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Consider the following statements regarding modulation : 1. The communication systems, where a weak signal is transmitted by the use of a modulation is essential in carrier signal. 2. When the frequency of the high frequency signal is varied in accordance with the intensity of the low-frequency weak signal, the modulation is said to be frequency modulation. 3. The process of recovering original baseband signal from the modulated signal is called phase modulation. Which of the above statements are correct ? 

Consider the following statements regarding modulation : 1. The communication systems, where a weak signal is transmitted by the use of a modulation is essential in carrier signal. 2. When the frequency of the high frequency signal is varied in accordance with the intensity of the low-frequency weak signal, the modulation is said to be frequency modulation. 3. The process of recovering original baseband signal from the modulated signal is called phase modulation. Which of the above statements are correct ?  Correct Answer 1 and 2 only

Modulation:

  • Modulation is the process of varying one or more properties of a periodic waveform, called the carrier signal, with a separate signal called the modulation signal.
  • The modulation signal contains information to be transmitted.
  • For example, the modulation signal might be an audio signal representing sound from a microphone. The carrier is higher in frequency than the modulation signal. (Statement 1 is correct)
  • Modulation techniques are commonly classified into continuous wave (CW) modulation and pulse (PU) modulation. 
  • While modulation takes place at the transmitting end of a communication system, an inverse operation called detection needs to be performed at the receiving end. (Statement 3 is incorrect)
  • Detection aims at recovering the information-bearing signal from the received signal as close as possible.

 

Frequency Modulation:

The frequency of the carrier is varied according to the amplitude of the message signal or the intensity of light. (Statement 2 is correct)

This is explained with the help of the following diagram:

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[ alt="F1 S.B Madhu 06.02.20 D2" src="//storage.googleapis.com/tb-img/production/20/02/F1_S.B_Madhu_06.02.20_D2.png" style="width: 335px; height: 157px;">

[ alt="F1 S.B Madhu 06.02.20 D3" src="//storage.googleapis.com/tb-img/production/20/02/F1_S.B_Madhu_06.02.20_D3.png" style="width: 404px; height: 167px;">

Related Questions

Which of the following is/are correct? 1. Detection is the process of recovering the modulating signal from the modulated carrier wave. 2. The carrier frequency is usually changed to a lower frequency by what is called an intermediate frequency (IF) stage preceding the detection.
Which of the following is the process of recovering modulated signal from the modulated carrier wave?
A GSM cellular telephone standard requires a minimum of 9 dB rejection of interfering signal levels of -23 dBm at 3 MHz from the carrier, -33 dBm at 1.6 MHz from the carrier, and -43 dBm at 0.6 MHz from the carrier, for a carrier level of -99 dBm. Determine the required local oscillator phase noise at 3 MHz carrier frequency offset.
Consider the statements given below and select the correct statement(s)
1. Computer-mediated communication (CMC) is defined as any human communication that occurs through the use of two or more electronic devices.
2. Computer-mediated Communication can be broken down into two forms i.e. synchronous and asynchronous.
3. Synchronous computer mediated communication refers to communication which occurs in real time.
4. Asynchronous computer mediated communication refers to communication which takes place when the parties engaged are not communicating in unison.
Which of the following set of statements are correct for describing the human communication process?
1. Non-verbal communication can stimulate ideas.
2. Communication is a learnt ability.
3. Communication is not a universal panacea.
4. Communication cannot break down.
5. More communication means more effective learning by students.
6. Value of what is learnt through classroom communication is not an issue for students.
Select the correct answer
A 2 MHz carrier is amplitude modulated by a 500 Hz modulating signal to a depth of 70%. If the unmodulated carrier power is 2 kW, the power of the modulated signal is
Consider the following types of modulation: 1. Amplitude modulation 2. Frequency modulation 3. Phase modulation 4. Pulse modulation Which of the above modulation are used for telecasting TV programs?
Which of the following is used to vary the frequency of the carrier frequency in accordance with the baseband signal amplitude variations in direct method of FM generation?
The process of recovering base band signal from high frequency modulated signal is called
Frequency modulated signal is regarded as the phase modulated signal in which the modulating wave is differentiated before modulation.