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A phase modulated wave can be generated from frequency modulator by connecting a ___________ before the modulator and a frequency modulated wave can be generated from phase modulator by connecting a __________ before the modulator.

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  1. Differentiator, integrator
  2. differentiator, high-pass filter
  3. integrator, low-pass filter
  4. integrator, differentiator

Answer (Detailed Solution Below)

Option 1 : Differentiator, integrator
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Detailed Solution

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The output of FM modulator is of form

After passing the modulating signal through the differentiator we give as the input to the frequency modulator, i.e.

The expression of the output signal will be:

The differentiation of the integral will simply give the original signal.

We get a phase modulated signal which is of the form:

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Q1.Which of the following statements about FM detection using PLL circuit are correct? S1: At the error amplifier output, we get demodulated FM output. S2: FM signal is applied to the input of the PLL.
Q2.According to Carson’s Rule, what is the approximate bandwidth required for a VHF/UHF two-way radio signal using FM with a 5 kHz maximum frequency deviation and a maximum audio frequency of 3 kHz?
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Q7.An audio signal s(t) is normalized, whose Fourier transform S(f) is shown in the figure, so that |s(t)| ≤ 1. This signal is to be transmitted using FM with a frequency deviation constant kf = 90 kHz/V. What is the bandwidth required for transmission of the FM audio signal?
Q8.An FM audio signal with single-tone modulation has a frequency deviation of 25 kHz and a bandwidth of 75 kHz. What is the frequency of the modulating signal using Carson's rule?
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Q10.Let a frequency modulated (FM) signal  \(\rm x(t)=A\cos(\omega_ct+k_f\int_{-\infty}^{t}m(\lambda)d\lambda)\), where π‘š(𝑑) is a message signal of bandwidth W. It is passed through a non-linear system with output 𝑦(𝑑) = 2π‘₯(𝑑) + 5(π‘₯(𝑑))2 . Let 𝐡𝑇 denote the FM bandwidth. The minimum value of πœ”π‘ required to recover π‘₯(𝑑) from 𝑦(𝑑) is

More Angle Modulation Questions

Q1.Which of the following statements about the AM detection using PLL circuit is/are correct? S1: It has higher noise immunity than the conventional peak detector type AM detector. S2: The PLL is locked to the carrier frequency of the AM signal.
Q2.Which of the following statements about FM detection using PLL circuit are correct? S1: At the error amplifier output, we get demodulated FM output. S2: FM signal is applied to the input of the PLL.
Q3.According to Carson’s Rule, what is the approximate bandwidth required for a VHF/UHF two-way radio signal using FM with a 5 kHz maximum frequency deviation and a maximum audio frequency of 3 kHz?
Q4.Narrowband FM is used in which of the following applications?
Q5.In a PLL-based FM demodulator, the output of the phase detector is proportional to _______.
Q6.In Frequency Modulation (FM), the carrier wave's _____ varies according to the message signal.
Q7.Which of the following statements w.r.t. FSK demodulation using PLL circuit is/are correct? S1: If the input signal frequency changes, the PLL adjusts its frequency output to match the input frequency. S2: The phase-locked loop is used to track the changes in the frequency of the modulated signal.
Q8.For 8-ary signal or symbol the number of likelihood functions are :
Q9.A modulating signal m(t) = 10cos (2π × 103 t) is amplitude modulated with a carrier signal c(t) = 50cos(2π × 105t). Assume R = 1Ω. Find the carrier power required for transmitting this AM wave.
Q10.In phase modulation, frequency deviation is-
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Q1.Which of the following components is required to detect (demodulate) Pulse Position Modulation (PPM)? a) Pulse Generator b) RS Flip-Flop c) PWM Demodulator
Q2.Which of the following statements about the AM detection using PLL circuit is/are correct? S1: It has higher noise immunity than the conventional peak detector type AM detector. S2: The PLL is locked to the carrier frequency of the AM signal.
Q3.In a 100% modulated AM signal with a carrier power of 100 W, what is the power in the lower sideband?
Q4.Which of the following is NOT a commonly used pulse-shaping filter in communication systems?
Q5.In which modulation technique is the carrier modulated using phase shifts of 0°, 90°, 180°, and 270°?
Q6.What is another name for PWM in communication engineering?
Q7.Which of the following statements about FM detection using PLL circuit are correct? S1: At the error amplifier output, we get demodulated FM output. S2: FM signal is applied to the input of the PLL.
Q8.In PLL as frequency synthesizer, if the crystal oscillator having frequency 500 MHz is passed through divide by 2 network, then the input frequency to PLL is _______ MHz.
Q9.The following block diagram represents which type of signal generation in communication?
Q10.What is a primary application of VSB (Vestigial Sideband) modulation?
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