Agilent Technologies 22A Especificaciones descargar pdf (Pagina 105)

105

Digital modulation analysis

The common wireless communication systems used throughout the world

today all have prescribed measurement techniques defined by standards-

development organizations and governmental regulatory bodies. Optional

measurement personalities are commonly available on spectrum analyzers

to perform the key tests defined for a particular communication format.

For example, if we need to test a transmitter to the Bluetooth wireless

communication standard, we must measure parameters such as:

• Average/peak output power

• Modulation characteristics

• Initial carrier frequency tolerance

• Carrier frequency drift

• Monitor band/channel

• Modulation overview

• Output spectrum

• 20 dB bandwidth

• Adjacent channel power

These measurements are available on the Agilent ESA-E Series spectrum

analyzer with appropriate options. For more information on Bluetooth

measurements, please refer to Agilent Application Note 1333, Performing

Bluetooth RF Measurements Today, literature number 5968-7746E. Other

communication standards-based measurement personalities available on

the ESA-E Series include cdmaOne and GSM/GPRS/EDGE.

Measurement capabilities for a wide variety of wireless communications

standards are also available for the PSA Series spectrum analyzers.

Optional measurement personalities include:

• GSM/EDGE

• W-CDMA

• HSDPA

• cdma2000

• 1xEV-DO

• 1xEV-DV

• cdmaOne

• NADC and PDC

• TD-SCDMA

Figure 8-4 illustrates an error vector magnitude (EVM) measurement

performed on a GSM/EDGE signal. This test helps diagnose modulation

or amplification distortions that lead to bit errors in the receiver.

Figure 8-4. EVM measurement results and constellation display

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Agilent Technologies 22A Especificaciones Pagina 105