1,212
edits
Changes
no edit summary
== Some Pros and Cons of General Modulation Schemes ==
For digital communication in general:
* ASK is very inefficient and susceptible to interference for wireless (but can be useful over fiber optics or copper).
* FSK is less susceptible to errors and interference than ASK because interference is often confined to a specific frequency.
* PSK is the least susceptible to error of these three. In terms of bit error rate (BER), binary PSK is about twice as good as ASK and FSK in the presence of noise, and the BER can be significantly improved through other techniques.
*OFDM can also be used. It is very spectrally efficient.
For analog communication in general:
* AM is efficient in terms of bandwidth and has simple receiver circuit but subjected to amplitude variations due to noise and interference
* FM is less susceptible to interference and noises. But has complex circuits and requires large bandwidth.
* PM is not affected by channel noise but on the other hand it has complex circuit as compare to AM and FM.
For in-depth detail of various modulation schemes you can refer to [http://berk.tc/habsis/mod1.pdf this document].
== Demodulation ==
Demodulation is technique to obtain message signal from the receive signal. Modulation and demodulation go hand in hand. Following block diagram gives a general idea:
[[File:Modulation.png|frame|center]]
----
If you are done reading this page, you can go back to [[Communications Subsystem]]