Continuous-Time to Discrete-Time channel

[urwelcome]

two dimensional symbols per second 2d/s

""""A continuous-time channel with bandwidth W Hz available for transmission, the discrete -time model contains W two-dimensional symbols per second (2D/s).""""

In above statement I dont understand what does two dimensional symbols mean and and why in Discrete Time this two-dimensional symbols per second (2D/s).

If somebody can explain it ,it will be great of him.

thanks

 

[vanjula]

The author might have tried to explain by this that :

A discrete time signal need not be digital of just two levels , a simply sampled signal is basically the discrete signal ...

Now, you know samples have different values in terms of amplitude at different time intervals , so , the signal is plotted in two dimensions that is amplitude of sample versus time interval in which they occur . That is , a 2D discrete signal means a sampled signal with graph plotted between amplitude and time interval ...

and , it is given that "W" number of such samples are being transmitted in a second and hence he has given the transmission rate of the discrete signal ...

I hope you got it now ...