Perform "Buffered semi period measurement" and read the digital line status at the same time. Possible??

[Tomm]

Hello,
I want to perform an buffered semi-period measurement.
However, additionally to the measured times I want to
display the logical line status (I want to see the rising and falling edges of several lines)
The fastest signal lasts approx. 1ms.

Is it possible to do these two things
(perform the buffered semi-period measurement and display the edges) simultaneously?

Another problem is that I need an accurate timebase for the xy-graph to display the edges?
How can I produce one? Or where can I obtain one.
Because I think the tick count is too inaccurate at times of 1ms. Or I am at fault?

Any suggestions?

Regards Tomm

[RIO-Todd]

Tomm,

Counters really aren't conducive to dislaying TTL signals or pulse trains. The data we get from the counter is pretty much the count stored in the count register and with that we can calculate frequency, period, etc. of TTL signals but you really can't display the data received from the counter.

One thing you could do is use an analog input to acquire and present the TTL signal. If you have a National Instruments multifunction data acquisition device, you probably have access to analog inputs. You could input the TTL signal into a counter and an analog input and use the counter to give you precise numeric period readings and then plot the array of voltages received from the analog input on a chart/graph. Just a suggestion.

Regards,

Todd D.
Nat
ional Instruments
Applications Engineer

[Tomm]

Hello Todd,

thanks for your fast answer. I have the NI 6602 card. So I could read the digital line and count the edges simultaneously.

But where can I obtain an accurate timebase for the chart/graph?
I tried to use the Tick Count but on signals which lasts only 1ms it seems to be inaccurate.

Any hints or tips?

Regards Tomm