Generate an internal pixel clock in external lock mode with 1408?

[hbchao]

Hi,

I am running a nonstandard camera with the PCI-1408 in external lock mode.  I am feeding the 1408 the video signal (BNC), HSYNC and VSYNC but I am wondering if I can somehow generate the pixel clock internally.  Currently I have a function generator connected to the card but it can only reach 10 MHz (I need the signal to be ~14MHz).  The 1408 manual claims to be able to have a "programmable pixel and line count" but I have had much trouble trying to figure this portion out.  The goal of this project is to be able to perform image automation with Labview 7.1, but I need to acquire the correct images first.

If internal generation is not possible, what would you recommend for an alternative?  A new function generator would be at least $500 and is out of the price range.

Thanks!

[David S.]

Hi hbchao -

The "programmable pixel and line count" feature of the NI 1408 is the ability to specify the height and width of an acquisition using MAX or session attributes.  The 1408 is a first-generation image acquisition device, and at the time it was developed this was an attractive feature of such a versatile device.  Of course, it is rather commonplace now, and all NI frame grabbers have this functionality.

In External Lock mode, the frame grabber must be given the VSYNC, HSYNC, and Pixel Clock signals.  Some NI frame grabbers are capable of generating a pulse train on their output, so this signal can be wired to the PCLK input of the device.  Unfortunately, this feature was not designed into the 1408.  As such, you'll have to provide an external pixel clock to this device.

The 1408 provides a RTSI interface, so the source of the pixel clock could be another NI PCI device.  If you can generate a pulse train using, say, an NI DAQ device, that signal can be routed to the 1408 using RTSI.

[hbchao]

Would the NI-USB 6009 work with this application?  I have worked with that device in the past and wouldn't mind ordering another.  Thanks again!

[GDE]

hbchao,

I'm afraid a 6009 will definitly not be able to generate a 14Mhz clock signal for you. The 6009 does not have any hardware timed output, so there is no way it can generate a clock signal anywhere near the speed you need. Even the analog input is only clocked at 48 kS/s still far slower then you would need. I don't think there is going to be any >$500 solution for what you are looking for. The products that you would want to look at is some of the Modular Instruments products.

-GDE

[hbchao]

Guys thanks for the help so far...just one more question though.  I am thinking about updating to either the 1409 or the 1410.  It seems to be possible to generate pulses with these cards, but I cannot find the specs for the frequency that is capable of being generated.  Do you know if either card can generate the 14MHz signal that I need?  Again, thanks for your help!

[David S.]

Hi hbchao -

Both of those devices can generate pulse trains of up to 25 MHz using their 50 MHz timebase.  I recommend checking to be sure your camera can receive an external P-Clock from the device, too.  If you dont' give both devices a synchronized signal, the data might be corrupted in the transfer mechanism.