The difference between S/N, spectral efficiency and capacity?

hi all

i want to find the diferrence between

1. S/N
2. spectral effeciency
3. Capacity

Re: just think?

Hi,
Each parameter is defined separately,but all are related in one form or another.It's like this: S/N is defined as The ratio of Average Signal Power to Noise Power.Generally S/N is measured at the output of the receiver and as per ITU regulations, the S/N that should be acheived at the output of the telephone channel is 50dB.
Now,Spectral Efficiency is also called Bandwidth Efficiency and is defined as Bit rate/Bandwidth.Generally,M-ary PSK signals are more spectrally efficient compared to M-ary FSK signals.
And,finally Capacity refers to Channel Capacity and is defined by Shannon as
C = Blog(1+S/N) where B is the Bandwidth.As the name implies, the Capacity of the Channel describes,how many bits the channel can transmit per sec.with minimum Probability of error.
Hope u got my answer.
Regards
Bhanumurthy.

Re: just think?

thanks for replay

but what the difference between capacity or spectral effeiency and " througput" ?

just think?

Hi,
The Capacity for wireless system is the number of user that can be support under certen (GoS or QoS).

just think?

these r very basic terms u can see them in any book,i sugest bp lathi

Re: just think?

so what is " throuput " ?