3 ms·
That's why they call it "bandwidth" - the width of the spectrum band is what determines the information throughput. Wikipedia might work as a primer. See Nyqu
by samcheng 11y ago
That's why they call it "bandwidth" - the width of the spectrum band is what determines the information throughput.
Wikipedia might work as a primer. See Nyquist & Shannon:
https://en.wikipedia.org/wiki/Nyquist%E2%80%93Shannon_sampling_theorem#Sampling_of_non-baseband_signals https://en.wikipedia.org/wiki/Nyquist%E2%80%93Shannon_sampli...
For example, in order to sample the FM radio signals in the
frequency range of 100-102 MHz, it is not necessary to
sample at 204 MHz (twice the upper frequency), but rather it
is sufficient to sample at 4 MHz (twice the width of the
frequency interval).
- typon 11y agoWhen I first learned this it blew my mind at it's implications and then obviousness. Shannon was a once-in-a-century genius...in a century of many once-in-a-century geniuses.
- ucaetano 11y agoAlso take a look at spectrum efficiency, which is the "practical implementation" of all this. It really helps to understand how spectrum is a limited public resource. For example, a carrier with 20MHz of spectrum each way and a tower covering 1km2 in 3 sectors could offer at most 60Mbps down over 3G. If you have 6000 customers in that same area (remember that some cities have densities in the 10+k/km2), that means ~10Kbps per customer on average, which is enough for 1.5 GB/month/customer.