|
Posted by Green Xenon [Radium] on June 14, 2008, 4:30 am
If you were Registered and logged in, you could reply and use other advanced thread options
> Green Xenon [Radium] wrote:
>> So back to my question.
>>
>> Wouldn't a baud of 1-symbol-per-second use only 1 Hz of bandwidth
>> regardless of the amount of bits-per-symbol?
>
> Depends on the modulation scheme, but basically yes. However, the
> number of states you can support depends on your noise floor. In order
> to get, say, 32768 bps over a 1 Hz channel, you would need a noise
> margin of:
>
> 32768 = 1 log_2 (1 + S/N)
>
> log_2(1+S/N) = 32768
>
> 1+S/N = 2^32768
>
> S/N = 2^32768-1 ~ 2^32768
>
> log_10 S/N ~ log(2)/log(10) * 32768 ~ 9864
>
> log_10 S/N ~ 9864 B = 98640 dB
>
> Even if you're only limited by quantum noise, this still requires a
> trans-astronomical amount of power.
In the real world, what is the maximum amount of bits-per-symbol that
can be achieved using PSK without exceeding the dynamic range of a phone
line?
| 
Yahoo! 
Google 
Windows Live 
del.icio.us 
digg 
Netscape 
XML site map