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Yes, the problem is that to restore a pulse you first need to see it's actually missing, so you obviously will have a slight delay. IMO the controller should precisely determine the interval between 2 pulses with the provided video source, and as soon as it doesn't see a pulse after that interval has passed it should send one.

But that's only one part of the problem. Interference will obviously make you lose syncs, but it will as well "insert" extra unwanted ones. As the noise is always pretty random, there's no reason why it wouldn't send the level at a sync's one from time to time. There we're in trouble again.

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True, but that again goes back to the question of how sensistive these recorders are to sync timing. Will they notice a 1us delay in the start of a sync pulse?

I think that this is worth a try, anything has to be better than seconds of useless blue-screen.

To see if this idea holds water I'll do a few tests. One would be to capture a few frames of video into a high-speed Arb and replay them in a loop. This will allow the sync timing to be tweaked to determine the sensitivity of the recorders to it.

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and what about this idea:

create a blank page video generator sync it with the received signal (as frequently as needed) and use RSSI signal from your receiver to tell your circuit whether to use original video signal or blank page video signal instead? That would be probalbly a little bit oversensitive than detecting actual loss of sync condition, but you may even add a threshold knob to control how sensitive it is and how much garbage you will receive.

Edited by mieczotronix
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-AT-mieczotronix: I thought of something similar, and the problem is that this local sync generator must be exactly in sync with the original video signal, and keep free running when there's no signal to lock to, or even worse when the signal that comes in is total crud and might mess up the locking circuit.

If these problems are overcome then this is a great solution.

(Another option would be to sample the video signal and put it out again. So after the AD/DA conversion a new generated video signal is there, and stable. But would be again HUGE :-)

Just my 2 cents,

Hartwig

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If it's not for the fussy PVR you might have, it doesn't have to be in exact sync. Either you will sync the blank page generator every couple of seconds or you do without it at all. You just loose less of 1 second of video while your LCD resyncs from one sync to another. I've just built a simple video switch to switch between two cameras without any syncing and my cavalary PVR copes with that.

The problem is that you would have to transmit telemetry data through completely different downlink (433 Mhz or sth like that) than video downlink. As when you loose video signal you would loose whats transmitted in audio channel as well.

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what about a turn OSD on/off via a servo channel ?

it is simple and helps alot on everything,

the onboard computer will always have 100% access to sensors,

so nothing will be lost in the capacity calculations and whatever smart things you have.

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Hi

I have download File and schematics from DLZ's webpage and have build and test the OSD with not working results.

I have connect my EM-406 GPS and I expected to see the raw NMEA data in the screen, but nothing it's in the screen only the video.

Have anybody have success with this OSD?

What are the AVR fuses? I thing I don't have set fuses right.

Thanks

Eladio

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Hi calevepas and eladiomf (and others)

the OSD I have on my web site is a beta version,

it is unducumented and unsupported and not designed for people to reconstruct,

tons of bugs and trouble in the old test firmware versions I have online,

since it is all old stuff I made for fun.

The real super OSD solution have been made and have now tons of usefull features, it can be purchased via

http://www.intelligentflight.com.au/solutions.aspx quite soon,

please write to Mark Harris and get on the first-purchaser list,

I know he work day and night to be able to help you out soon.

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C'mon. It's not that bad. The beta version does work actually pretty well. I have been testing it for a while on my workbench. I've converted it to SPI and it does work, yet still needs some tweaks. (You have to be careful with sending data to it, so that data is not arriving too fast and bytes are not lost.)

BTW It's a rework of OSD AVR (NTSC), which is available at avrfreaks.

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C'mon. It's not that bad. The beta version does work actually pretty well. I have been testing it for a while on my workbench. I've converted it to SPI and it does work, yet still needs some tweaks. (You have to be careful with sending data to it, so that data is not arriving too fast and bytes are not lost.)

BTW It's a rework of OSD AVR (NTSC), which is available at avrfreaks.

Hi mieczotronix

Please can you (or anybody) tell me the fuse settings that I have to use to program the ATmega88 with the beta firmware that it's in DZL webpage.

I don't want it to fly FPV, it's for another aplication. I just want send serial data at 4800baud 8N1 and display it in a TV set.

I would like to known settings for:

CKSEL

SUT

CKOUT

CKDIV

BODLEVEL

EESAVE

SPIEN

RSTDISBL

BOOTSZ

Thanks in advance

Eladio

Edited by eladiomf
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oh I did not see this post for a long time,

the page is updated now with latest information.

Oh Thomas.. haven't seen you much lately... finally broke free from the dungeon huh? :D I thought someone locked you up in a secret lab and made you work day and night :D

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> thought someone locked you up in a secret lab and made you work day and night

they did.. now finally the OSD project is done and I can get out again.

pyha but it was a lot of fun and many cool things learned.

I am very proud of the result and performance of it.

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