Explain Cal (Explaincal) - Tektronix 11A52 Service Manual

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Explain Cal (EXPLAINCAL)
The Explain Cal diagnostic is a follow-up to selected
calco~sta~t
check diagnostics that can provide more
specific information about failures in those diagnostic routinesY:Whenever one of the selected set of calconstant
check diagnostic routines fails, information relating to oscilloscope settings in which the failure conditions will
occur are stored in a dedicated area. That storage area,which can be queried with the Explain Cal diagnostic,
contains only enough room to store the failing setting information for the last calconstant check diagnostic
executed. Only the Atten Gain, Step Gain, BWL Match, and Gain calconstant check diagnostics generate
information which may be queried with the Explain Cal diagnostic. The information retrieved by the Explain
Cal diagnostic varies depending on which calconstant check diagnostic last failed. The test returns two 16-bit
numbers in hexadecimal notation: an Address field and an Expected field. Each digit of the fields has a
particular meaning depending on which diagnostic test is being explained. Each letter (hijk, WXYZ)
corresponds to a digit in the result returned by the Explain Cal diagnostic. Unused digits in the fields are
always zero. The Actual field is not used, and is always zero. This diagnostic will always pass, as it is simply
used to retrieve information generated by other diagnostic routines.
For example, if the Gain calconstant check diagnostic failed and Explain Cal was run and returned an Address
field of 0032 and an Expected field of 0000, the results have the following meaning:
ADDRESS EXPECTED
h
j
k
w x y z
0 0 3
2 0 0 0 0
h 0 w 0
0 x 0
j 3
lOmV/div
y 0 1 mV /div
k
2
Full BW
z 0 20MHzBWL
The lowest gain error was found at 10 mV /div at the Full Bandwidth Limit setting, and the highest gain error
was found at 1 mV /div, with the 20 MHz Bandwidth Limit setting (see Table 4-3).
TABLE 4-3
Meanings of k,Z and j,Y Characters
Atten M377 Step BWL
Gain
korZ Range Gain Setting
jorY Setting
0 Xl lmV 20MHz
0 lmV
1 XlO 2mV lOOMHz 1 2mV
2 XlOO SmV Full
2
SmV
3
-
lOmV
-
3 lOmV
4
-
20mV
-
4 20mV
5
-
SOmV
-
5 SOmV
6 lOOmV
7 200mV
,
8 SOOmV
9 lV
A 2V
B
sv
11A52 Extended Service Manual
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