Principles of Synchronous Digital Hierarchy

118 Principles of Synchronous Digital Hierarchy

where Rs is the symbol rate (also called Nyquist rate). (Do not confuse this

with the Nyquist’s sampling theorem, which states that any signal can be

faithfully reconstructed from its samples if the sampling is done at twice the

maximum frequency of the signal. This theorem is used for analog-to-digital

[A/D] and digital-to-analog [D/A] conversion. The subject under discussion

here is, however, the transmission of symbols without ISI and not A/D or

D/A conversion.)

In Figure 6.3, take note of the shape of the square pulses after passing

through the band pass lter. Besides the main ...