Chapter 7
Counters
©
National Instruments
7-13
X Series User Manual
Fig
u
re 7-11 shows an example of an implicit b
u
ffered semi-period
meas
u
rement.
Figure 7-11.
Implicit Buffered Semi-Period Measurement
For information abo
u
t connecting co
u
nter signals, refer to the
Default
Counter/Timer Pinouts
section.
Frequency Measurement
Yo
u
can
u
se the co
u
nters to meas
u
re freq
u
ency in several different ways.
Refer to the following sections for information abo
u
t X Series freq
u
ency
meas
u
rement options:
•
Low Frequency with One Counter
•
High Frequency with Two Counters
•
Large Range of Frequencies with Two Counters
•
Sample Clocked Buffered Frequency Measurement
•
Hardware-Timed Single Point Frequency Measurement
Low Frequency with One Counter
For low freq
u
ency meas
u
rements with one co
u
nter, yo
u
meas
u
re one
period of yo
u
r signal
u
sing a known timebase.
Yo
u
can ro
u
te the signal to meas
u
re (
fx
) to the Gate of a co
u
nter. Yo
u
can
ro
u
te a known timebase (
fk
) to the So
u
rce of the co
u
nter. The known
timebase can be an onboard timebase, s
u
ch as 100 MHz Timebase, 20 MHz
Timebase, or 100 kHz Timebase, or any other signal with a known rate.
1
2
3
1
3
3
S
o
u
rce
G
a
te
Co
u
nter V
a
l
u
e
B
u
ffer
1
3
2
2
1 1
1
3
1
2
0
Co
u
nter
Armed
S
t
a
rting
Edge
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