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648 Chapter7
Language Reference
VB Video Bandwidth
When the sweep time is <30 ms and the resolution bandwidth is ≥300
Hz, then the narrowest video bandwidth available is 300 Hz. If the
resolution bandwidth is ≤100 Hz and the span is zero, video filtering
does not occur.
Reducing the video bandwidth or increasing the number of video
averages will usually smooth the trace by about as much for the same
total measurement time. Reducing the video bandwidth to one-third or
less of the resolution bandwidth is desirable when the number of video
averages is above 25. For the case where the number of video averages
is very large, and the video bandwidth is equal to the resolution
bandwidth, internal mathematical limitations allow about 0.4 dB
overresponse to noise on the logarithmic scale. The overresponse is
negligible (less than 0.1 dB) for narrower video bandwidths.
Parameters
number integer from 1 to 3E+6.
UP or DN increments in a 1, 3, 10 sequence.
Preset State
Coupled mode, 1 MHz
Query Response
Figure 7-290 VB Query Response
Example
10 OUTPUT 718;"IP;"
20 OUTPUT 718;"CF 1.2GHZ;SP 2GHZ;"
30 INPUT "SELECT THE VIDEO BANDWIDTH, IN KHZ",B_width
40 OUTPUT 718;"VB ";B_width;"KHZ;"
50 OUTPUT 718;"VB?;"
60 ENTER 718;B_width
70 PRINT "SELECTED BANDWIDTH IS ",B_width,"HZ"
80 END
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