Mansoura University 8) Faculty of Engineering ~ ~ . Department of electronics & Comm. Eng. ~ ~ Subject: Electronics Experiments (3) ~~ Instructors: 1- Dr. Mahmoud Elzalabani ~~ 2- Dr. Bedir B. Yousif Date: 22/5/2014 Time allowed: 2 hour Full mark: 50 Final Exam: Two pages· Academic No.: COM9324 Third year communications Solve all the following questions:- ~stion One (15 marks) 1. Explain the basic idea of Wien bridge oscillator circuit operation and drive an expression for the: oscillation frequency? . (4 marks) 2. Calculate the oscillation frequency of a Wien bridge oscillator circuit when R 1 = la kQ, R 2 = 20 kD, and Cl = C 2 = 1 nF. (3 marks) 3. What are the differences between Wien bridge oscillator, Switch-integrator oscillator and multivibrator oscillator? (4 marks) 4. What are the basic steps of troubleshooting a circuit problem? (4 marks) Question Two (18 marks) 1. In RC coupled amplifier circuit experiment : Frequency response ; the size of coupling capacitor affects the frequency response and the bandwidth: Explain this statement with drawing the frequency response curve at C 2 = 1.0 F and (2= O.OlI1F? (4 marks) 2. Define the frequency modulation FM and state the equation of modulated FM signal and its frequency for a single tune input signal? (3 marks) 3. Explain the frequency modulator circuit based on MC1648 VCO illustrated in Fig. I? '-~"--- .• " ..__ • . •• ,..... ..•.. '.. ,' .. n..•. ' ... ",..,,"""="''''_ ..• ".4''<'_.O~'''~''''''''''''''''.='"''''OM'. __ ''''£D''-''=====>ll I (4 marks) c., -sv : . c/' . o'~rf' o : 1 ' .::~II"'~I "!i I II-~~"[ 1;' «: I n ;:,--- t~ _.... -.. L. -\. ... _..- \~ Jr.~.1... r~"L. 3 Q'I~~I F F' I I , •00'- . "----l ~---.,;;_t_-_t _''', .V ;,1'21:1 l :';;lfIF' ~·_~'I'ft.~: i-IQ~ !; ~./ l/;:~[:',!;,,:< I '.- ,:i1:q:'1.l1 " I~ "j I ) •••.•• ' -. .'~- .f c.-.. 'j l_U l.. ·.. ,", '-P. I,'. II "1"':1 -=- "';' I J I \ hi ,.. ,' 'i'.llf I '> :'K 1 <:. .-' :,~~ruf'I:~.~: "-- -1 .. 'C,l .f\ I d' _t. '::': ! ._ ...::.. C'! !SV5,5 4. Explain the operation of phase-locked loop (PLL) circuit and its function? (4 marks) 5. Sketch and explain the block diagram of ·FM to AM conversion discriminator? (3 marks) . Page 1/2

Electronics Lab (3) 2014 - ECED Mansoura · PDF fileDefine the frequency modulation FM and state ... Explain the frequency modulator circuit based on MC1648 VCO ... Sketch and explain

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Page 1: Electronics Lab (3) 2014 - ECED Mansoura · PDF fileDefine the frequency modulation FM and state ... Explain the frequency modulator circuit based on MC1648 VCO ... Sketch and explain

Mansoura University 8)Faculty of Engineering ~ ~ .

Department of electronics & Comm. Eng. ~ ~Subject: Electronics Experiments (3) ~~Instructors: 1- Dr. Mahmoud Elzalabani ~~

2- Dr. Bedir B. Yousif

Date: 22/5/2014Time allowed: 2 hourFull mark: 50Final Exam: Two pages·Academic No.: COM9324Third year communications

Solve all the following questions:-~stion One (15 marks)

1. Explain the basic idea of Wien bridge oscillator circuit operation and drive an expressionfor the: oscillation frequency? . (4 marks)

2. Calculate the oscillation frequency of a Wien bridge oscillator circuit when R1= la kQ,R2= 20 kD, and Cl = C2 = 1 nF. (3 marks)

3. What are the differences between Wien bridge oscillator, Switch-integrator oscillatorand multivibrator oscillator? (4 marks)

4. What are the basic steps of troubleshooting a circuit problem? (4 marks)

Question Two (18 marks)1. In RC coupled amplifier circuit experiment : Frequency response ; the size of

coupling capacitor affects the frequency response and the bandwidth: Explain thisstatement with drawing the frequency response curve at C2= 1.0 F and (2= O.OlI1F?

(4 marks)2. Define the frequency modulation FM and state the equation of modulated FM signal

and its frequency for a single tune input signal? (3 marks)3. Explain the frequency modulator circuit based on MC1648 VCO illustrated in Fig. I?'-~"--- .• " ..__ • . •• ,..... ..•.. ' .. ,' .. n..•. ' ...",..,,"""="''''_ ..•".4''<'_.O~'''~''''''''''''''''.='"''''OM'. __ ''''£D''-''=====>ll I (4 marks)

c., -sv :. c/' .o'~rf'o :

1 '.::~II"'~I"!i III-~~"[ 1;'«:I n ;:,--- t~

_....-.. L. -\. ..._..- \~ Jr.~.1... r~"L. 3 Q'I~~IF F' I I, •00'- . "----l ~---.,;;_t_-_t _''', .V ;,1'21:1

l:';;lfIF' ~·_~'I'ft.~: i-IQ~!; ~./ l/;:~[:',!;,,:< I '.- ,:i1:q:'1.l1

" I~ "j I ) •••.•• '

-..'~- .f c.-.. 'j l_U l..·..,",'-P.I,'. I I "1"':1 -=- "';' I J I \ hi,.. ,' 'i'.llf I '> :'K

1 <:. .-':,~~ruf'I:~.~:"---1.. 'C,l .f\ I

d' _t. '::': ! . _ ...::..

C'!!SV5,5

4. Explain the operation of phase-locked loop (PLL) circuit and its function? (4 marks)5. Sketch and explain the block diagram of ·FM to AM conversion discriminator?

(3 marks)

. Page 1/2

Page 2: Electronics Lab (3) 2014 - ECED Mansoura · PDF fileDefine the frequency modulation FM and state ... Explain the frequency modulator circuit based on MC1648 VCO ... Sketch and explain

Question Three (17 Mark)

USE NEAT SKETCHES TO CLARIFY YOUR ANSWERS:

1) A- For microwave transmission line, define the followingterrns.- -- -

Characteristic impedance - Reflection coefficient-Standing wave ratio (VSWR) - Matched load

B- Sketch the R.M.5 wave form ( standing and travelling) on transmission linefor the following termination load cases:

ZI = 0, ao, Za ,2Z, and 3Zo- and calculate VSWR for each caseC- Sketch the setup of an experiment to measure the frequency ofmicrowave inside waveguide. Explain the steps and the function of eachcomponent.

Page 2/2