0
Bandwidth is defined as difference between two frequencies.
In AM only amplitude is modulated or changed to transmit the data at the given fixed frequency. In FM the frequency of the signal is changed to transmit the data. Since we will need a range of frequency to transmit the data using FM (say frequencies from f1 to f2), the bandwidth of FM signal will be higher than AM signal which can transmit at a fixed frequency.
But.....
The above answer does not address the issue of "strength of modulation", that is, modulation index.
A.M. will always have a bandwidth of twice its highest modulating frequency regardless of the strength of modulation.
For voice comms with about a 3 kHz maximum frequency, A.M. will demand (3+3) = 6 kHz of bandwidth.
Because F.M. modulates the frequency swing of the transmitter, low modulation indexes with F.M. can give a bandwidth LESS than the maximum modulating frequency. Narrow-Band F.M. (NBFM) can have a bandwidth of *less than* 3 kHz, indeed it can have a bandwidth of only a few hundred hertz, in theory.
In practice, very narrow NBFM suffers from worsening signal-to-noise ratios, and one of F.M.'s chief advantages over A.M. is the superior signal-to-noise of F.M. when it is allowed sufficient bandwidth.
Wiki User
∙ 9y ago
Add your answer:
Earn +20 pts
What is the bandwidth of pulse position modulation?
probably (the carrier frequency +- the maximum frequency of the pulse train)/(the carrier frequency) but pulses have a lot of harmonics
Need of modulation in communication?
Need for modulation: 1. Length of the antenna for a transmitter is inversly proportional to the frequency of the signal to be transmitted. So we try shift the frequency of the singal for the transmission to higher frequencies. 2. Every transmission of signal in a bandwidth is assigned with a particular frequency which is attained by modulating the signal with the carrier frequency. Different modulation techniques are implemented according to the requirements and compatibilities
What is narrow band modulation frequency?
When the frequency sensitivity of the modulating signal is small,the bandwidth of the FM is narrow. The narrowband FM has one carrier term two sideband terms.The modulation index is also small compared to one radian.
In frequency modulation what happens to the bandwidth when you increase the modulating frequency?
Bandwidth increases as a function of both modulating frequencyand deviation. As deviation increases, pairs of sidebands are generated, each equal to fc+m and fc-m, fc+2m, fc-2m etc. where fc = the carrier frequency and m = the modulating frequency. Increasing modulation (frequency deviation) will change the level of each of the sideband pairs - and the carrier, which at times falls to zero.
What is Modulation index in Frequency modulation?
Modulation Index is the ratio of the maximum deviation frequency to the frequency of modulation. In other words it is the ratio of the spread in frequency spectrum to the frequency that was used to modulate the carrier. For FM, modulation index is given by the formula mf= df/f where, mf=modulation index for FM df=difference in carrier frequency f=frequency of the signal
Which cellular system uses the most bandwidth efficient modulation?
I think it is Frequency Modulation with Phase modulation which it the most bandwidth efficient
What are the contrast of amplitude modulation to frequency modulation?
AM (Amplitude Modulation) has a smaller bandwidth and can have more stations available in any frequency range. AM is cheaper and can be transmitted over long distances. FM (Frequency Modulation) signals are prone to interference due to physical obstructions. The better sound quality is due to a much higher bandwidth, using FM.
What is the bandwidth of pulse position modulation?
probably (the carrier frequency +- the maximum frequency of the pulse train)/(the carrier frequency) but pulses have a lot of harmonics
Need of modulation in communication?
Need for modulation: 1. Length of the antenna for a transmitter is inversly proportional to the frequency of the signal to be transmitted. So we try shift the frequency of the singal for the transmission to higher frequencies. 2. Every transmission of signal in a bandwidth is assigned with a particular frequency which is attained by modulating the signal with the carrier frequency. Different modulation techniques are implemented according to the requirements and compatibilities
89kHz sinusoidal signal is modulated using an amplitude modulator and a frequency modulator calculate the bandwdith requirement for both modulation schemes?
You can't do this unless you know more detail on the frequency modulator, like its modulation index, for example or the frequency deviation. For the amplitude modulator, it is easy. Bandwidth is twice the signal frequency so in this case the bandwidth is 178kHz for AM.
Is low bandwidth signal has more power than high bandwidth signal?
no,because generally the lower frequency side existed for lower bandwidth,and higher frequency side existed higher bandwidth,so thus we can say that lower bandwidth has generally has lower power as compared to higher bandwidth.
What does FM stand for in radio frequency?
FM means Frequency Modulated.FM stands for modulation on frequency or frequency modulation.
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 narrow band modulation frequency?
When the frequency sensitivity of the modulating signal is small,the bandwidth of the FM is narrow. The narrowband FM has one carrier term two sideband terms.The modulation index is also small compared to one radian.
In frequency modulation what happens to the bandwidth when you increase the modulating frequency?
Bandwidth increases as a function of both modulating frequencyand deviation. As deviation increases, pairs of sidebands are generated, each equal to fc+m and fc-m, fc+2m, fc-2m etc. where fc = the carrier frequency and m = the modulating frequency. Increasing modulation (frequency deviation) will change the level of each of the sideband pairs - and the carrier, which at times falls to zero.
What is the difference between frequency modulation and phase modulation?
The difference between frequency modulation and phase modulation is that with frequency modulation the angular frequency of the signal is modified while with the phase modulation, the phase angle of the signal is modified.
Smaller the pulse width larger is the bandwidth How?
For the Radar Case: The bandwidth of the pulse is the reciprocal of the Pulse Duration (called Pulse Width) as any filtering needs to be able to detection and follow the pulse shape and its edges. The pulse width is the AM modulation to a Fixed Frequency Carrier Frequency and the AM modulation will be greater bandwidth then the Carrier Frequency. As you are attempting to reject receiving other emissions and noise that do not match your own emissions such that your receiver is "match filtered" to your emissions, your receiver bandwidth will be at least the reciprocal of the pulse width but is lightly to be a smaller bandwidth then the reciprocal of the pulse width.
