Radio (Part 2)
In previous lecture we have study about the Radio. Radio is a device with the help of which we can hear the voice which is broadcast form the different broadcast channels. In today’s lecture we will discussed about the AM and FM.
AM and FM
AM stands for Amplitude Modulation and FM stands for Frequency Modulation. AM wave length is more so that AM covers more distance as compare to the FM. On the other hand FM range is less but sound Quality is very good as compare to the AM. The carrier wave used in the transmission of radio signals is modulated in one of two waves. Either the power of the carrier wave is varied to match the pattern of the signals (called amplitude modulation or AM) or the frequency of the carrier wave is varied called frequency modulation or FM).
AM (Amplitude Modulation)
Amplitude modulation was used frequently in the past days. AM modulation is on the basis of Amplitude and we modulated the sound signal by using the Amplitude Modulation. AM wave can travel a long distance because the long medium and short waves used are reflected by the ionosphere to follow the curvature of the Earth. AM modulation is the older communication method but it is still in use, because is more cheaper the FM Modulation and uses less power the FM. Unfortunately much of the electrical interference is also AM which sometimes makes reception rather difficult.
FM (Frequency Modulation)
As we know that FM stands for Frequency Modulation and it is the advanced method from the AM. Frequency modulated waves arc not reflected around the curve of the Earth and can be received only as far as the horizon. FM is high frequency Modulation are not so easily interfered with by outside source due to its high frequency and so produce more satisfactory reception. FM consume more power and technique as compare with AM. The quality of FM reception is also higher because these waves can carry higher frequencies more accurately.
Up tell now we have discussed about the Radio, Radio Transmission, Radio Reception AM and FM. These are all related to radio. In the next coming lecture we will discuss about the ionosphere which is the layer of the Earth's atmosphere that is ionized by solar and cosmic radiation.