
Time Interval Analyzer 7 Analog Modules
System Reference, January 2001
227
• Period/Frequency Measurement
This mode is used to measure the period or frequency of a
periodic signal.
Figure102
TrigDelayCnt
Parameters for Period/Frequency Measure-
ment
For PER or FREQ, after the trigger is detected, the TIA
counts the rising edges of the signal to start and stop the
measurement using
TrigDelayCntStart
and
TrigDe-
layCntStop
. In this case, the TIA first measures the
interval from the edge determined by
TrigDelayCnt-
Start
to the edge determined by
TrigDelayCntStop
,
then divides the interval by the number of cycles to get an
averaged period/frequency. In the above example, the
interval to be measured includes 4 (5-1) cycles of the
clock. Therefore, to get an averaged period, the measured
interval is divided by 4.
NOTE By default, 1 is set to both
TrigDelayCntStart
and
TrigDelayCntStop
. To specify one cycle of a waveform
to be measured,
TrigDelayCntStop
must be greater
than
TrigDelayCntStart
.
Trigger
Signal
1 2345TrigDelayCntStart(1) TrigDelayCntStop(5)6
The TIA measures this interval, then divides the measured
interval by 4 (5-1) to get averaged period/frequency.
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