Agilent Spectrum Analysis Basics - Agilent Technologies
Agilent Spectrum Analysis Basics - Agilent Technologies
Agilent Spectrum Analysis Basics - Agilent Technologies
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Chapter 8<br />
Modern <strong>Spectrum</strong> Analyzers<br />
In previous chapters of this application note, we have looked at the<br />
fundamental architecture of spectrum analyzers and basic considerations<br />
for making frequency-domain measurements. On a practical level, modern<br />
spectrum analyzers must also handle many other tasks to help you accomplish<br />
your measurement requirements. These tasks include:<br />
• Providing application-specific measurements, such as adjacent channel<br />
power (ACP), noise figure, and phase noise<br />
• Providing digital modulation analysis measurements defined by industry<br />
or regulatory standards, such as GSM, cdma2000, 802.11, or Bluetooth<br />
• Performing vector signal analysis<br />
• Saving data<br />
• Printing data<br />
• Transferring data, via an I/O bus, to a computer<br />
• Offering remote control and operation over GPIB, LAN, or the Internet<br />
• Allowing you to update instrument firmware to add new features and<br />
capabilities, as well as to repair defects<br />
• Making provisions for self-calibration, troubleshooting, diagnostics,<br />
and repair<br />
• Recognizing and operating with optional hardware and/or firmware to<br />
add new capabilities<br />
Application-specific measurements<br />
In addition to measuring general signal characteristics like frequency and<br />
amplitude, you often need to make specific measurements of certain signal<br />
parameters. Examples include channel power measurements and adjacent<br />
channel power (ACP) measurements, which were previously described in<br />
Chapter 6. Many spectrum analyzers now have these built-in functions<br />
available. You simply specify the channel bandwidth and spacing, then press<br />
a button to activate the automatic measurement.<br />
The complementary cumulative distribution function (CCDF), showing<br />
power statistics, is another measurement capability increasingly found in<br />
modern spectrum analyzers. This is shown in Figure 8-1. CCDF measurements<br />
provide statistical information showing the percent of time the instantaneous<br />
power of the signal exceeds the average power by a certain number of dB.<br />
This information is important in power amplifier design, for example,<br />
where it is important to handle instantaneous signal peaks with minimum<br />
distortion while minimizing cost, weight, and power consumption of<br />
the device.<br />
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