- #1
oneamp
- 219
- 0
I read this:
=====
Nyquist Interval of the opening chapter Historical Background:
"If the essential frequency range is limited to B cycles per second, 2B was given by Nyquist as the maximum number of code elements per second that could be unambiguously resolved, assuming the peak interference is less half a quantum step. This rate is generally referred to as signaling at the Nyquist rate and 1/(2B) has been termed a Nyquist interval."
=====
I understand how the Nyquist theorem applies to signals that are sampled. I understand aliasing to a certain degree. What I do not understand is how it matters to signals like the telegraph, when there is no sampling going on.
- Why does a channel for things like telegraph, what the bandwidth is? 1 Hz is enough to represent a pulse.
- Why do we worry about the bandwidth of a telegraph, with respect to the number of pulses per time period? These aren't sampled, so how can aliasing occur? Why can't we pulse a million of them a second over 1Hz?
- Related, why does FSK/PSK have an advantage over ASK/OOK? Why not just take 1 Hz of bandwidth and put a carrier up and take it down a million times a second?
Please answer so that I can understand intuitively. I've seen the formulas, but nobody can explain to me why it is that way.
Thank you
=====
Nyquist Interval of the opening chapter Historical Background:
"If the essential frequency range is limited to B cycles per second, 2B was given by Nyquist as the maximum number of code elements per second that could be unambiguously resolved, assuming the peak interference is less half a quantum step. This rate is generally referred to as signaling at the Nyquist rate and 1/(2B) has been termed a Nyquist interval."
=====
I understand how the Nyquist theorem applies to signals that are sampled. I understand aliasing to a certain degree. What I do not understand is how it matters to signals like the telegraph, when there is no sampling going on.
- Why does a channel for things like telegraph, what the bandwidth is? 1 Hz is enough to represent a pulse.
- Why do we worry about the bandwidth of a telegraph, with respect to the number of pulses per time period? These aren't sampled, so how can aliasing occur? Why can't we pulse a million of them a second over 1Hz?
- Related, why does FSK/PSK have an advantage over ASK/OOK? Why not just take 1 Hz of bandwidth and put a carrier up and take it down a million times a second?
Please answer so that I can understand intuitively. I've seen the formulas, but nobody can explain to me why it is that way.
Thank you