HP 8591C, Руководство пользователя, Страница: 294 / 373

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Test Descriptions
In-Channel Frequency Response Test Description
R E F
0 4 5 8 N O V 2 3 . 1 9 9 3
C H A N N E L 4 M K R 7 0 . 8 7 5
L O G
4
W A S t
S C
M A R K E R 1
M A R K E R 2
M O R E
I
C E N T E R 6 9 . 0 0 0 S P A N 6 . 0 0 0
3 0 0 3 6 . 9 0
Figure g-17. Multi-Burst Response
Single line Testing
Single line vits testing can be performed on multiburst, sin X/X, Philips ghost
canceling reference (GCR), or NTC-7 combination.
GCR provides the best results because it has the most signal level and it is a
swept frequency over the range of interest.
The sin X/X is also a continuous signal in the frequency domain when using
100 resolution bandwidth for detection. Its lower energy content requires
higher signal levels or averaging to be used to get equivalent results to the
GCR.
Multiburst can be used but it does not provide a continuous display across the
channel as does GCR and sin X/X.
The NTC-7 combination signal is the least ideal. It would be useful for
relative measurements. The frequency burst’s lengths are not equal and
too short in duration for the 300
resolution bandwidth to capture them
accurately. Some modified NTC 7 combination test signals have near equal
pulse widths and are more suitable for this test.
Refer to “In-channel frequency response test” in Chapter 2 for illustrations of
the various test signals.
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