Re:Nobel Prize in Physics goes to Francis Halzen
by rramadass on Wednesday October 07, 2026 @12:30AM
(#49988195)
Nice. Trying to read/understand "RF Systems and Modulation" is what got me interested in this subject in the first place.
So in my mind i map your comment as; the "carrier signal" single analog frequency is the infinitely repeating regular wave (no information) traveling at v(p) while the "information signal" (analog/digital) imposed on top of it (frequency/amplitude/phase modulation) creates the informational pulse/wave packet traveling at v(g).
Add in different media in the real world and you have a difference between v(g) and v(p) - https://news.ycombinator.com/item?id=49988070
The deviation caused by uncertainty in the package arrival time is typically extremely short, but not zero, for finite signals.
The actual "entity" that is restricted to be <=c is "information velocity". An infinitely repeating pattern would have travel at (phase velocity)=c ... but would ironically transmit no actual information (the bit value is restricted to 1, not 0 or 1).