pulses of duration less than carrier cycle

[fisico32]

Hello Forum,

after reading the tutorials on amplitude modulation (ASK) I am wondering it it is possible to create pulses whose duration is less than a cycle of the carrier signal....

I believe it is possible but I am not sure if it is useful....If not ,why not?

Thanks!
fisico

[manzana]

(Non expert... other views welcomed...) I would say "it depends". In classical AM the modulating frequency is much lower than the carrier frequency so a high-frequency pulse would get eliminated by the front end of the receiver. This is like the AM band of your car radio. Your receiver is very good at eliminating frequencies which are not near the one you are using so lots of stations can use the band. But it is absolutely possible to modulate each cycle of the carrier. This is really baseband communication. I have a good example of it on my desk here. It is an intercom which modulates the 60 cycle power line with my 2000 cycle (or so) voice and works great. It is very useful! manzana