bandwidth is defined as the difference between the highest frequency and lowest frequency.
amplitude is the distance between the, let's call it a crest and a trough, in a wave.
cycle is the time per wavelength -- (a crest and a trough)
period is the time in seconds to complete a cycle.
frequency is the number of periods in 1 second, measured in hertz.
based on this, i have a few questions i'd like to focus in on.
a signal sent from source to destination can be either analog from a-z, digital a-z, or can start digital, and then is modem'd (modulated/demodulated) at a device (modem) at the source, sent across the medium, and then vice-versa'd at the destination.
my question is how is the digital converted to analog.
my downstream rate, for example, is 32,339,000 bps. so according to the text i'm reading to convert this to analog we need a frequency of N/2, which is ~16,000,000 Hz. I'm just typing this out as I try to figure it out, i'm totally lost at this point. Is this the first harmonic? then they suggest to make the shape of the analog signal look more like that of the digital signal, we need to increase the bandwidth to 3N/2, 5N/2, or 7N/2. are these sub harmonics? (i just made that up) 3rd harmonics, 5th harmonics, and 7th?
so, according to the book, the vertical lines represent infinite frequency, while the horizontal lines represent zero frequency. this really confuses me. the conversion, when anaolog looks to me like an amplitude.
any help is appreciated