Re: need help!!!!!!!!!!
we know that other than passband, all the operations, computations, decision almost everything in the baseband is done on digital signals i.e. digital form of the analog signal.
now the porcess of converting analog signal to digital is done by devices like ADC.
these devices takes the samples of the analog signal as a frequency not lesser than twice the operating frequency of the analog siganl i.e. fs >= 2fm ..
where fs = sampling frequnecy and
fm = frewunecy of the analog signal ..
and this is the minimum criteria .. u can sample at any rate may be 3fm, 4fm ..10fm ... depending on how accurately u want to reconstruct the signal at the other end but with computational overhead. this porcess is called as sampliing
now, if u carry out the sampling at sampling frequency fs<2fm ... u ill have very small number of smaples to recontrsuct the original siganl .. this condition is called as aliasing ...
cheers ...