DaveABQ
Albuquerque, NM
I can answer Brian's answer a little more, he asked me to provide more information. I provided Brian the DVR for testing, I had some on ebay but sold them all and waiting for more to come in. I went round and round with the Chinese on finding a certain DVR that has many features. As Brian stated, all these DVR's are Chinese, well kind of, one major one, Lawmate, is made in Taiwan. I've had numerous emails, Skype'd with some (that was interesting), spoke to a few on the phone, etc.
There were a few things I was trying to do, it all started with trying to render the horizontal lines out of the video signal of the Armasight thermals. The signals from all the thermals are analog, all these recorders are D1 analog. The upper end Lawmate's render out the video horizontal lines, the lower end ones do not. The upper end ones that do, the PV500EVO2 and the PV-1000 Touch do no have built in microphones. I built cables that put a microphone integral with the cable, Todd has one now that he is testing out.
One thing you will notice with all thermal scopes and DVR combinations is that many times in the video recording that they lose the inner horizontal crosshair. I worked with an engineer in China to help solve this issue. They first provided me with one DVR but it would not consistently show the crosshair, then they gave me a High Definition DVR to try that had a bunch of features, including an HD camera that would do 1920x1080. We finally got to the configuration, whatever they did, that would always show the crosshairs, always. They had my troubleshooting data, video's, etc.
I then built a filter to fix the horizontal lines, which are a separate issue from the crosshairs, but both seem to be somewhat related. I spent a lot of time trying to come up with a filter that would work, first working impedance matching between the two, then trying filters for noise, grounding issues, video stabilization, etc. I finally came up with a design that worked, got with the Chinese and had them make the filters, I then build the cables with the filters. I did have fun looking at video signals with my oscilloscope, this is with an without filtering, I let you decide which is which lol if you know something about back porch, front porch, sync tip, fields, etc. Took me awhile to see what was going on, syncing on video isn't easy, looking at the different fields is also tricky:
Anyways, so a combination of the DVR I am getting directly from the Chinese and my cable, puts out a clear display, no more horizontal line distortion and the crosshairs are always there.
Video testing. This was a day with snow here in Albuquerque:
edit, Brian is also using my cable with filter. I also built many recently for other members on the forum and elsewhere.
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