What is the difference between Signaling and Modul

[commtech]

What is the difference between Signaling and Modulation?

Thank you.

[charan langton]

The meaning of modulation is standard but is not straight forward to explain. In simplest terms, it is a way to send intelligent information or a message (which may be in digital format such as a bunch of of 0s and 1s) over a medium. The medium is a radio frequency carrier or any frequency through a physcial medium (such as a wire) that is large compared to the frequency of the message. Your voice would be considered the message and the 900 MHz over which you use the wireless phone is the rf medium. The message is then used to modify the rf carrier ( basically a sine wave). There are many ways to do this (AM, FM, PSK, OFDM, etc.) and they are called modulation. So modulation is the process of changing or modifying the carrier phase, frequency or amplitude with the message. The purpose is to transmit this signal further than it would be possible over the same medium if it had not be modulated. All because a modulated signal travels better over the medium than would the message unmodualted.

Signalling is a very general terms, it can be used for message signals, it can be applied to pilot tones, which are just carriers and myriad of other signals which may or may not be modulated. So its meaning depends on the context. It does not have a standard meaning.

Charan Langton