Mirror Camera project

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Re: Mirror Camera project

Postby gary » Thu Jul 17, 2014 9:09 pm

Your tests look normal considering what you are putting into the system (as far as I can tell) - obviously yur gain is too high and you need to match your sync pulse depth to your video signal by making it 1/3 the depth of white - the pulse width in the first test looks the most correct. keep in mind the effects of AC coupling.
Attachments
sync via sync video mixer.jpg
sync via sync video mixer.jpg (78.9 KiB) Viewed 12417 times
sync via sync video mixe adjust syncr.jpg
sync via sync video mixe adjust syncr.jpg (77.84 KiB) Viewed 12417 times
sync start up light on light sensor adjusting sync pulse width.jpg
sync start up light on light sensor adjusting sync pulse width.jpg (81.51 KiB) Viewed 12417 times
gary
 

Re: Mirror Camera project

Postby gary » Thu Jul 17, 2014 9:17 pm

Oh and Harry please, please, PLEASE try and change only ONE thing at once per test I beg you - for instance when you change your pulse width have only one pulse width per test not various widths through the wave form which makes the wave form just a big mess and I can't show you the detail like I have in the first test.
gary
 

Re: Mirror Camera project

Postby Harry Dalek » Fri Jul 18, 2014 11:53 am

gary wrote:Oh and Harry please, please, PLEASE try and change only ONE thing at once per test I beg you - for instance when you change your pulse width have only one pulse width per test not various widths through the wave form which makes the wave form just a big mess and I can't show you the detail like I have in the first test.


Thanks for the help there Gary i knew that one was no a good test just was trying to show how it became more sensitive to light when i increased the pulse width of the line pulse ,i didn't under stand that .


I will take note and not multi adjust and test record . :wink:
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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Re: Mirror Camera project

Postby gary » Fri Jul 18, 2014 11:07 pm

Harry, I just want to make it perfectly clear that it is NOT becoming more sensitive to light, it is just that widening the pulse is making the average of the signal more positive.
gary
 

Re: Mirror Camera project

Postby Harry Dalek » Sat Jul 19, 2014 11:31 am

gary wrote:Harry, I just want to make it perfectly clear that it is NOT becoming more sensitive to light, it is just that widening the pulse is making the average of the signal more positive.


Ok Gary that makes more sense and gives me a reason for the effect i was seeing on pulse width adjustment.

I will be looking into the sync video mixer today as i didn't take into account the line pulses amplitude would effect it ,its a thing over looked ! live and learn. :roll:
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Re: Mirror Camera project

Postby Harry Dalek » Sat Jul 19, 2014 4:35 pm

OK i will try and look into the club handbook sync video mixer here and my version of it look at what i have over looked .

First up

I am not using PD1 LED 1 R6 and R8.

Using the opto swich and LM311 feeding the 4528 monostable for pulse width control.

Now having another look at problems i have overlooked

Pin 7 the line pulse is feeding Q1 base but i need some resistance between the 2 or the sync pulse over rides the video signal as Gary pointed out.

Need to see the range of this for it mix correctly.

Need to also lower the pulses amplitude .

I also found the video sync mixer has a problem working off 12 volts i am not sure if it is because i am not using PD1 LED 1 R6 and R8 part of the circuit.

The range it works on before i get distortion is 2.4 volts to 9.5 volts notice more so out put of ic 1 ca3140.
Attachments
syncmix11 (2).gif
syncmix11 (2).gif (10.04 KiB) Viewed 12394 times
P1060692-crop (1).JPG
P1060692-crop (1).JPG (261.3 KiB) Viewed 12394 times
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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Re: Mirror Camera project

Postby gary » Sat Jul 19, 2014 5:26 pm

aaaaah! That's better Harry (although really you should have a diagram showing us how you are tying the top circuit into the mixer - a couple of strokes of a pencil would do it). I presume the sync pulse from the is being fed into the top of the voltage divider at the base of Q1?

In any case you can't have blown up Q1 otherwise you would be generating no syncs at all (I assume it IS still producing syncs?)

Q1 is acting as a switch for the strobe input of IC2 effectively tying it to ground - when this happens the output pin 6 swings to the voltage at pin 4 (which is tied to ground.

SO, the fact that your sync pulses are so deep must be that black clamp level (top of R2) is NOT .8v (please check with a volt meter) OR the gain of IC2 is too high (set by R4 - please check it's value).

Harry, I should have asked this before but I have assumed that when you record your tests that the output of mixer is being fed directly into your sound card? That is, there isn't another gain stage between the mixer and the sound card?

Anyway if you could check those 2 values (black clamp - .8V, and R4 we might get somewhere.

I have no explanation of why you are getting distortion when you supply rail is 12V - then again you haven't stated what kind of distortion it is.
gary
 

Re: Mirror Camera project

Postby Harry Dalek » Sat Jul 19, 2014 6:35 pm

gary wrote:aaaaah! That's better Harry (although really you should have a diagram showing us how you are tying the top circuit into the mixer - a couple of strokes of a pencil would do it). I presume the sync pulse from the is being fed into the top of the voltage divider at the base of Q1?



Hi Gary

i will get to that....... reason i didn't is its a work in progress and i didn't want to mislead any one ,having said that and now finding i have over looked things in this circuit rightly you have pointed out ,i will do a better schematic with what i left out .

In any case you can't have blown up Q1 otherwise you would be generating no syncs at all (I assume it IS still producing syncs?)


The problem is at the moment the line sync pulse from pin 7 adding it to Q1 sync mixer with out over riding the video ...just looking into this again if a cap or a resistor or both might be a better way to connect the two circuits and as you said i also have an amplitude problem of the sync pulse might be again the 12 volt supply dropping that to the 4528 monostable should shrink the pulse it works from 3 to 18 volts ,another thing i didn't take into account.

Q1 is acting as a switch for the strobe input of IC2 effectively tying it to ground - when this happens the output pin 6 swings to the voltage at pin 4 (which is tied to ground.

SO, the fact that your sync pulses are so deep must be that black clamp level (top of R2) is NOT .8v (please check with a volt meter) OR the gain of IC2 is too high (set by R4 - please check it's value).



I did check that it wasn't .8 of a volt a bit lower than that .7 but its distorted audio out working the circuit at 5 volts this reading is .3 and no distortion.
I checked the valves of R1 and 2 in case they are off but they are ok.


Harry, I should have asked this before but I have assumed that when you record your tests that the output of mixer is being fed directly into your sound card? That is, there isn't another gain stage between the mixer and the sound card?



No from mixer output right to lap top no amp or any thing.

Anyway if you could check those 2 values (black clamp - .8V, and R4 we might get somewhere.


R4 is 10k as i tested on 2 different supply voltages to the circuit i think i need less gain but i didn't try to increase the valve of R10 yet .

I have no explanation of why you are getting distortion when you supply rail is 12V - then again you haven't stated what kind of distortion it is.
[/quote]

I can do a recording feeding some low NBTV sound to it and the difference of a 5 volt supply to a 12volt .

i will record a test and up load
Last edited by Harry Dalek on Thu Nov 10, 2016 7:49 pm, edited 1 time in total.
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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Re: Mirror Camera project

Postby gary » Sat Jul 19, 2014 6:49 pm

The problem is at the moment the line sync pulse from pin 7 adding it to Q1 sync mixer with out over riding the video ...just looking into this again if a cap or a resistor or both might be a better way to connect the two circuits and as you said i also have an amplitude problem of the sync pulse might be again the 12 volt supply dropping that to the 4528 monostable should shrink the pulse it works from 3 to 18 volts ,another thing i didn't take into account.


Harry it should just go into the top of divider that's already in the circuit )between the pd1 and R6. (It's all on the same 12V power supply right?). The level of the input is not that important unless it burns Q1 out as Q! is only acting as a switch that is, on or off.

Harry first test - tie your video input to ground (VR1 full down will do that so it's easy).

Record a few seconds of that and post please.

Note there should be NO ac content at all at "black level clamp" just .8V (approx).
gary
 

Re: Mirror Camera project

Postby Harry Dalek » Sat Jul 19, 2014 7:09 pm

Gary you can test these 2 the 12 volt supply one is dreadful.

There seems to be a bandwidth problem as well i never tried to record it before and play it back ...live its ok on the 5volt test got nothing on play back .

May be i need to do a sweep test. or might have had the levels down much on record
Attachments
12voltvideosyncmixertest.wav
distortion on a 12 volt supply
(2.38 MiB) Downloaded 548 times
5volt supply video syn mixer test-old1.wav
(2.7 MiB) Downloaded 530 times
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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Re: Mirror Camera project

Postby Harry Dalek » Sat Jul 19, 2014 7:27 pm

gary wrote:Harry it should just go into the top of divider that's already in the circuit )between the pd1 and R6. (It's all on the same 12V power supply right?). The level of the input is not that important unless it burns Q1 out as Q! is only acting as a switch that is, on or off.


Oh but would i use instead of the photo diode or should i just use circuit as it is in the schematic and fed my pulse to the led do an optic connection ,i suppose that might work mmmmmmm.

Harry first test - tie your video input to ground (VR1 full down will do that so it's easy).


So it would record nothing black screen.

Record a few seconds of that and post please.

Note there should be NO ac content at all at "black level clamp" just .8V (approx).
[/quote]

I will try :)
Last edited by Harry Dalek on Thu Nov 10, 2016 7:53 pm, edited 2 times in total.
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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Re: Mirror Camera project

Postby gary » Sat Jul 19, 2014 7:38 pm

Harry you just use the voltage divider part - it will look like the video input but it will be the voltage divider R6 and R7 instead of RV1 - you do understand that RV1 is just a "variable" voltage divider right? Just think of R6 and R7 being the same as RV1 with the slider fixed in one place.

Yes I know you have done it before but I want to make sure that the input is grounded - once I have confirmed that and had a look at the wave file then I can tell you what to test next.
gary
 

Re: Mirror Camera project

Postby Harry Dalek » Sat Jul 19, 2014 8:02 pm

gary wrote:Harry you just use the voltage divider part - it will look like the video input but it will be the voltage divider R6 and R7 instead of RV1 - you do understand that RV1 is just a "variable" voltage divider right? Just think of R6 and R7 being the same as RV1 with the slider fixed in one place.


Sorry Gary I am confused we are talking the sync input here yes .

I think you are saying just use R6 and R7 and feed the sync in Base of Q1 as is yes ?

Yes I know you have done it before but I want to make sure that the input is grounded - once I have confirmed that and had a look at the wave file then I can tell you what to test next.


So i would expect a no signal record ? a black screen if i tried to view yes ?

The first wav is 5 volt vr1 on 0
12 volt is the same bit of hum and circuit noise present
Attachments
v1 on 0.wav
(886.92 KiB) Downloaded 522 times
v1 on 0 12volt supply.wav
(501.26 KiB) Downloaded 509 times
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.
User avatar
Harry Dalek
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Re: Mirror Camera project

Postby gary » Sat Jul 19, 2014 8:42 pm

ermmm... not quite sure what you mean by that Harry but yes I want sync added in via the voltage divider r6/r7 by applying the monostable output in via top of R6 BUT I also want you to turn RV1 completely to the left so the video input is pure black = 0v - then the cct should raise that to .8 V and the sync pulse will be added to that - i.e. it *should* go from +.8V to zero. All that means is we only have sync coming in - but it is ABSOLUTELY IMPERATIVE that RV1 be turned all the way down so we don't have any floating induced voltages floating about.

Please remember why I am asking this - I only want ONE thing coming in at a time otherwise there is just no way to sort out the mess.
gary
 

Re: Mirror Camera project

Postby gary » Sat Jul 19, 2014 8:43 pm

yes black screen is what we want
gary
 

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