0
FM or frequency modulation is a means to vary the frequency withing a set basic frequency and transmit it. FM radio demodulate the frequency extracting the signal that made the frequency shift at the source.
Wiki User
∙ 14y ago
Add your answer:
Earn +20 pts
What is the need for limiter in FM receiver?
The limiter clips the top and bottom of the FM signal to remove any AM signal or static that was picked up. This prevents the FM discriminator from seeing those unwanted signals and inadvertently converting them to audio, scrambling the intended audio signal. Simply put, the limiter blocks interference and static making FM reception very clean.
What is the difference between FM transmitters?
Fro transmitting FM signals from one point to another,one need to have a full system that transforms your signal. The FM transmitter and FM modulator are two parts of this system and they are both necessary in making the system function as desired. The transmitter is the part that dissipates the FM signal into the air so that it can be received by antennas somewhere else. The FM modulator, on the other hand, is responsible for piggybacking the signal onto the carrier signal. Refer american-writers.org for more information.
What is narrow band and wide band FM and How it can be generated?
In frequency modulation system, the maximum usable deviation be fixed +- 5 KHz and test deviation be kept 60% i.e. 3 KHz for wireless telephony systems used in military and other organisations. But wide band fm systems used in commercial broadcasts having frequency deviation +- 75 KHz.
Why power amplifier used in FM transmitter?
Amplifier is used in an FM transmitter to increase the level of a signal suitable for transmission
Why we need high power to generate AM signal and low power to generate FM signal?
The reason FM has lower power and AM has higher power is because the more power that an AM signal has, the farther it will go, but FM does not work that way. AM waves can bounce off of the atmosphere, especially at night. This is the reason that you can hear AM stations from far away at night. FM, on the other hand, can't bounce. FM waves only go in a straight line from the tower and no matter how much power you transmit with, an FM wave will only go a short distance. AM Waves can travel through trees and buildings, and FM can't.
What is the wave width of an FM radio wave?
2(frequency deviation+signal frequency)
What is indirect method of FM transmitter?
indirect FM transmitter is the transmitter which indirected connectly to the FMINDIRECT FM GENERATIONWhile it is not possible to vary the frequency of a crystal oscillator directly, it is possible to vary its phase. The resulting PM signal can be used to create FM. This is the basis of the Armstrong modulator.The mathematics required to analyze the Armstrong modulator completely are complex, so we will discuss only the basic circuit operation. An audio signal is passed through a preemphasis network and then an integrator, a special network whose output is the time integral of the input signal. The preemphasized integrated signal is used to phase modulate a crystal oscillator. Mathematically, it can be shown that PM using the integral of the audio signal is identical to FM using the audio signal itself. In this way an FM signal is generated.The Armstrong modulator cannot produce much deviation, so combination of multipliers and mixers are used to raise the carrier frequency and the deviation. The multipliers are used to multiply the carrier and the deviation. The mixers are used to decrease the carrier, while keeping the deviation constant so that additional multiplier stages can be used to obtain more deviation. It is worth going through an example:An FM station is authorized to operate at 90.9 MHz, with maximum deviation of 75 KHz. The FM signal is generated with an Armstrong modulator whose output is 500 KHz with a deviation of 15.432 Hz. The modulator output is applied to 3 triplers and a doubler to obtain a frequency of 81 MHz and a deviation of 2.5 KHz. The 81 MHz signal is mixed with a 77.97 MHz signal to produce a 3.03 MHz signal whose deviation is still 2.5 KHz. This signal is fed through a doubler, tripler and quintupler to multiply the carrier to 90.9 MHz and the deviation to 75 KHz.
What is the effect of varying frequency of the carrier signal on the AM wave?
spread spectrum , modulation or depending on the bandwidth poss FM (deviation)
What is difference between amplitude modulation and frequency modulation with respect to signal to noise ratio?
In FM noise is low as compared to AM. The AM signal covers more distance than FM signal that's why it gets more distorted.How ever the information in AM signal does not lose but the noise effects it more than that of FM signal,so we get signal with more noise than that of FM signal For FM Carson's rule Main article: Carson bandwidth rule A rule of thumb, Carson's rule states that nearly all (~98%) of the power of a frequency-modulated signal lies within a bandwidth of where , as defined above, is the peak deviation of the instantaneous frequency from the center carrier frequency . Noise quieting The noise power decreases as the signal power increases; therefore the SNR goes up significantly. Thanks, By tauseef ahmed
What characteristic of an audio tone determines the percentage of modulation of an FM broadcast transmitter?
Only the amplitude of the audio tone determines the percentage modulation of an FM transmitter
Differentiate FM signal from AM signal?
FM = Frequency Modulation; AM = Amplitude Modulation; each being a technique by which the speech signal is imprinted onto the carrier signal (the one to which you tune the radio). FM is a higher frequency than AM. FM also only uses the 2.7hz upper side band of the frequency while AM utilizes the entire 6hz both the LSB, USB and the .6hz carrier wave. That allows AM to travel farther than a FM signal.
Why you convert FM signal to IF frequency?
Mix it with a local oscillator whose frequency is (the IF frequency) away from the frequency of the FM signal you're interested in.
Why inTV broadcasting video signal is trancemitted in AM but audio signal is in FM?
AM was used for the video signal because components to transmit and receive the video signal (tubes, originally) were not available that could modulate the frequency fast enough for the amount of information required for a video signal. The VHF band, where most of television broadcasts resided until the the adoption of Digital Television (DTV) was also being used for FM audio broadcasts.
How is FM transmitted?
the digital signal is converted to analog signal after using by transmitted antenna
Why are FM tones used in ASSR?
boz there is lesas interferance to the signal as a signal travels...............
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.
Why FM is good than am in communication?
The FM signal is more amune to static in the atmosphere than AM signals.
