2007-01-12 03:46:58 · 12 answers · asked by snehal k 1 in Science & Mathematics ➔ Engineering
At the most basic level, the radio broadcasts we hear take place in four stages. First, a microphone converts sound waves into electrical signals. Second, the electrical signal from the microphone changes, or modulates, a radio wave called a carrier radio wave, so that it will contain the sound information. This carrier wave is emitted by the broadcast tower. Third, a receiving antenna on a radio tuned to the proper frequency picks up the carrier wave, which then travels to the receiver or radio. Finally, the receiver detects the modulation in the carrier wave and converts it back into electrical signals. The electrical signals are sent to a loudspeaker, which changes them once again into sound waves.
Sound information -- including pitch and loudness -- is carried by radio waves in one of two ways. Depending on the type of radio station -- AM or FM -- the carrier wave is modified differently. Amplitude modulation, or AM, stations code information in the carrier wave by changing, or modulating, the amplitude, the height of the carrier wave's peaks and valleys. The speed at which the amplitude changes determines the pitch of the sound, and the amount that it changes determines its loudness. In contrast, frequency modulation, or FM, stations alter the frequency of the carrier signal. In this case, the speed at which the frequency changes determines the pitch, and the amount that it changes determines the loudness.
Both these methods of broadcasting radio signals have advantages and disadvantages. Generally, AM carrier waves have much longer wavelengths than FM carrier waves, and as a result, they can bend around obstacles like mountains and buildings better than FM waves and can travel greater distances before the signal fades. However, because information is coded in the amplitude of an AM carrier wave, things such as the hum from nearby appliances and sparks going off in passing cars can influence the amplitude and are more likely to interfere with the wave. Also, any unwanted change in the power of the transmission can cause an amplitude change that will distort the sound the radio produces. Since it is much less likely that the frequency of an FM carrier wave might be accidentally modulated, the quality of the sound is better.
2007-01-12 04:54:08 · answer #1 · answered by namrata00nimisha00 4 · 3⤊ 0⤋
FM is Frequency modulation and AM is Amplitude modulation.
FM radio works the same way that AM radio works. The difference is in how the carrier wave is modulated, or altered. With AM radio, the amplitude, or overall strength, of the signal is varied to incorporate the sound information. With FM, the frequency (the number of times each second that the current changes direction) of the carrier signal is varied.
FM signals have a great advantage over AM signals. Both signals are susceptible to slight changes in amplitude. With an AM broadcast, these changes result in static. With an FM broadcast, slight changes in amplitude don't matter -- since the audio signal is conveyed through changes in frequency, the FM receiver can just ignore changes in amplitude. The result: no static at all.
2007-01-12 12:06:29 · answer #2 · answered by kavitapikle 1 · 1⤊ 0⤋
FM is frequency modulation and AM is amplitude modulation. Both are carried on carrier radio waves which are large electromagnetic waves(20 feet in wavelength).AM changes the amplitude or height of the wave to carry the broadcast and FM changes the frequency, vibrations per second, to carry the broadcast. Music sounds better on FM so most music stations have changed to FM. Voice sounds as good on AM so talk radio, sports and news stations go with AM which will travel further. (Also travel bulletins on freeways)Stations are assigned frequencies that they can broadcast at. most are also directional. Radio waves travel at the speed of light and bounce off the ionosphere.
2007-01-12 13:48:56 · answer #3 · answered by science teacher 7 · 0⤊ 0⤋
Fm and AM are two types of madoulations ,where FM stands for frequency madoulation and am stands for amplitude madoulation.
FM radio stations varies between the frequency of 88 to 108 mhz.
and AM radio stations varies between the frequency of 535 to 1800khz .
2007-01-16 06:37:22 · answer #4 · answered by kuldeep singh 1 · 0⤊ 0⤋
FM stands for Frequency Modulated and AM stands for Amplitude Modulated. FM picks up frequency waves and AM picks up Amplitude waves.
FM HAS MUSIC ... AND ISNT LAME
AM HAS LOTS OF TALK RADIO STATIONS AND IS LAME....
2007-01-12 11:54:17 · answer #5 · answered by ♥ Emily ♥ 4 · 0⤊ 0⤋
FM is freequency modulation AM is amplitude modulation FM is 1 in which the information is carried in frequency of the waves where in AM info is in terms of amplitude of the wave
2007-01-13 13:29:06 · answer #6 · answered by badp 2 · 0⤊ 0⤋
The range of frequencies of the carrier waves.
All FM radio stations transmit in a band of frequencies between 88 megahertz and 108 megahertz.
In the same way, AM radio is confined to a band from 535 kilohertz to 1,700 kilohertz.
2007-01-12 11:54:34 · answer #7 · answered by catarthur 6 · 1⤊ 0⤋
FM stands for Frequency Modulated and AM stands for Amplitude Modulated. FM picks up frequency waves and AM picks up Amplitude waves
2007-01-12 11:54:05 · answer #8 · answered by jj? 3 · 0⤊ 1⤋
FM stands for Frequency Modulated and AM stands for Amplitude Modulated. FM picks up frequency waves and AM picks up Amplitude waves. FM is better than AM.. but Statelite/Digital beat all.
2007-01-12 11:52:21 · answer #9 · answered by ☺мοηѕŁα 2 · 0⤊ 1⤋
FM or Frequency Modulation picks up waves based on frequency
AM or Amplitude modulation picks up waves based on amplitude
2007-01-12 13:26:24 · answer #10 · answered by sushobhan 6 · 0⤊ 0⤋