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.