NTSC Arbitrary Sequence

[Elizabeth_K.]

Hi Kevin,

To make sure we're on the same page, you were able to start using the VideoMASTER Analog Generator software and that is what you would like to use to create the NTSC signal? I would suggest starting with this tutorial if you haven't seen it already - Getting Started with NI VideoMASTER for Analog Generation. 

Are you using LabVIEW to program the 5421? If so, you can start from the Fgen Create From File (I16) example that is in LabVIEW's example finder.

Thanks,

Elizabeth

[JerryAL]

Hi Kevin,

In terms of NTSC waveform size for the NI 5421 AWG.  A NTSC spec waveform will be 2.6712 Mbytes.

A NTSC repeats its timing every two video frames.  The VideoMaster software creates NTSC waveforms using two frames of video data.  This works out as follows  2 frames x 525 lines per frame x 1272 samples per line x 2 bytes per sample = 2.6712 Mbytes.  The sample rate of the data is 20.013986 MSps.

The data type of the file is binary, an array of I16 binary samples. The extension of the file is .bin I think.

I’m not sure what a .vbf file is.

The NI 5412 will generate a video waveform, but not to NTSC spec.  The bandwidth is too low.  IE, in the video signal, there is a 3.58 color burst signal, while the bandwidth of the NI 5412is relatively flat at this point, even with the module’s spec, the signal is attenuated a bit which makes a noticeable effect on the colors.  At least if you know what you are looking for.  The NI 5412 has a wider bandwidth, and generates the signal better.  Generation is improved a little more on the NI 5421, but I’m not sure how we’ll work around it on LabVIEW RT, but the VideoMaster SW uses a special cal constant saved to the module’s cal coefficients (NI 5421 only) to filter (pre-distort) the data just a bit to make the video signal perfect at the output.  You can still download the binary file on LabVIEW RT using normal niFGen software, you may not even notice the difference. 

Jerry

[kevin.key]

Ok, thanks for all the info.

[ckoefoed]

.vbf = Video Binary Files only have relevance to VMS/VideoMASTER Analyzer and not the Generator. The Analyzer is capable of saving acquired waveforms in a .vbf file. That file can be loaded into the Analyzer for off-line analysis.

Christian Koefoed, PSE, NI Multimedia products