent types o multiplexing?  Ans: i) Space-division multiplexing (SDM) ii) Freuency-division multiplexing (FDM) iii) !ime-division multiplexing (!DM) iv) "ode-division multiplexing ("DM)

Q3. What is TDM?  Ans: !DM is the process o# dividing up one communication time slot into smaller time slots$ %&' t is the techniue o# separating the signal in time is called !DM$

Q4. What do you mean by DM?  Ans: Freuency division multiplexing is the techniue o# separating the signal in #reuency is re##ered as FDM$

Q!. What is "mplitude shit #eying $"%#& ?  Ans: t is a type o# digital modulation in which' the digital data modulates amplitude o# the carrier$

Q'. What are diferent types o digital modulation?  Ans: i) hase shi#t *eying (S+) ii) Freuency shi#t *eying (FS+) iii) Amplitude shi#t *eying (AS+)

Q(. What is )hase shit *eying $ )%#&?

 Ans: n this techniue' the digital data modulates the phase o# the carrier$

Q+. What is re,uen-y shit *eying $%#& ?  Ans: n this techniue' the digital data modulates the #reuency o# the carrier$

Q. What is /inary )hase shit #eying $/)%#& ?  Ans: n ,S+' binary symbol ./ and 0/ modulate the phase o# the carrier$

Q01. What is bandidth o /)%# signal?  Ans: ,123#b$ where #b2.4!b$

Q00. What do you mean by Diferential )hase %hit #eying $D)%#&?  Ans: DS+ is di##erentially coherent modulation method$ t does not need a coherent carrier at the demodulator$ !he input seuence o# binary bits is modi#ied such that the next bit depends upon the previous bit$ n DS+ the phase o# the carrier changes only on symbol ./' while in ,S+' phase o# the carrier get changes both at ./ and at 0/$ So this is the ma5or di##erence between DS+ and ,S+$

Q02. What is /andidth o D)%#?  Ans: ,12 #b$

Q03. %ho the phase -hange in D)%# at the digital input 01000010. Ans: Draw it by yourself with help of your textbook.ANSW!

Q0!. Why # ip5op is being used in this type i #eying? Ans: "# $ip%$op is use& in this type of keying in or&er to separate the e'en an o&& bits a((or&ing to the &igital inputs.

Q0'. What are the ad6antages o6er other types o *eying? Ans: i) *he +W re,uire& by Q-S# is ust half of the +-S#. ii) *he information transmission rate is higher. iii) /arrier power remains (onstant.

Q0(. What is a 7899 D:;D
Q0+. =o ould you >nd the propagation loss or to diferent *non length and 6oltage o opti-al >ber. Ans: -ropagation loss2 134561%67) log 87481 . Where 6167 are length of two &i9erent opti(al ber an& 87 an& 81 are the 'oltages a(ross it.

Q0. What is the used ormula to >nd out the bending loss or an opti-al >ber? Ans: *here is no any xe& formula to n& so ben&ing loss is the relation between the 'oltages 58) to

the &iameter 5&) of ben&e& opti(al ber.