UNIT I FUNDAMENTALS OF ANALOG COMMUNICATION

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1 CHETTINAD COLLEGE OF ENGINEERING & TECHNOLOGY NH-67, TRICHY MAIN ROAD, PULIYUR, C.F , KARUR DT. DEPARTMENT OF ELECTRONICS AND COMMUNICATION ENGINEERING COURSE MATERIAL Subjet Nae: ANALOG AND DIGITAL COMMUNICATION Subjet Code: CS04 Class / Se: BE (CSE) / III Staff Nae: SUGANYA. J UNIT I FUNDAMENTALS OF ANALOG COMMUNICATION Syllabus Priniples of aplitude odulation, AM envelope, frequeny spetru and bandwidth, odulation index and perent odulation, AM Voltage distribution, AM power distribution, Angle odulation - FM and PM wavefors, phase deviation and odulation index, frequeny deviation and perent odulation, Frequeny analysis of angle odulated waves. Bandwidth requireents for Angle odulated waves. Objetives To study the priniples of aplitude odulation. To define the odulation index and perent odulation. To learn how to draw the frequeny spetru, power spetru and output envelope of an AM DSB FC wave for different values of odulation index. To know how to alulate the bandwidth, power and voltages of the odulated arrier, upper side band and the lower side band of an AM DSB SC wave by solving probles. HISTORY OF COMMUNICATION SYSTEMS 1831 Sauel Morse invents the first repeater and the telegraph is born 1837 Charles Wheatstone patents "eletri telegraph" 1849 England to Frane telegraph able goes into servie -- and fails after 8 days Morse patents "liking" telegraph England-Frane oerial telegraph servie begins. This one uses gutta-perha, and survives.

2 1858 August 18 - First transatlanti telegraph essages sent by the Atlanti Telegraph Co. The able deteriorated quikly, and failed after 3 weeks The first transontinental telegraph line is opleted 1865 The first trans-atlanti able goes in servie 1868 First oerially suessful transatlanti telegraph able opleted between UK and Canada, with land extension to USA. The essage rate is words per inute The trans-atlanti essage rate is inreased to 0 words per inute Baudot invents a pratial Tie Division Multiplexing shee for telegraph. Uses 5-bit odes & 6 tie slots bps ax. rate. Both Western Union and Murray would use this as the basis of ultiplex telegraph systes Typewriter invented Alexander Graha Bell and Elisa Grey independently invent the telephone (although it ay have been invented by Antonio Meui as early as 1857) 1877 Bell attepts to use telephone over the Atlanti telegraph able. The attept fails Oliver Heaviside's analysis shows that a unifor addition of indutane into a able would produe distortion less transission Test alls plaed over five iles of under-water able San Franiso-Oakland gutta-perha able begins telephone servie Alexander Graha Bell inorporated AT&T 1885 Jaes Clerk Maxwell predits the existene of radio waves 1887 Heinrih Hertz verifies the existene of radio waves 1889 Alon Brown Strowger invents the first autoated telephone swith 1895 Guglieo Maroni invents the first radio transitter/reeiver 1901 Guglieo Maroni transits the first radio signal aross the Atlanti 1901 Donald Murray links typewriter to high-speed ultiplex syste, later used by Western Union 1905 The first audio broadast is ade 1910 Chesapeake Bay able is first to use loading oils underwater 1911 The first broadast liense is issued in the US

3 191 Hundreds on the Titani were saved due to wireless 1915 USA transontinental telephone servie begins (NY-San Franiso). 194 The first video signal is broadast 197 First oerial transatlanti radiotelephone servie begins 199 The CRT display tube is invented 1935 Edwin Arstrong invents FM 1939 The blitzkrieg and WW II are ade possible by wireless 1946 The first obile radio syste goes into servie in St. Louis 1948 The transistor is invented BASICS OF COMMUNICATION SYSTEMS Couniation Couniation is defined as the transission of useful inforation fro one point to another through a ouniation hannel. The proesses involved in the ouniation are: Message signal generation Enoding of essage sybols Transission of enoded sybols Deoding and reprodution of original sybols in the reeiver Rereation of original essage signal There are two ajor types of ouniation naely wired ouniation and the wireless ouniation. The wired ouniation is the ouniation done through a physial hannel whih exists between the transitter and the reeiver. Eg.: Twisted pair able, o-axial able, optial fiber able. The wireless ouniation is the ouniation in whih there is no physial ediu between the transitter and the reeiver. Eg.: Mobile ouniation, satellite ouniation, transission by irowaves.

4 Couniation Syste A ouniations subsyste is a funtional unit or operational assebly that is saller than the larger assebly under onsideration. Couniation subsyste basially onsists of a reeiver, frequeny translator and a transitter. It also ontains transponders and other transponders in it and ouniation satellite ouniation syste reeives signals fro the antenna subsyste. Basi Couniation Syste The objetive of designing a ouniation syste is to reprodue the eletrial signal at the reeiving end with inial distortion. The blok diagra of a generi ouniation syste is shown in Figure 1.1. The inforation soure produes sybols (suh as English letters, speeh, video, et.) that are sent through the transission ediu by the transitter. The ouniation ediu introdues noise, and so errors are introdued in the transitted data. At the reeiving end, the reeiver deodes the data and gives it to the end user.

5 COMPONENTS OF A CONTINUOUS WAVE MODULATION (a)transitter (b)reeiver Modulator: Modulation is a proess of transforing the signal so that the signal an be transitted through the ediu. It is a proess by hanging the harateristis of the arrier wave with respet to the instantaneous value of the aplitude of the odulating signal. The harateristi of the arrier wave inludes aplitude, phase and frequeny. The devie used for odulation proess is alled Modulator. Deodulator: The deodulator perfors the inverse operation of the odulator. Modulation and Deodulation Modulation an be defined as superiposition of the signal ontaining the inforation on a highfrequeny arrier. Exaple: If we have to transit voie that ontains frequeny oponents up to 4kHz, we superipose the voie signal on a arrier of, say, 140MHz. The input voie signal is alled the odulating signal. The transforation of superiposition is alled the odulation. The hardware that arries out this transforation is alled the odulator. The output of the odulator is alled the odulated signal. The odulated arrier is sent through the transission ediu, arrying out any other operations required on the odulated signal suh as filtering. At the reeiving end, the odulated signal is passed through a deodulator, whih does the reverse operation of the odulator and gives out the odulating signal, whih ontains the original inforation.

6 The odulating signal is also alled the baseband signal. In a ouniation syste, both ends should have the apability to transit and reeive, and therefore the odulator and the deodulator should be present at both ends. The odulator and deodulator together are alled the ode. Carrier odulation an be broadly divided into two ategories Analog (Continuous Wave) odulation Digital odulation The various analog odulation tehniques are: Aplitude odulation (AM) Frequeny odulation (FM) Phase odulation (PM) Angle odulation The various digital odulation tehniques are: Aplitude shift keying (ASK) Frequeny shift keying (FSK) Phase shift keying (PSK) Types of Analog odulation (i) (ii) (iii) Aplitude odulation Frequeny odulation Phase odulation Priniples of Aplitude odulation Aplitude odulation (AM) is a tehnique used in eletroni ouniation, ost oonly for transitting inforation via a radio arrier wave. AM works by varying the strength of the transitted signal in relation to the inforation being sent. For exaple, hanges in the signal strength an be used to speify the sounds to be reprodued by a loudspeaker, or the light intensity of television pixels. (Contrast this with frequeny odulation, also

7 oonly used for sound transissions, in whih the frequeny is varied; and phase odulation, often used in reote ontrols, in whih the phase is varied. AM Envelope AM is also alled as AMDSBFC( Double side band full arrier) Carrier V sin t Moulating signalv sin t Modulated signal V a (t) When a single frequeny odulating signal ats on a high frequeny arrier signal. The output wavefor ontains all the frequeny. The fig shows the odulated wave and the shape is alled an envelope. When a odulating signal is applied the aplitude of the output wave varies in aordane with the odulating odulating signal.

8 The repition rate of the envelope is equal to the frequeny of the odulating signal and the shape of the The Envelope: t s A 1 k t The AM Signal t s A 1 k t os t envelope is idential to the shape of the odulating signal. AM frequeny spetru and Bandwidth AM odulator is a nonlinear devie. The nonlinear ixing of the essage and arrier gives an envelope ( i.e. oplex wave ade up of d voltage the arrier frequeny and the su and differene frequenies) An AM signal spetru ontains frequeny oponents spaed f Hz on either side of the arrier. Modulating frequeny Modulated frequeny f arrier frequeny f -f (ax) lower sideband f +f (ax) upper sideband

9 Aplitude arrier LSB LSF USB USF f -f (ax) f f + f (ax) freq Frequeny spetru of AMDSBFC Bandwidth The bandwidth of an AMDSBFC wave is equal to the differene between the highest upper side frequeny and the lowest lower side frequeny. Twie the highest odulating frequeny is defined as bandwidth. B=f (ax) Modulation index and perentage of odulation Modulation index is otherwise alled as o-effiient odulation whih is represented by. Modulation index desribes the aount of aplitude hange present in AM wave (or) ratio between axiu aplitude of odulating signal to the arrier signal E E = odulation o-effiient(unitless) E = Peak hange in the aplitude of the output wavefor (v) E =peak aplitude of the unodulted arrier.(v)

10 It is not pratially possible to onstrut a iruit produing a 100% odulation so in ost of the appliations the under odulation is used. Over Modulation results in the intersetion of the two side band signals, so it is not possible to reonstrut the sae original odulating signal in the deodulator. Perentage odulation The o-effiient of odulation in perentage is alled perentage odulation whih is represented by M M E E 100 Relation aong E, E and ( refer diagra P.no 14- ECS-wayne toasi) The perentage odulation is derived by E E M M v v v v v v ax ax ax ax ax ax v v v v v v in in in in in in 100 V ax =E +E

11 V in =E -E lower side frequenies. The peak hange in the aplitude of the output wave is the su of the voltage fro the upper and E =E USf +E LSf 1 vax vin E E USf =E LSf= 1 v 4 ax v E usf =peak aplitude of the upper side frequenies(v) in E Lsf =peak aplitude of the lower side frequenies(v)

12 AM voltage Distribution The unodulated arrier is given by V C (t)=e C sin f C t V C (t)=tie varying voltage wavefor or the arrier E C =Peak arrier aplitude(volts) F =arrier frequeny(hertz) The axiu aplitude of the odulated wave is equal to E C +E. The instantaneous aplitude of the odulated wave an be expressed as V a (t)=[ E C +E sin f t][sinf t] E C +E sin f t= aplitude of the odulated wave E =peak hange in the aplitude of the envelope(volts) f = frequey of the odulating signal(hz) V a (t)= [1+ sin f t] [E sinf t] [1+ sin f t]= onstant + odulating signal E sinf t =unodulated arrier The onstant oponent produes the arrier oponent in the odulated wave and the sinusoidal oponent produes the side frequenies. V a (t)= E sin f t + [ E sin f t][e sinf t] E E V a (t)= E sinf t - [os ( f f ) t] [os ( f f ) t]

13 The aplitude of the arrier in the first ter is not hanged and the aplitude of the upper and lower sideband is depends on both the arrier aplitude and the o-effiient of odulation. For 100 perent odulation =1, and the aplitude of upper and lower side frequenies are equal to one half of the aplitude of the arrier. E E Vax E E V in E E E 0 V The axiu peak aplitude of an AM envelope V ax =E The axiu peak aplitude of an AM envelope V in =0 V. AM power Distribution The power dissipated is equal to the voltage squared divided by the resistane. The Average power dissipated in a load by an unodulated arrier is equal to the RMS arrier voltage squared divided by the load resistane. Power in unodulated arrier is P (0.707E ) R E = R P = arrier Power in Watts E =Peak arrier voltage (volts) R= load ressitane. The upper and lower sideband powers are expressed atheatially as P usb =P Lsb =(E ) /R

14 P usb = upper sideband power ( watts) P Lsb = lowe sideband power (watts) P usb = P Lsb = 4 E R P P usb = P Lsb = 4 When odulation oeffiient =0, the power in the upper and lower sideband is zero, and the total transitted power is iply the arrier power. The total power in an aplitude odulated wave is equal to the su of the powers of the arrier, the upper sideband and the lower sideband. P t =p _+ P usb +P Lsb P P t =P + P t = 1 P Advantages of AM AM is relatively inexpensive. AM is a low quality for of odulation used for any oerial appliations. Modulation and deodulation are easily done by a non-linear devie like swithing odulator in the transitting side and the envelope detetor in the reeiving side. The deodulated output is sae as the inoing AM wave when M<100%. So it is easy to reonstrut the original wavefor in the reeiver whih is sae as that of the input odulating signal.

15 Disadvantages of AM It has poor perforane in the presene of noise and interferene. Waste of Power: AM has ineffiient use ot transitter power. The two-third of the power is onsued by the arrier for its transission, so it is wasted. Waste of Bandwidth: It requires twie the bandwidth of the essage signal, but both usb and lsb ontains the sae inforation. So it is enough to use only one side band to retrieve the original essage signal. Appliations of AM It is used for oerial broadasting of both audio and video signals. It is also used for two-way obile radio ouniation (itizen band radio). It is used in the broadasting in the ediu and high frequeny bands. It is also used in the airraft ouniations in the VHF frequeny range. Angle odulation Frequeny odulation The lassi definition of FM is that the instantaneous output frequeny of a transitter is varied in aordane with the odulating signal. An equation for a sine wave is e(t) = EP sin(ωt + φ) While aplitude odulation is ahieved by varying EP, frequeny odulation is realized by varying ω in aordane with the odulating signal or essage. Notie that one an also vary φ to obtain another for of angle odulation known as phase odulation (PM). An iportant onept in the understanding of FM is that of frequeny deviation. The aount of frequeny deviation a signal experienes is a easure of the hange in transitter output frequeny fro the rest frequeny of the transitter. The rest frequeny of a transitter is defined as the output frequeny with no odulating signal applied. For a transitter with linear odulation harateristis, the frequeny deviation of the arrier is diretly proportional to the aplitude of the applied odulating signal.

16 An FM transitter is said to have a odulation sensitivity, represented by a onstant, kf, of so any khz/v, kf = frequeny deviation/v = kf khz/v For a single odulating tone of em(t) = em sin(ωmt), The aount of frequeny deviation is given by δ(t) = kf * em(t) Where δ(t) is the instantaneous frequeny deviation and em(t) represents the Modulating signal. The peak deviation is given by δ = kf * EM Where both δ and EM are peak values. Tie display of a Typial FM signal

17 PHASE MODULATION Frequeny odulation requires the osillator frequeny to deviate both above and below the arrier frequeny. During the proess of frequeny odulation, the peaks of eah suessive yle in the odulated wavefor our at ties other than they would if the arrier were unodulated. This is atually an inidental phase shift that takes plae along with the frequeny shift in FM. Just the opposite ation takes plae in phase odulation. The audio frequeny signal is applied to a PHASE MODULATOR in p. The resultant wave fro the phase odulator shifts in phase, the tie period of eah suessive yle varies in the odulated wave aording to the audio-wave variation. Sine frequeny is a funtion of tie period per yle, a phase shift in the arrier will ause its frequeny to hange. The frequeny hange in f is vital, but in p it is erely inidental. The aount of frequeny hange has nothing to do with the resultant odulated wave shape in PM opare the three voltages (A, B, and C). Sine voltage A begins its yle and reahes its peak before voltage B, it is said to lead voltage B. Voltage C, on the other hand, lags voltage B by 30 degrees. In phase odulation the phase of the arrier is aused to shift at the rate of the AF odulating signal. In figure note that the unodulated arrier has onstant phase, aplitude, and frequeny. The dotted wave shape represents the odulated arrier. Notie that the phase on the seond peak leads the phase of the unodulated arrier. On the third peak the shift is even greater; however, on-the fourth peak, the peaks begin to realign phase with eah other. These relationships represent the effet of 1/ yle of an AF odulating signal. On the negative alternation of the AF intelligene, the phase of the arrier would lag and the peaks would our at ties later than they would in the unodulated arrier

18 FM and PM Wavefors The Figure below inludes both frequeny and phase odulations of a sinusoidal arrier by a single frequeny odulating signal. Both FM and PM wavefors are idential exept for their tie relationship (phase). It is ipossible to distinguish FM wavefor fro a PM wavefor without knowing the dynai harateristis of the odulating signal. With FM, the axiu frequeny deviation ours during axiu positive or axiu negative peaks depending upon the type of odulator eployed. The frequeny deviation is diretly proportional to the aplitude of the odulating signal. With PM, the axiu frequeny deviation ours during zero rossings of the odulating signal. Here the frequeny deviation is proportional to the slope or first derivative of the odulating signal. For both FM and PM, the rate at whih the frequeny hanges our is equal to the odulating signal frequeny. We know that (t) = V C Cos [ω C t + θ(t)]. This equation doesn t ean whether it is FM or PM. The orret identifiation is done fro the odulating signal. If θ(t) = K V (t), it is Phase Modulation. If θ(t) = K 1 V (t), then it is Frequeny Modulation. Whenever the instantaneous frequeny of the arrier is diretly proportional to the odulating signal, it is alled FM. When the instantaneous phase is diretly proportional to the aplitude of the odulating signal, it is alled PM. Equations for Phase and Frequeny Modulated Waves Type of Modulation Modulating Signal Angle Modulated Wave a) PM v (t) V C Cos (ω C t + K v (t)) b) FM v (t) V C Cos (ω C t + K 1 v (t) dt) ) PM V Cos (ω t) V C Cos (ω C t + K V Cos (ω t)) d) FM V Cos (ω t) V C Cos (ω C t + K 1 V /ω ) Cos (ω t))

19 FM and PM Wavefors Frequeny deviation and perentage odulation Frequeny deviation is the hange in frequeny that ours in the arrier when it is ated on by a odulating signal frequeny. It is given as a peak frequeny shift in HZ.(f ). The peak to peak frequeny deviation f is also alled arrier swing. The deviation sensitivity of FM is given in Hz/V. The peak frequeny deviation is the produt of the deviation sensitivity and the peak odulating signal voltages and it is given by f K 1 V Hz

20 Modulation Index f f ( t) V ( t) V ( t) V C C C K1V ost f f ost sin t f os t sin t sin t In PM both the agnitude index and the peak phase deviation are diretly proportional to the aplitude of the odulating signal and unaffeted by its frequeny. In FM both the odulation index and frequeny deviation are diretly proportional to the aplitude of the odulating signal and the odulation index is inversely proportional to its frequeny. Vs Aplitude Vs freq Deviation FM PM FM & PM f Phase deviation Vs Aplitude V f Frequeny deviation Vs aplitude PM FM V V

21 Phase deviation and odulation Index The odulating signal (t) is given by ( t) V os t os t (1) C os t instantaneous phase deviation (t) peak phase deviation in rad Peak phase deviation is also alled odulation index. In PM the odulation index is proportional to the aplitude of the odulating signal and independent of its frequeny. The odulation index of the phase arrier is given by =KV rad = Modulation index and peak phase deviation(,rad) K= deviation sensitivity(rad/v) V =peak odulating signal aplitude (volts) ( t) V C os t kv ost ( t) V os t os t C ( t) V os t os t C In Frequeny odulated arrier the odulation index is diretly proportional to the aplitude of the odulating signal and inversely proportional to the frequeny of the odulating signal. K1V ( unitless)

22 K 1 Deviation sensitivity rad/v radian frequeny( rad/se) Deviation sensitivity is expressed in Hz/V whih is given by K V f 1 f yli frequeny(hz/s) Frequeny Analysis of Angle odulated Waves The frequeny oponent of the odulated wave is very oplex. The single odulating frequeny an generate an infinite nuber of sideband whih gives an infinite bandwidth. Modulation by a single frequeny sinusoidal Frequeny analysis of an angle odulated wave by a single arrier frequeny sinusoidal produes a peak phase deviation of radians. ( t) V os t os t C The Bessel funtion is given by os os n jn ( )os n n J n =Bessel funtion of the first kind of the n th order with arguent

23 n n n t n t j V t ) os ( ) ( For the first four ter )... (... ) os ( ) os ( ) os ( ) os ( ) os ( ) ( 1 1 J t J t J t J t J t J V t n o (t) angle Modulated wave Modulation index V =peak aplitude of the unodulated arrier. J 0 ()arrier oponent J 1 ()First set side frequeny displaed fro the arrier by J () seond set side frequeny displaed fro the arrier by J n ()n th set side frequeny displaed fro the arrier by n A single frequeny odulating signal produes an infinite nuber of sets, of side frequenies eah displaed fro the arrier by an integral ultiple of the odulating signal frequeny. A side band set inludes an upper and lower side frequeny. Suessive set of sidebands are alled fist order side bands, seond order side bands, and so on, and their agnitudes are deterined by the oeffiients J1 (), J (), and so on, respetively. Aplitude of the side frequenies, Jn,

24 Table shows the Bessel Funtions of the First Kind for Several Values of the Modulation Index. A odulation index of 0 produes zero side frequenies, and the larger the odulation index, the ore set of side frequenies produed. The values shown for Jn are relative to the aplitude of the un odulated arrier. The aplitude of the higher order frequenies rapidly beoes insignifiant as the odulation index dereases unity. For larger values of, the value of Jn() starts to derease rapidly as soon as n=. As the odulation index inreases fro zero, the agnitude of the arrier J0() dereases. When is equal to approxiately.4, J0() = 0 and the arrier oponent go to zero (first arrier null).

25 This property is often used to deterine the odulation index or set the deviation sensitivity of an FM odulator. The arrier reappears as inreases beyond.4. When reahes approxiately 5.4, the arrier oponent one again disappears (seond arrier null). Further inreases in the odulation index will produe additional arrier nulls at periodi intervals. The above figure shows the urves for the relative aplitudes of the arrier and several sets of side frequenies for values of. It an be seen that the aplitudes of both the arrier and the side frequenies vary at a periodi rate that resebles a daped sine wave. The negative values for J() indiate the relative phase of that side frequeny set. A side frequeny is not onsidered signifiant unless it has aplitude equal to or greater than 1% of the un odulated arrier aplitude. As inreases the nuber of signifiant side frequenies inrease. Consequently, the bandwidth of an angle- odulated wave is a funtion of the odulation index.

26 Bandwidth requireents of angle odulated waves The Bandwidth of an angle odulated wave is a funtion of the odulating signal frequeny and the odulation index. The bandwidth is signifiantly wider beause of the infinite nuber of sidebands. Angle odulation is lassified as Low, Mediu or High index In low index <1 In high index >10 In low index the signal inforation is arried by the first set of sideband and the iniu bandwidth required is approxiately equal to twie the highest odulating signal frequeny so it is soe ties alled as narrow band FM. In high odulation index the bandwidth is deterined by quasi-stationary approah. In this approah it is assued that the odulating signal is hanging very slowly. The iniu bandwidth required to propagate a frequeny odulated wave is approxiately the peak to peak frequeny deviation f For low index the frequeny spetru resebles DSBAM and the iniu bandwidth is B=f. The bandwidth required to pass all signifiant sidebands for an angle odulated wave is equal to two ties the produt of the highest odulating frequeny and the nuber of signifiant sidebands. B ( n f ) Hz n= nuber of signifiant sideband f = Modulating signal frequeny(hz) Carson s Rule (regardless of odulation index) Bandwidth requires to transit an angle odulated wave is twie the su of the peak frequeny deviation and the highest odulating signal frequeny.

27 B ( f f ) Hz f Peak frequeny deviation(hz) f Modulating signal frequeny (Hz) Low odulation f >> f High odulation indies f>>f Carson s rule gives slightly narrow bandwidth than Bessel funtion. It inludes 98% of the total power in the odulated wave.

28 Questions Objetive type Questions 1. a) Aplitude odulation is a odulation. i) Linear ii) Non-linear iii) Ative iv) Passive b) Aplitude odulators are devies. i) Linear ii) Non-linear iii) Ative iv) Passive. a) When there is no odulating signal, the output wavefor of the Aplitude odulator is signal. i) Modulated ii) Modulating iii) Carrier iv) Unodulated b) For 0% odulation, the total transitted power is equal to. i) Signal power ii) Half of arrier power iii) Half of signal power iv) Carrier power 3. a) Diret FM is also alled PM and Diret PM is also alled as FM. i) Diret, Diret ii) Indiret, Indiret iii) Diret, Indiret iv) Indiret, Diret b) Low odulation index FM is also alled as FM. i) Narrowband ii) Wideband iii) Broadband iv) Low 4. a) The unit of deviation sensitivity is. i) Hz/Volt ii) Radian/Volt iii) Hz/Se iv) Both a and b b) is also alled as arrier swing. i) Peak phase deviation ii) Peak frequeny deviation iii) Peak-to-peak frequeny deviation.iv) Peak-to-peak frequeny deviation 5. a) Angle odulation produes bandwidth. i) Infinite ii) Finite iii) Low iv) Mediu

29 TWO MARKS 1. Define aplitude odulation.. Define bandwidth. 3. Define oeffiient of odulation. 4. Draw the AM frequeny spetru. 5. Calulate the total o-effiient of odulation for the odulating signals with o-effiient of odulation 1=0., =0.7 and 3= Define Frequeny Deviation and Carrier Swing. 7. How an you alulate the bandwidth using Carson s rule and Bessel Table? 8. What is eant by Digital Modulation? 9. Define inforation apaity. 10. For any FM transitter with an 80 KHz arrier swing deterine frequeny deviation if the aplitude of the odulating signal dereases by a fator of, deterine the new frequeny deviation. DETAIL 1. Explain the AM generation with the wavefors. Explain the power distribution for an AM wave with power spetru diagra. 3. Explain the AM urrent alulation. 4. Explain the voltage distribution for an A wave 5. Explain the frequeny analysis of angle odulated waves using Bessel identity. 6. Explain the bandwidth requireents of angle odulated waves in detail.