Meaning of am and fm (what are they, concept and definition)

What are AM and FM:

AM and FM, in the broadcasting world, are acronyms that refer to two ways of modulating the carrier wave of electrical signals. AM stands for 'amplitude modulated', while FM stands for 'frequency modulated'.

AM or amplitude modulated

AM stands for Amplitude Modulated or Amplitude Modulation; It is a technique used in electronic communication that consists in varying the amplitude of the radio frequency carrier wave. As such, it was the first technique that was used to make radio.

The AM channel has a bandwidth that is between 10 KHz and 8 KHz. Because they are lower frequencies, the wavelengths of which are longer, the range of your signal is considerably wider relative to that of the modulated frequency.

In this sense, AM waves can measure between 100 meters (3000 KHz) and 1000 meters (300 KHz). This is the type of wave that reaches and bounces off the ionosphere.

However, the sound quality of the modulated amplitude (AM) is well below that of the modulated frequency (FM). Furthermore, since they are low-frequency waves, they are more vulnerable to noise, since they occur in the amplitudes of the waves. Despite this, it is the most advisable type of wave for mountainous areas.

FM or frequency modulated

FM stands for modulated frequency; It is a technique that allows information to be transmitted through a carrier wave, varying its frequency. As such, it was patented in 1933 by the American inventor Edwin Howard Armstrong.

The modulated frequency channel has a bandwidth of 200 KHz. Such width allows transmitted sounds (music and speech) to be higher fidelity and quality, and to be cleaner and clearer than in modulated amplitude.

In modulated frequency, one station transmits on 101.1 MHz (that is, 101,100 KHz), and the next one does it on 101.3 MHz (that is, 101,300KHz). This means that between one channel and another 200 KHz are free. In addition, it allows sending a double signal, that is, a stereo signal.

However, the range of the frequency modulated signals is less than that of the modulated amplitude. This is because the modulated frequency is transmitted between 88 and 108 MHz, that is, at very high frequencies, whose waves can measure between one meter (300 MHz) and ten meters (30 MHz). This type of waves, in addition, have considerably small lengths, so that they move in a straight line and attenuate quickly. Hence, it is an ideal wave type for flat areas, where waves can be transmitted without obstacles.