Manipal University 2007 B.E Biomedical Engineering FIFTH SEMESTER MAKE-UP S –- Question Paper

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(a)    An audio frequency signal 10sin(2n * 500/) is used to amplitude modulate a carrier of50sin (2n * 10⁵ t) Calculate

(1)    Modulation index

(2)    Side band frequencies

(3)    Amplitude of each side band frequencies

(4)    Bandwidth required

(5)    Total power delivered to the load of 600Q

(b)    Explain how square law detector is used to detect the following signal x(t) = (l + m cos w_mt )cos w_ct

(a)    Find the carrier & modulating frequencies, the modulation index, and the maximum deviation of the FM wave represented by the voltage equation,

V = 12cos(6 * 10⁸1+ 5sin (l250t )).What Power will this FM wave dissipate in a 10Q resistor?

(b)    Show that the bandwidth of an FM wave is given by the equation, B=2(P+1)f_m where P is the modulation index and f_m is the frequency of the modulating signal.

(a)    Explain the working of DPSK transmitter and DPSK receiver.

(b)    Explain in detail the different blocks in the PCM transmitter, transmission path & the PCM receiver.

(a)    Show that the square law detector is at a disadvantage for below threshold condition.

(b)    Prove that the figure of merit of the synchronous demodulator for the DSB-FC is always less than 1.

(a)    Derive the equation for the output signal to noise ratio of a FM detector for the condition signal power>>noise power.

(b)    Compare the performance of the FM & AM demodulators in the presence of white noise.

(a)    Explain in detail about the implanted transmitters & materials used in Biotelemetry.

(b)    Explain how telemetry is used in the care of critically ill patients.

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