Overview; What You Learn In This Chapter; If You Need Background References; What This Analyzer Does - Agilent Technologies 89410A Operator's Manual

Digital Demodulation Concepts (Opt. AYA)

Overview

What you learn in this chapter

This chapter contains an overview of digital demodulation (option AYA) and
presents concepts on how the analyzer demodulates digitally modulated signals.
For examples on setting up a digital demodulation measurement and analyzing
demodulated data, see the chapters titled "Using Digital Demodulation" and
"Analyzing Digitally Demodulated Signals''. For examples on creating an ideal
digitally modulated signal and creating a user-defined filter, see the chapter titled
''Creating User-defined Signals''. For key-specific information, refer to online Help,
which is accessed by pressing the [ Help ] key on the analyzer.

If you need background references

The information covered in this chapter assumes a good basic knowledge of digital
demodulation. If you need general information on the subject of digital
demodulation ask your sales representative about the following Agilent
Technologies publications:
l
Application Note 355—Digital Radio Theory and Measurements (Part Number
5091-4777E)
l
Application Note 1298—Digital Modulation in Communication Systems-An
Introduction (Part Number 5965-7160E)
l
89400 Product Note 8—Vector Modulation Analysis (Part Number 5091-8687E)
l
89400 Product Note 14—Using Error Vector Magnitude Measurements to
Analyze and Troubleshoot Vector-Modulated Signals (Part Number 5965-2898E)
A number of good text books on the subject of digital communication are available,
for example:
l
Edward A. Lee and Daniel G. Messerschmitt, Digital Communication, Kluwer
Academic Publishers, Boston, 1992

What this analyzer does

This analyzer provides various analysis techniques for several standard and
non-standard digital modulation formats. Analysis capabilities include several
display formats as well as numeric error measurements. Flexible scaling and
markers enhance these capabilities.
This analyzer requires no external filters, coherent carriers, or symbol clock timing
signals. It allows you to demodulate pulsed or continuous carriers and it locks to
the carrier and to a defined symbol rate. The analyzer uses the demodulated signal
to generate an ideal reference signal. The ideal reference signal is compared to the
demodulated signal to provide a quantitative measure of system errors. It has
built-in filters which may be applied to the measured signal as well as to the
reference signal. This allows you maximum flexibility in comparing your signal to
an ideal signal. Additionally, this allows complete flexibility to probe any analog
point in a communication system. An optional second baseband channel allows IQ
baseband measurement capability.
22 - 2