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HP 8590 E & L Series Spectrum Analyzers and HP 8591C Cable TV ...

HP 8590 E & L Series Spectrum Analyzers and HP 8591C Cable TV ...

HP 8590 E & L Series Spectrum Analyzers and HP 8591C Cable TV ...

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Example<br />

10 OUTPUT 718;"IP;"<br />

20 OUTPUT 718;"SNGLS;TS;"<br />

30 OUTPUT 718;"VIEW TRA;"<br />

40 OUTPUT 718;"SMOOTH TRA,lO;"<br />

50 OUTPUT 718;"VIEW TRA;"<br />

60 END<br />

Description<br />

SMOOTH Smooth Trace<br />

Initializes spectrum analyzer:<br />

Activates single-sweep mode, takes a sweep.<br />

Stores results of trace A.<br />

Smoothes trace A.<br />

Displays the result.<br />

Each point value is replaced with the average of the values (in measurement units) of the<br />

given number of points centered on it. Increasing the number of points increases smoothing at<br />

the cost of decreasing resolution. If the number of points is an even number, then the number<br />

of points is increased by one. If the number of points is larger than the size of SOURCE, then<br />

the size of SOURCE is used (unless size of SOURCE is even, in which case the size of SOURCE<br />

minus one is used). Smoothing decreases at the endpoints.<br />

The purpose of this function is to perform a spatial video averaging as compared to the<br />

temporal version supplied by the video-average (VAVG) comm<strong>and</strong>. The functions of SMOOTH<br />

<strong>and</strong> VAVG are not interchangeable however. Unlike VAVG, SMOOTH averages values that occur<br />

before <strong>and</strong> after the data point in time. This can cause some display irregularities at the start<br />

<strong>and</strong> stop frequencies. Use low values for the SMOOTH parameter to avoid signal distortion.<br />

By replacing the value of each point in a trace with the average of the values of a number of<br />

points centered about that point, any rapid variations in video noise or signals are smoothed<br />

into more gradual variations. It thereby performs a function similar to reducing the video<br />

b<strong>and</strong>width without the corresponding changes in sweep time. As such, it does result in a<br />

reduction of frequency resolution. Also, signal peaks are reduced with large smoothing values,<br />

<strong>and</strong> this can cause the amplitude to appear to be low.<br />

This comm<strong>and</strong> requires user memory for its execution. Memory is not permanently allocated,<br />

so the largest amount of memory is available for the functions that are used in a particular<br />

application. When the comm<strong>and</strong> is complete, memory is returned to the free user memory.<br />

Programming Comm<strong>and</strong>s 5495

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