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NS: (1) Question No. 1 is compulsory
(2) Solve any three from remaining five Questions.
(3) Figures to the right indicate full marks.
Q1.
A: Draw input and output characterstics of BJT. State significance of DC load line. 5
B: For an AM DSBFC modulator with carrier frequency fc = 100KHz and a maximum
Modulating signal frequency fm = 5KHz, determine 5
i) Frequency limits for the upper and lower side bands
ii) Bandwidth
iii) Draw the frequency spectrum
C: Write a note on zero crossing detector using omp-amp and waveforms. 5
D: Compare class A and Class C amplifiers. 5
Q2.
A: Explain Superhetrodyne receiver with suitable diagram. 5
B: Implement summing operational Amplifier using inverting configuration of Op-amp. 5
C: For the emitter bias network of figure below, determine: 10
(a) Ib, (b) Ic, (c) Vce- (d) Vc+ (e) Rth
Q.3
A: Explain generation of DSBSC using balanced Modulator along with its frequency
And power spectrum 10
B: With suitable waveforms explain how op-amp can be used as Differentiator 10
Q4.
A: For an AM DSBSC envelope with Vmax = 20V and Vmin = 4V; determine: 10
i) Peak amplitude of USF AND LSF
ii) Peak amplitude of carrier
iii) Peak change in the amplitude of envelope
iv) Modulation coefficient
v) Draw the AM Envelope
B: Differentiate between TDM and FDM 5
C: State Shannon’s Theorem and explain its significance 5
Q5.
A: Draw PAM, PWM and PPM waveforms in time domain using a sinusoidal signal
And explain in brief. 10
B: Define and explain in brief Amount of information, average information, information
Rate and channel capacity of a communication system. 10
Q6.
A: State significance of modulation in Communication. 5
B: Write a note on Pluse Code Modulation with waveforms. 5
C: Explain and give ideal values of following parameters of an Op-Amp: 10
i) CMRR
ii) Slew rate
iii) Offset Voltage
iv) Input Resitance
v) Output Impedance