Teledyne Spectrum Analyzer User Manual
Spectrum Analyzer
Software Instruction Manual
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Chestnut Ridge, NY, 10977-6499
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Spectrum Analyzer Software Instruction Manual
© 2012 Teledyne LeCroy. All rights reserved.
Unauthorized duplication of Teledyne LeCroy documentation materials other than for internal
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distribute and duplicate Teledyne LeCroy documentation for their own internal educational
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Teledyne LeCroy and other product or brand names are trademarks or requested trademarks of
their respective holders. Information in this publication supersedes all earlier versions.
Specifications are subject to change without notice.
921324 Rev A
Instruction Manual
Spectrum Analyzer Overview
The Spectrum Analyzer II software simplifies the debugging of frequency-related effects,
presenting a tool kit that mimics the interface of a traditional RF spectrum analyzer. You can
start using the Fast Fourier Transform (FFT) with little or no concern about setting up an FFT.
Key Features
Easy FFT Setup – automatically applies the FFT to your inputs and translates scope sample rate,
memory, and acquisition length settings into frequency domain relevant units. Just choose a
center frequency and span or a start and stop frequency. The resolution bandwidth is
automatically set to optimum resolution (or can be manually controlled).
Peaks/Markers – automatically and continually marks amplitude peaks on the spectrum trace
and displays their values in an on-screen table. Or, you apply moveable markers to the trace,
and the software automatically calculates relative and absolute frequencies and levels.
Spectrogram – displays a 2D or 3D rendering of spectra history.
Method of Operation
Spectrum Analyzer adds two dialogs for frequency analysis to your oscilloscope Analysis
menu options:
Spectrum Analyzer – the principal setup dialog, with controls similar to a traditional RF
spectrum analyzer. This is also where you control the spectrogram.
Peaks/Markers – where you control the Peaks and Markers features.
Set up your spectrum trace on the Spectrum Analyzer dialog by choosing your inputs (one or
more channel, zoom, math, or memory traces) and the frequency range of interest, just as with
an RF analyzer. Then, choose various analysis features, such as Show Peaks or Spectrogram, to
optimize your display.
921324 Rev A 1
Spectrum Analyzer Software
Set Up Spectrum Trace
This procedure explains how to use the Spectrum Analyzer software option to display a
spectrum trace, an FFT of your input trace.
1. Choose Analysis > Spectrum Analyzer; the Spectrum Analyzer dialog appears. Be sure
Enabled is checked so the spectrum trace is displayed.
2. To use 1 Input or a differential probe connected to a single channel (the default), touch
Input1 and choose any channel, zoom, math, or memory source.
OR
To input the difference between two sources, select Input 1-Input 2, then touch Input1
and choose the first source. Repeat for Input2.
Example: You can input the difference between two probes connected to two different
channels. This option eliminates the need to first set up a math trace to calculate the
difference.
2 921324 Rev A
Instruction Manual
Normal (default) – displays the power spectrum of the source trace. You
can enable or disable Persistence in this mode.
Persistence – in Normal mode with Persistence on, you will see a history of
multiple spectra similar to the display on an RF spectrum analyzer.
Average – choose a number of spectra to average. This effectively reduces
noise and displays more of the harmonic carrier detail.
Max Hold – is useful for swept frequency measurements. It shows the
history of peak values across the frequency axis.
3. Position the spectrum trace in either of the following ways:
Select Center Span, then enter the Center Freq. and the Freq. Span, the total range of
frequencies that appear on the grid. Use the Up/Down Arrow buttons to quickly step
through the frequency span.
Tip: To change the frequency span in finer increments than the default 1, 2, 5 steps,
check Variable.
OR
Select Start Stop, then enter the absolute Start Freq. and Stop Freq. of the frequency
span.
Tip: Start by viewing a large range of Start Stop frequencies to see where frequencies of
interest occur in the spectrum trace. Then, Center Span around a frequency for a
smaller span.
Note: The spectrum Analyzer always sets the sample rate equal to or higher than twice
the frequency span selected.
The remainder of the steps are optional.
4. Adjust the resolution by unchecking Auto (the default) and entering a new Resolution
BW.
Note: Changing Resolution Bandwidth is equivalent to changing the Timebase to increase
or decrease memory in FFT mode. Reducing the bandwidth will increase the available
memory, enabling a faster update rate, but will decrease the resolution of the trace.
5. Change the operating Mode of the trace:
921324 Rev A 3
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