Language Reference

SMOOTH

70

OUTPUT 723;"SMOOTH TRA,NN;";

Average each point of trace A with points NN/2 either

 

 

 

side of it.

80

OUTPUT 723;"CLRDSP;";

Clear graphics from memory .

90

OUTPUT 723;"PA 100,700;TEXT$Smoothing over $;";

Write text.

100

OUTPUT 723;"DSPLY NN,4,1;";

Write the value of NN on the spectrum-analyzer

 

 

 

display .

110

OUTPUT 723;"PA 740,700;TEXT$points$;";

 

120

OUTPUT 723;"WAIT 2S;";

Wait 2 seconds .

130

OUTPUT 723;"UNTIL NN,EQ,100;";

End repeat loop when each trace point has been

 

 

 

averaged with 50 points on its left, and 50 points

 

 

 

on its right side .

140

OUTPUT 723;"WAIT 1S;"

Wait 1 second.

150

OUTPUT 723;"IP;"

Instrument preset.

Description The SMOOTH command smooths the amplitude level of a trace. The amplitude values of the trace are modi￿ed according to the number of

points speci￿ed for the running average. Each point value is replaced with the average of the values (in measurement units) of the given number of points centered around the point. The SMOOTH function performs a spatial, video averaging, in comparison to the temporal averaging achieved by the video-averaging command, VAVG. By replacing the value of each point in

a trace with the average value of neighboring points, high-wavelength noise or signals are attenuated without a corresponding e￿ect on low wavelength signals. Thus, the function of SMOOTH resembles narrowing of the video-bandwidth ￿lter without the corresponding increase in sweep time. SMOOTH does reduce wavelength resolution.

Use SMOOTH as you would use video ￿ltering to view low level signals near the noise ￿oor. If the number of points parameter is an even number, then number of points is increased by one. If number of points is greater than the length of the source, then the size of the source is used for the smoothing operation (unless the size of the source is even, in which case the size of the source less 1 is used). The SMOOTH command requires su￿cient internal memory to operate. Once the command is completed, any memory required by the SMOOTH function is released for other operations.

See Also VAVG

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