I'm using a NI PXI-6229 to measure a 32.768kHz RTC ref clock.
I'm setup in MAX with a task using the largerange2 counter frequency measurement, as I need a very precise measurement.
Every say, 1 in 30 measurements comes back wildly out of value compared to the baseline.
ie. 32950.1287968 Hz with a divisor of 181.
When it fails it always is 32950.XXXX when the divisor is 181. Otherwise seems very accurate.
This value is 181/180 * the value.
I figure that one extra trigger in the sample pre divisor might be the problem, but scoping the signal I don't see any glitches.
Is there a way to filter higher frequencies.
Any ideas?