Cit Control Menu - Tektronix 2247A Operator's Manual

Operators Familiarization.
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(CTR/TIMER PG 2) GATED FREQ
GATED PERIOD
GATED WIDTH
QA
TED EVENTS
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(TO
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CONTROL MENU)
Gated CIT Menu
CIT Control Menu
(Crr CONTROL) INTENSIFY GATE
INTENSIFY CTR
AUTO RESOL
X10 RESOL
X100 RESOL
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TRIG TIMEOUT
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CIT Control Menu
(Descriptions are applicable for timer control menu also; however, INTEN-
SIFY GATE and INTENSIFY CTR are not available In that menu.)
The CIT control menu contains measurement modifier functions that can
Increase the versatility of CIT measurements. The first two menu items are
applicable only to gated CIT measurements. Only one of these two items
can be selected at a time.
INTENSIFY GATE-When a CIT measurement Is first called up, this
Item Is selected by def a ult. When selected, an Intensified zone will
appear on the A sweep display of the channel that the CIT Is
measuring. The position and width of this Intensified zone can be
altered In the same manner as In gated Volts measurements. The CIT
will only measure trigger edges that occur somewhere Inside this zone .
INTENSIFY CTR-When this Is selected, the gate signal generated by
the CIT hardware will control the position and width of the Intensified
zone, thus providing an unambiguous display of what the CIT is actually
measuring.
The next three menu Items allow the selection of a resolution magnifier.
Only one of the three may be selected at a time. All CIT measurements
except FREQ RA TIO and TOT ALIZE can utilize resolution magnifiers. A CIT
measurement must have been previously selected before a resolution mag-
nifier selection will have any effect.
AUTO RESOL-Thls Is the default setting when a CIT measurement Is
first called up. The CIT uses a fixed measurement time interval
( approximately 320 milliseconds, or 1 period of the trigger signal,
whichever Is larger, for single channel measurements; approximately
600 milliseconds for dual channel measurements) . The resolution of
the measurement is then calculated, and as many fully-resolved digits
as possible are displayed.
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Operators Familiarization
X1
o
RESOL-When selected, the CIT will make one trial measurement
using the fixed measurement time Interval, and calculate and dlspl~y
as many fully-resolved digits as possible. Based on the results of this
measurement, It Is determined whether or not another digit of reso-
lution Is possible. It Is poss Ible if:
1 . The number of digits displayed after the trial measurement Is at
least 1 less than the maximum number of digits displayable for that
measurement, and:
2. If PERIOD measurement, the units of the least-significant digit
(LSD) are larger than 100 attoseconds ( 100 X 10-
10
sec), or if any
other time-Interval measurement, the units of the LSD are larger than
1 plcosscond ( 10-
12
sec).
If It Is not possible, the message "NOT POSSIBLE--->" Is displayed to
the left of the X10 RESOL menu label for approximately one second,
then the X1
O
RESOL label is deselected and the AUTO RESOL label is
selected (underlined), and the measurement proceeds In auto reso-
lution mode. ·
If the selected mode Is po'ssible, the measurement time Interval
required to get one more -fully-resolved digit Is calculated. If this time Is
greater thari 5 seconds, the message "MEASMT TIME XXXXs" Is
displayed to the left ·of the X10 RESOL label, where XXXX Is this
measurement time Interval in seconds. If t~is time Interval Is greater -
than 9999 seconds, the message "MEASMT TIME >9999s" is displayed
Instead. The measurement then proceeds using this ~ew measurement
time Interval .
~ J
X100 RESOL-When selected, the CIT will make onf trial measure-
ment using the fixed measurement time interval, and c~lculate and
display as many fully-resolved digits as possible. 'Based on the results
of this measurement, It Is determined whether or not two more digits
of resolutlon are possible. It Is possible if:
1 . The number of digits displayed after the trial measurement is at
least 2 less than the maximum number of d)glts displayable for that
measurement, and:
2. If PERIOD measurement, the units of ' the least-significant digit
(LSD) are larger than 1 femtosecond ( 1 X 1
o-
15
sec) , or If any other
time-Interval measurement, the units of the LSD are larger than 10
picoseconds ( 1 O X 10 -
12
sec) .
If It Is not possible, the message "NOT POSSIBLE
~
" Is displayed
to the left of the X100 RESOL menu label for approximately one
second, then the X100 RE SOL label Is deselected and the X10 RE SOL
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