7 ms·
Hehe, happens :) But, suppose the sun did interfere - how would you filter this out? Due to the black-body nature of the source, the amplitude would be stable,
by deogeo 7y ago
Hehe, happens :)
But, suppose the sun did interfere - how would you filter this out? Due to the black-body nature of the source, the amplitude would be stable, but the phase wouldn't be - you'd get entirely uncorrelated white noise, right? How can you filter that?
- Dylan16807 7y agoI've never really looked into how the encoding is typically done on those bands. You don't need a lot of bits per Hz when you have 14GHz of space, so nothing particularly elaborate with phase is strictly necessary. But yes it would definitely hurt speeds, and you have a good point in that it's something to consider as a sanity check!
- itcrowd 7y agoGood question. A good but short answer is given on Wikipedia (https://en.wikipedia.org/wiki/Matched_filter#Matched_filter_in_digital_communications https://en.wikipedia.org/wiki/Matched_filter#Matched_filter_...). Any undergraduate textbook on digital signal processing should have details on this topic. edit: to add to this, the capacity C ("throughput") of the communications channel is linear with bandwidth B (in Hertz) but only logarithmic (log_2) with noise power N. This was derived by Shannon (https://en.wikipedia.org/wiki/Shannon%E2%80%93Hartley_theorem#Statement_of_the_theorem https://en.wikipedia.org/wiki/Shannon%E2%80%93Hartley_theore...) and in equation form: C = B*log_2(1+S/N) Example: signal to noise ratio is 1 (S/N = 1). Result: C = B Now we increase the bandwidth of our channel by a factor of 10, keeping the signal power equal. This will lead to a factor 10 more noise power (S/N = 1/10). Result: C = 10*B*log_2(1 + 1/10) = 1.38*B So we can improve the channel capacity by increasing the bandwidth even in a noisy channel.