highest output frequency with NI 6602

[Mario Behn]

Hello,

with the NI 6602 and the timebase of 80 Mhz,
what is the highest frequency, which could be given out?

I got 20 Mhz (well bad signal shape, it's the capacity).

Is 40 Mhz programmable, and with some more attention to the envirement, with
better conditions?

Thanks

Mario


--

Mario Behn
345 Lincoln Avenue Apt. 1025
Amherst, MA, USA

Tel.: +1-413-546-6656

[Filipe A.]

Mario;

The maximum frequency you can generate with your 6602 depends on which counter output mode you are using. Two modes are available: "pulse" and "toggle." The default mode is "toggle." When using this mode, you explicitly specify a duration (in timebase counts) for the delay and width of each cycle in the pulse train. In LabVIEW, these values are set using "pulse spec 1" and "pulse spec 2" in the Set Counter Attribute VI. In the NI-DAQ API for C or Visual Basic, they set by parameters ND_COUNT_1 and ND_COUNT_2 of the GPCTR_Change_Parameter function. After each Pulse Spec, the counter output changes (toggles) states. Acceptable values range from 2 to (2^32)-1. This means the fastest possible pulse train (2 for each value) will have a frequency equal to o
ne fourth of the timebase. Since the board's quickest timebase is 80 MHz, you can generate a 20 MHz pulse train in "toggle" mode.

To set the counter to "pulse" mode in LabVIEW, you should call the Set Counter Attribute VI and change the "output mode" parameter. This is accomplished in the NI-DAQ API by using GPCTR_Change_Parameter to set ND_OUTPUT_MODE to ND_PULSE. In Pulse Mode, the counter outputs a pulse at each pulse spec (instead of changing states). This effectively doubles the output frequency. Using the 80 MHz timebase, you can produce a 50% duty cycle output with a frequency of 40 MHz.

Regards
Filipe A.
Applications Engineer
National Instruments

[Mario Behn]

Filipe,

i changed the mode...

.... and i got 40 Mhz!

Thanks

Mario B.

--

Mario Behn
345 Lincoln Avenue Apt. 1025
Amherst, MA, USA

Tel.: +1-413-546-6656
"Filipe A." schrieb im Newsbeitrag
news:50650000000500000084C40000-1042324653000@exchange.ni.com...
> Mario;
>
> The maximum frequency you can generate with your 6602 depends on which
> counter output mode you are using. Two modes are available: "pulse"
> and "toggle." The default mode is "toggle." When using this mode, you
> explicitly specify a duration (in timebase counts) for the delay and
> width of each cycle in the pulse train. In LabVIEW, these values are
> set using "pulse spec 1" and "pulse spec 2" in the Set Counter
> Attribute VI. In the NI-DAQ API for C or Visual Basic, the
y set by
> parameters ND_COUNT_1 and ND_COUNT_2 of the GPCTR_Change_Parameter
> function. After each Pulse Spec, the counter output changes (toggles)
> states. Acceptable values range from 2 to (2^32)-1. This means the
> fastest possible pulse train (2 for each value) will have a frequency
> equal to one fourth of the timebase. Since the board's quickest
> timebase is 80 MHz, you can generate a 20 MHz pulse train in "toggle"
> mode.
>
> To set the counter to "pulse" mode in LabVIEW, you should call the Set
> Counter Attribute VI and change the "output mode" parameter. This is
> accomplished in the NI-DAQ API by using GPCTR_Change_Parameter to set
> ND_OUTPUT_MODE to ND_PULSE. In Pulse Mode, the counter outputs a pulse
> at each pulse spec (instead of changing states). This effectively
> doubles the output frequency. Using the 80 MHz timebase, you can
> produce a 50% duty cycle output with a frequency of 40 MHz.
>
> Regards
> Filipe A.
> Applications Engineer
> National Instruments