The discussion revolves around the nature of signals in wave physics, particularly focusing on what constitutes a signal, the distinction between phase and group velocities, and the implications of these concepts in various contexts such as radio transmissions and optical communications.
Participants express varying levels of understanding regarding the definition of signals and the implications of group and phase velocities. There is no consensus on the precise nature of signals or the best way to conceptualize them in wave physics.
Some discussions may depend on specific definitions of signals and the context in which they are applied, such as radio versus optical communications. The implications of dispersion and group delay distortion are noted but not fully resolved.
I don't understandberkeman said:
Please post links to the reading you have been doing so far to try to learn about this subject. We can help you a lot more if you show your efforts to figure out your questions, and ask *specific* questions about your reading. Show your efforts please...Ahmed1029 said:
I'm Reading modern optics by Fowles, but he doesn't really discuss this in his book. He just remarked that signals travel at group velocity and said no more, so I wanted to investigate what signals actually mean and what can be considered a signal. I searched for definitions online, but those weren't detailed enough so I thought someone might be able to help me here.berkeman said:
https://en.wikipedia.org/wiki/Group_velocityAhmed1029 said:
A signal is information. The presence of a single wave is actual information that the 'source' is switched on. The state 'on-off-on-off', with a switch, will transmit/carry useful binary information as with Morse Code etc. The amount of information governs the bandwidth occupied by a signal. It is worth while discussing this in terms of Radio Transmissions although it applies for all non-continuous waves. I find the optical equivalent less approachable - except for optical communications, of course.Ahmed1029 said: