NBTV Camera Question

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Postby gary » Sat Jun 16, 2012 4:39 pm

That looks fine harry, but I have just thought of something. Is your sync detector in the right position? Obviously, as the first (or last) aperture is passing the light source THAT is when the detector should be pointed at that missing sync segment. In this case it would be right next to your light source but from memory I think you have it mounted elsewhere - the answer to that is just move that bit of white paper to whatever segment is in front of the detector as the end of the last line passes the light source. Ideally the front edge of the missing sync (that is where the leading edge would be if it wasn't missing (gawd)) is where the detector should be. (This is ridiculously difficult to describe).

One way I can think of setting that up is to just have your light source on and a white piece of paper in the "focus" spot. turn the disk until the first raster line just comes on to (or the last goes off) the white paper. Hold the disk at that location and replace the corresponding encoder segment with that bit of paper.

Sheesh - if you can follow that you're a better man than I Gunga Din...
;-)

Edit: and by "that bit of paper" I mean the bit of paper shown in Harry's photo above NOT the bit of paper the raster was shown on, dear me...
Well YOU try explaining it... LOL.
Last edited by gary on Sat Jun 16, 2012 5:25 pm, edited 1 time in total.
gary
 

Postby Harry Dalek » Sat Jun 16, 2012 5:12 pm

gary wrote:That looks fine harry, but I have just thought of something. Is your sync detector in the right position? Obviously, as the first (or last) aperture is passing the light source THAT is when the detector should be pointed at that missing sync segment. In this case it would be right next to your light source but from memory I think you have it mounted elsewhere - the answer to that is just move that bit of white paper to whatever segment is in front of the detector as the end of the last line passes the light source. Ideally the front edge of the missing sync (that is where the leading edge would be if it wasn't missing (gawd)) is where the detector should be. (This is ridiculously difficult to describe).



OH !!!!!! Yes move the missing sync i can do that i understand now that makes sense ,i will work it out today ..have to go out later might have time to work it out
One way I can think of setting that up is to just have your light source on and a white piece of paper in the "focus" spot. turn the disk until the first raster line just comes on to (or the last goes off) the white paper. Hold the disk at that location and replace the corresponding encoder segment with that bit of paper.


Yes thats a good procedure ,i can see what you mean now by have the encoder on something to rotate some that needs adjusting at least once .

Sheesh - if you can follow that you're a better man than I Gunga Din...
;-)


I think you have to have an encoder to know what you mean and i sure do :wink:
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Postby Harry Dalek » Sun Jun 17, 2012 2:06 am

Heres the monkey test with the change to the encoder which would mainly be of interest to gary but i have posted it here as its a little bit better than the last very much so towards the latter part.
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Postby gary » Sun Jun 17, 2012 10:49 am

Yes, Harry that's fixed it, well done.

That worked so well I think it is showing that one (at least) of your apertures is obstructed, possibly by dirt etc. It might be worth passing a needle through them to clean them up a little.
gary
 

Postby Harry Dalek » Sun Jun 17, 2012 12:55 pm

gary wrote:Yes, Harry that's fixed it, well done.

That worked so well I think it is showing that one (at least) of your apertures is obstructed, possibly by dirt etc. It might be worth passing a needle through them to clean them up a little.




Yes a bit of handling gary i notice it i tend to block some of the holes .

I am glad that worked for the encoder and its on the forum i can review this if i forget about it in the future .

There is not to much on encoder problems on the forum so thats a good one thats logged.

I am going to try to start on the motor control today ...i have to put another multi cable mainly for getting the encoder pulse to my 4046 PLL

And i haven't really bothered with the video board for the luxeon since i made it but i have been thinking of another use multi use feeding the video from the video mixer to it i was thinking it might adjust the video levels better than the just using the mixer out to the pc since it has brightness contrast and gamma control...looks good control for the luxeon so i suppose right from the last ic to the pc might have the same effect ...

I am not sure i have control correct for those levels the sync mixing and video mixing levels sort of control the video output how much more i can correct it i need to look into ...need a grey scale card in a few levels to see what it can do .
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Postby gary » Sun Jun 17, 2012 3:57 pm

There is a one good argument for getting the monitor part of this project going Harry, in that it will be DC coupled so you won't get the unavoidable sag associated with the AC coupling of PC recording.

I notice on the your last offering there is quite a bit of sag causing picture-on-sync syndrome.


edit: you could, of course, pipe it into one of your previously constructed monitors too.
gary
 

Postby Harry Dalek » Sun Jun 17, 2012 5:46 pm

gary wrote:There is a one good argument for getting the monitor part of this project going Harry, in that it will be DC coupled so you won't get the unavoidable sag associated with the AC coupling of PC recording.


I will look into trying to improve the video signal part next ,todays a big day and will improve the video in another way i have now got it on crystal motor control !
And it gets to correct speed very fast no over hunting for correct speed its pretty good..have not used the 4046 pll in many years nice to have a switch on and work right off the bat .
The 400 hz is off the lm311 encoder circuit now thats what i like to see!

I put in a switch so i can switch between PWM manual and crystal controlit was there so why not . :)

I notice on the your last offering there is quite a bit of sag causing picture-on-sync syndrome.


Lets see what happens on the next test ..i hope with the speed no longer an adjustment it will be better ..


e
dit: you could, of course, pipe it into one of your previously constructed monitors too.


Yes true...i have never done that ! reason i have been pushing for a correct nbtv signal and be able to be played on any thing ,would now be test gear /
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The electromagnetic spectrum has no theoretical limit at either end. If all the mass/energy in the Universe is considered a 'limit', then that would be the only real theoretical limit to the maximum frequency attainable.
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Postby gary » Sun Jun 17, 2012 6:44 pm

Just to be clear Harry, the sag in the video is due solely to the AC coupling with the PC sound card and has nothing to do with your circuitry - you have widened the sync pulses which helps but that is about as much as you can do.

Of course, good speed control has advantages in other areas.

I suppose I have add that the sag leading to picture-on-sync is the main reason I use and promote sync on the right channel.

None-the-less what you are doing is perfectly viable - just keep in mind that there will be some picture content where the sag is so bad it may lead to loss of sync or poor greyscale no matter what you do.
gary
 

Postby Harry Dalek » Sun Jun 17, 2012 7:10 pm

Hi gary


gary wrote:Just to be clear Harry, the sag in the video is due solely to the AC coupling with the PC sound card and has nothing to do with your circuitry - you have widened the sync pulses which helps but that is about as much as you can do.


Oh theres another thing when i view and record both programs slow down the 300mhz pentium there a few second delay in what is filmed to what is viewed perhaps this is a record thing to if i use both programs at the same time .
Well i am glad i am doing the sync pulse part right .


Of course, good speed control has advantages in other areas.
I suppose I have add that the sag leading to picture-on-sync is the main reason I use and promote sync on the right channel.


I suppose theres no reason i could not do that to as well just connect the unsynced video to a plug out and sync just it does the mix as well via another plug....i just wanted to do the mix as a challenge you got me interested .


None-the-less what you are doing is perfectly viable - just keep in mind that there will be some picture content where the sag is so bad it may lead to loss of sync or poor greyscale no matter what you do.



OK perhaps i am being to fussy anyway i will see what happens if i can do another test tonight ,tell you it will be so much easier not having to worry about that motor speed..
The electromagnetic spectrum has no theoretical limit at either end. If all the mass/energy in the Universe is considered a 'limit', then that would be the only real theoretical limit to the maximum frequency attainable.
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Postby gary » Sun Jun 17, 2012 7:36 pm

Oh theres another thing when i view and record both programs slow down the 300mhz pentium there a few second delay in what is filmed to what is viewed perhaps this is a record thing to if i use both programs at the same time .


Hmmm, there must needs be some delay but not of the order of seconds - very strange.

Harry I always meant to add recording to TBP - as you can see there is a disabled "NBTV wave file" option in "destination" menu " for TBP, and that would have eliminated any delay between what-you-see and what-you-get. Alas, as I have lost my source code for alpha TBP it will now never eventuate.

tell you it will be so much easier not having to worry about that motor speed..


Indeed! :-)
gary
 

Postby Harry Dalek » Sun Jun 17, 2012 8:42 pm

Hmmm, there must needs be some delay but not of the order of seconds - very strange.


Yes a few seconds at least 3 to 4 ! with the tiny viewer,its fine on its own its live but soon as i bring up the recording program things slow down on the monitor screen...i would say its lack of memory on this old thing.
I can say wave my hand wait and then it comes up also its televised slowish.
I was thinking it must cause a problem on the recording side as well .

Harry I always meant to add recording to TBP - as you can see there is a disabled "NBTV wave file" option in "destination" menu " for TBP, and that would have eliminated any delay between what-you-see and what-you-get. Alas, as I have lost my source code for alpha TBP it will now never eventuate.


Yes it would of come in handy ,i could look for a tinier recoding program but i sort of like this one.i will have a look if this lap top has a slot for more memory i should have some spare memory for it if so .

tell you it will be so much easier not having to worry about that motor speed..


Indeed! :-)
[/quote]


I hope i have time very keen to see a test .
The electromagnetic spectrum has no theoretical limit at either end. If all the mass/energy in the Universe is considered a 'limit', then that would be the only real theoretical limit to the maximum frequency attainable.
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Postby Harry Dalek » Mon Jun 18, 2012 12:45 am

Here are a few more tests U1 is a donkey toy similar to the monkey
U7 is me at times i am in focus i am going to have to work out the correct distance for a person head shot ,it might be the limits of this camera..with the light levels..so i really need work out the distances aways from the camera .

Gary looking at a bit of the missing picture when viewing on big screen do you think that is due to the width of the sync pulse still being to narrow ?

any way i can see its a bit better and the clock is a big help !
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The electromagnetic spectrum has no theoretical limit at either end. If all the mass/energy in the Universe is considered a 'limit', then that would be the only real theoretical limit to the maximum frequency attainable.
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Postby gary » Mon Jun 18, 2012 2:31 pm

harry dalek wrote:Gary looking at a bit of the missing picture when viewing on big screen do you think that is due to the width of the sync pulse still being to narrow ?


No, your sync is fine - if anything a little too wide (.29 mS). No, any picture problems will be related to the fact that your speed is still varying quite wildly from -12% to +7%
gary
 

Postby Harry Dalek » Mon Jun 18, 2012 3:45 pm

gary wrote:
harry dalek wrote:Gary looking at a bit of the missing picture when viewing on big screen do you think that is due to the width of the sync pulse still being to narrow ?


No, your sync is fine - if anything a little too wide (.29 mS). No, any picture problems will be related to the fact that your speed is still varying quite wildly from -12% to +7%


OH i didn't bother with the scope when testing last night this is surprising..mmmm

I wonder if running it all together has changed something voltage`drop perhaps ...:roll:

Wheres my my multimeter and screwdriver :?
The electromagnetic spectrum has no theoretical limit at either end. If all the mass/energy in the Universe is considered a 'limit', then that would be the only real theoretical limit to the maximum frequency attainable.
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Postby Harry Dalek » Mon Jun 18, 2012 10:52 pm

I am putting this test sync recording on just to check hope gary sees it its pretty steady at 396 397HZ i expect the mechanical part does delay any 100% steady speed ...... doing process control charts at BHP many years ago i did learn nothing is steady every thing moves in waves .

Gary if you see this i am putting it up to check my scope frequency meter once and for all its showing this speed now pretty steady from our pms in the past the freq seemed to be off on my scope so this is a check tonight other wise i will readjust it to 400hz...bit i am thinking the scope is off a few HZ.
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The electromagnetic spectrum has no theoretical limit at either end. If all the mass/energy in the Universe is considered a 'limit', then that would be the only real theoretical limit to the maximum frequency attainable.
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Harry Dalek
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