Can I mask some edges in a count?

[lord_ed]

Hello!

I´m trying to measure digital frequency of a signal through the attached VI.

I need to mask some pulses of the signal for count only fixed pulses.

I want to do it this way:

1.-I enter a fixed time through the front panel to one global variable.

2.-The first rising edge of the signal pauses the task over fixed time.(Counter can´t see edges)

3.-When the time is over resumes the task.(Time between first and "second" pulse)

Is that possible? If not, some suggestion?

Thank you!  

[JaimeC]

Hi,

So... what u need is only to measure pulses from time to time. That is, only make one measurement every X time when you want.

It depends about how often do u want to realize that operation. Your proposed solution is a software one, and you can do it and probably will work.

You can also insert all that program over a case structure with an input false/true that selects if the measurement can be done.

If you want to make it hardware u can connect a digital line to that selector. Other posibilities can be setting one counter as pulse generator with pause trigger before to select when to let the signal to pass...

But if you just need the measurements from time to time your solution can work ok.

[lord_ed]

Hi JaimeC.

My device must be capable to measure frequency of analog, digital, burst, AM, FM signals. For simple signals (analog freq, digital freq) I can measure frequency with the VI attached before, but with complex signals (Burst, AM,FM) I must count only fixed pulses.(PICTURE).

Is better generate other signal from the signal to measure and measure it?

Thank you.

PCI-6221.   

LabVIew 7.1

[JaimeC]

OK,

Is there any fixed length for the sinusoidal? That is.... does it take a fixed time with that signal? Or it changes?

If the time is fixed we can generate the Hold-Off signal just using one of the examples.

[lord_ed]

HI!

Well, the frequency of the burst can be any one but after it start this is the same all the time.

I don´t know how can I generate the Hold Off signal?

Regards.

[JaimeC]

Hi,

Then try to see in the examples (under Labview Help -> Find examples-> DAQ mx -> Generating Digital Pulses) and open de Generate Digital Pulse Retriggerable.

This Vi uses a counter for generating one pulse every time that a trigger arrives to the trigger parameters input pin.

This way if you connect your input signal to the trigger input. Change the CO ticks for a CO Time, that way you can configure the pulse you are going to generate to some time. Make the T on (time of your output pulse) longer than the time your signal happens. This way you will generate one pulse with that counter every burst signal arrives, and as the duration of this pulse is longer than your signal it will be only one generated.

Then, this way u will be able to generate the hold-of signal of the diagram. And you will have it in your counter output.

After that you can make the rest of the measurements with that signal.

[lord_ed]

THANK YOU.

THE SIGNAL IS PERFECT, THANKS.