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while demodulating the modulated signal using coherent detection at the receiver end we need to generate the same carrier which is a very difficult ,it makes the receiver costlier and complex because the signal get distorted during the transmission process so generating the same carrier is quite impossible . if we are required to transmit the message to a large number of receivers than it will become very complex and costly.
secondly when we modulate and send a pilot carrier it become possible to detect the signal by envelope detection method which requires very less circuitry and is very cheap. provided the sum of maximum amplitude of carrier and the message signal must be greater than zero so that the envelope gets a lift up..
the disadvantage of this scheme is that the higher transmission power is required...
What else can I help you with?
Why analog data have to be modulated onto an analog signal?
For transmission through a radiowave.
Are digital transmissions modulated over a carrier?
yes for transmission of the signal to take place smoothly,digital tranmission needs to be modulated over a carrier
When you do modulation in time domain you get modulated waveform of modulating signal information and carrier. How can you recognize the upper and lower side bands in time domain modulated waveform?
You need modulation signal(carrier) which is a required signal in order to make envelope of time domained signal(target signal). The modulating signal is imposed on modulation signal.This creates envelope of waveform which is modulated(desired) signal. Now, the desired signals uper and lower sideband of signal strictly depends on modulation signal's bandwidth. Max. peak of that signal is uper sideband and min. peak is lower sideband for this modulated signal.
What is bandwidth required for AM signal?
With full double sideband AM the bandwidth of the modulated signal is twice that of the baseband information signal. With suppressed carrier single sideband AM the bandwidth of the modulated signal is identical to that of the baseband information signal. With vestigial sideband AM the bandwidth of the modulated signal is somewhere between the above two cases, depending on how much of the vestigial sideband is included.
Why is the intelligence signal not in the AM envelope?
The intelligence signal is in the AM envelope.In AM modulation, the carrier is amplitude modulated by the signal. This signal appears as the envelope of the carrier. You can demodulate it by following the peaks on each cycle of the carrier. You can either follow the positive peaks or the negative peaks - it does not matter if the original modulation is symmetrical.
What are the difference between carrier signal modulating signal modulated signal baseband and passband?
carrier signal- use for the purpose of conveying information. modulating signal- causes variations in some characteristics of carrier signal. modulated signal - carrier signal after altration in its characteristics is called modulated signal. example- if you want to see an object (suppose it is an modulating signal),you need light(light is carrier signal) and when light will reflect on object you will be able to see if (that is modulated signal)
When a carrier is phase modulated with an integrated modulating signal the resultant is?
It gives frequency modulated signal
Why analog data have to be modulated onto an analog signal?
For transmission through a radiowave.
Is carrier signal present at output of double side band suppressed carrier?
No, the carrier signal is not present at the output of double side band suppressed carrier. That is what suppressed carrier means. However, the receiver has enough information to regenerate the carrier if need be. The advantage of suppressed carrier mode is that more power can be deployed to the signal-carrying portion of the modulated carrier.
Are digital transmissions modulated over a carrier?
yes for transmission of the signal to take place smoothly,digital tranmission needs to be modulated over a carrier
Why is amplitude of demodulated FM signal much less than modulated signal?
because demodulated FM is an audio signal, which the frequency is much smaller that is why it can be transmitted alone. It need carrier which has large frequency. Modulated signal is an audio signal + carrier that is why the amplitude is higher.
What is lowlevel amplitude modulation and highlevel amplitude modulation?
low level amplitude modulation occurs when the carrier signal is first modulated and then amplified,whereas in high level modulation,the carrier signal is first amplified and then is modulated.
How does demodulator detects modulated wave?
A demodulator detects a modulated wave by separating the modulating signal from the carrier wave. This is done by reversing the modulation process applied to the carrier wave to extract the original signal that was modulated onto it. Different demodulation techniques are used depending on the modulation scheme employed.
When you do modulation in time domain you get modulated waveform of modulating signal information and carrier. How can you recognize the upper and lower side bands in time domain modulated waveform?
You need modulation signal(carrier) which is a required signal in order to make envelope of time domained signal(target signal). The modulating signal is imposed on modulation signal.This creates envelope of waveform which is modulated(desired) signal. Now, the desired signals uper and lower sideband of signal strictly depends on modulation signal's bandwidth. Max. peak of that signal is uper sideband and min. peak is lower sideband for this modulated signal.
How do you send a digital radio signal to a FM radio?
Frequency Modulation must have a carrier whereby the frequency can be modulated by the signal
What is difference between modulated wave and carrier wave?
Carrier Wave: A carrier wave is a high-frequency electromagnetic wave that is used as the "carrier" or the base signal in a modulation process. It is typically a pure sine wave with a constant frequency and amplitude. The carrier wave by itself does not carry any information; it serves as a vehicle to carry the information from one location to another. In AM and FM radio broadcasting, the carrier wave is the primary signal transmitted by the radio station. Modulated Wave: A modulated wave is the result of combining the carrier wave with an information signal, such as an audio signal or data. Modulation is the process of varying the characteristics of the carrier wave (either its amplitude or frequency) in accordance with the information signal. There are two common types of modulation: Amplitude Modulation (AM) and Frequency Modulation (FM). In AM, the amplitude of the carrier wave is varied in proportion to the amplitude of the information signal. This variation encodes the information onto the carrier wave. In FM, the frequency of the carrier wave is varied in proportion to the amplitude of the information signal. This variation encodes the information onto the carrier wave. The modulated wave contains the information that needs to be transmitted, and it can be demodulated at the receiving end to retrieve the original information.
What is fading in telecommunications?
In wireless communications, fading is deviation or the attenuation that a carrier-modulated telecommunication signal experiences over certain propagation media.
