Answer 5.1
For a baseband channel, a signalling rate of 2400 baud
would imply a minimum bandwidth of 2400 / 2 Hz. ASK requires twice this bandwidth since
the modulation process generates upper and lower sideband replicas of the baseband signal.
The occupied bandwidth is thus 2400 Hz.
Alternatively we can use the formula,
Cbandpass = B log2M,
where M = 8 and the capacity is 2400 x 3 bps.
Hence B = 2400 Hz.
For a raised cosine filter with a
= 0.5, the bandwidth needed is increased by a
factor (1 + a). This is true for
baseband and bandpass signalling. The new occupied bandwidth is thus 2400 x (1.5)
= 3600 Hz.