what is harmonics?

[Nokia]

can someone give me the principle or tutorial about what harmonics is sa communication and broadcasting? Nabasa ko sa internet na given a frequency f, its harmonic is 2f 3f 4f and so on.... how come po naging ganun tsaka bakit may ganun? And also is it good or bad?

[mArKhAo]

from wiki:

http://en.wikipedia.org/wiki/Harmonic


may 2 types nyan,

desired(frequency multiplication) tsaka ung undesired(harmonic distortion), madaming important role yan sa field of coms, sa oscillation, modulation, etc...

may mga mganda ding books na mas maiintindihan mo ito, like blake and tomasi

[rommelpm]

Some effects are favorable and some are not depending on the application.

In the field of music, Harmonics played an important role. It gives certain quality to a certain instrument.
A saxophone would sound differently from a flute, because they inherent certain harmonics that distinguish them from the other.

Just for an example, try to listen to a LIVE music and compare it to the one you hear from your home audio system. The sound that is produced by your audio system is much different than that of a live music because some harmonics needed to complete the quality of sound were no longer present.

In the field of Power Electronics, harmonics that are being emitted by the switching process of these power supplies are suppressed and kept to a minimum level as not to interfere with the surrounding equipments.

These are just a few of what I have observed.   

[1-Lucio]

there is another kind of false radio frequencies. These are called HARMONICS. When a transmitter creates an audio or radio frequency, it also creates multiples of that frequency. For example, if a person transmits on the frequency 155.010 MHz, that transmission can be heard on 310.020 MHz, 465.030 MHz, 620.040 MHz, 775.050 MHz, and so on. If you do a little multiplication, you can see that the frequencies are indeed multiples of the first frequency (155.010 * 2 = 310.020, 155.010 * 3 = 465.030, etc.).

Harmonics are strongest on the odd multiples (3, 5, 7, 9, etc.).