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C h a p t e r
BASEBAND PULSE AND DIGITAL
SIGNALING
CHAPTER OBJECTIVES
• Analog-to-digital signaling (Pulse code modulation and delta
modulation)
• Binary and multilevel digitals signals
• Spectra and bandwidths of digital signals
• Prevention of intersymbol interference
• Time division multiplexing
• Packet transmission
3–1 INTRODUCTION
This chapter shows how to encode analog waveforms (from analog sources) into baseband
digital signals. As we will see, the digital approximation to the analog signal can be made as
precise as we wish. In addition, we will learn how to process the digital baseband signals so
that their bandwidth is minimized.
Digital signaling is popular because of the low cost of digital circuits and the flexibility
of the digital approach. This flexibility arises because digital data from digital sources may be
merged with digitized data derived from analog sources to provide a general-purpose communication
system.
The signals involved in the analog-to-digital conversion problem are baseband signals.
We also realize that bandpass digital communication signals are produced by using baseband
digital signals to modulate a carrier, as described in Chapter 1.
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