Handbook Sync Circuit

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Re: Handbook Sync Circuit

Postby FlyMario » Tue Aug 07, 2018 9:56 am

So, I modified the circuit and put a 150k Resistor on R1 (didn't have 180k) and a 1k to ground (R2). I am triggering on anything hitting around 0 volts. That is not very nice. I think R1 will have to get a Variable Resistor instead of a static resistor. Not sure about putting a Pot on a voltage divider circuit but oh well here we go. Probably a 470k pot going to pin 5 and then ground going into the 1k resistor(R2) to ground.

I feel I am very close to getting my trigger point correct.

Its just I think my trigger point is actually hitting above 0 volts not just in the negative area. Doesn't seem very logical thought. My scope seems pretty determined that it is.

Feel like I am chasing my own tail on this. LOL
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Re: Handbook Sync Circuit

Postby Harry Dalek » Tue Aug 07, 2018 4:12 pm

FlyMario wrote:Damn Harry. According to Texas Instruments, my LM358 should be a replacement for the AN1358.


Perhaps i have not tried that to see i do recall trying what i had on had and each gave a better worse result the An1358 worked the best .

Did you drop in your An1358 into the circuit (hand drawn) in place of the MC1458 or where there modifications? That sync pulse is perfect.


it's been a few years since i made that but i found a board i think i used with the AN1358 //i have it some where(EDIT i just found it) but any case it looks like i changed the 180k to a 106k the 1k resistor connected to it is the same as in the club circuit looks like no other changes ...
On the 5 volts thing yes i used 5 volts here reason i would think it must of been voltage sensitive ...i do recall being in your shoes and trying different part values and as i said opamps and seeing what effect it had on the results ...i was impressed with the An1358 for the sync pulse i don't recall if it was any better or worse for the video part of it ,i drew the schematic messy as it is and not corrected on the part values by the looks of it .

Next and more importantly, is your real last name Dalek or is it in appreciation for the robots in Dr. Who?

[/quote]

No its not my name i am a Harry but not a Dalek . just one of those silly names we all come up with from the start of the Internet bit like the old CB call sign i suppose
Yes i do like them and Drwho Classic more so ~! and they are not robots they have living creatures inside them :wink:
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Look i will give the AN1358 ic a test again see if the board is still ok and feed a video into it in fact i am close to needing sync pulse's for my project any case and it will be interesting to see if it can work 3 times fast 1.2khz and 3.6khz never know .Also need to correct that schematic mess!
EDiT i will post up the results i just did the sync detection on 400 hz it works great just as before !
Last edited by Harry Dalek on Tue Aug 07, 2018 10:03 pm, edited 3 times in total.
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Re: Handbook Sync Circuit

Postby Robonz » Tue Aug 07, 2018 5:09 pm

Hey FlyMario

I think the ADC on a Arduino would keep up, so long as you don't write verbose code. I think you only need around 11Khz to get an okay picture on 32 lines @ 12.5fps. I think a lot of Arduino's can do around 40Khz so 20khz should be pretty easy which is plenty. You will still need an op amp to get the voltage to fit the ADC window nicely. e.g. 0 to 5 or 0 to 3.3v

With all this op amp talk etc. The "narrow band" barely challenges even the cheapest op amp, so I really don't think it matters. The best thing to do is use a common pin out on a DIP chip. This means you can substitute anytime you like with a "plug in another one" hehe

Keep up the good work. I really want to see a picture from your machine!

If you need a difffuser then send me dimensions and a shipping address and I will ship you some samples for free.

My spam proof email is here https://edns.co.nz/contact/

Cheers
Keith
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Re: Handbook Sync Circuit

Postby Harry Dalek » Tue Aug 07, 2018 7:57 pm

Happy to report the AN1358 works as before ... Oh and i am not sure what video wav you are using, Steve Anderson made this for me testing my CRT Monitor the 3bp1 Anderson should be fine for a mechanical monitor as well its a clean correct NBTV video grey bars ...also remember to adjust your audio levels play the wav video to your circuit to low it will not work to high it will not work ...has to be just right like goldilocks :lol:
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Heres the circuit with a TL072 again works fine i don't think i had this ic when i did my original testing you should have one of these handy or easy to get .

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Next tried the Mc1458P as you see the pulse is not as good as the other 2 .
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I also tried the NE5532 and 4558 but both no goers at all with the circuit as is .

Doing the experiment on the 3 opamps that work i have to say the pulse looks cleanest with the TL072 ,the circuit is on 5 volts did not use the 3rd opamp for video as interested here on the sync detection.
I know i shorted the 33k 10nf base of the bc548 i have not tested this since i made this i think only reason for increased signal level to the transistor so greater light levels out of the luxeon ..but again i think you are more interested in the sync part which i am very happy with ....i have corrected the schematic it should of cause work as is if you want to make the minor changes 1 resistor and an opamp .
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Last edited by Harry Dalek on Tue Aug 07, 2018 9:56 pm, edited 9 times in total.
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Re: Handbook Sync Circuit

Postby Robonz » Tue Aug 07, 2018 8:15 pm

Hi Harry

All of those op amps should work fine based on the specs The issue I see is most of them have a minimum working voltage of 10 volts. To do these circuits at 5 volts the right op amp must be chosen that can work on 5 volts.

The AN1358 is versatile as it runs from 3 to 30v which makes it workable for 5v. When doing any circuit the power supply must be in spec to get a desired result. While I love the TLO72 and have used them and the TLO74. They do specify that you must use at least 10v to run them in spec.

The AN1358 is good advice and any other op amp that works in the 5v region.

Cheers
Keith
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Re: Handbook Sync Circuit

Postby Harry Dalek » Tue Aug 07, 2018 8:45 pm

Robonz wrote:Hi Harry

All of those op amps should work fine based on the specs The issue I see is most of them have a minimum working voltage of 10 volts. To do these circuits at 5 volts the right op amp must be chosen that can work on 5 volts.

The AN1358 is versatile as it runs from 3 to 30v which makes it workable for 5v. When doing any circuit the power supply must be in spec to get a desired result. While I love the TLO72 and have used them and the TLO74. They do specify that you must use at least 10v to run them in spec.

The AN1358 is good advice and any other op amp that works in the 5v region.

Cheers
Keith


Hi Rob ...really i think these opamps should be on a dual supply ..but i know from experimenting you can not tell the difference some times on a single supply .
Also i should of used my variable supply to test also i know i would of used 5 volts for a reason ..
Due to the differences in side the things which i have no idea (magic?) :D they do give different results if you look at the slope in the AN1358 to the dead on perfect TlO72 result its really how fussy or clean you want your pulse all 3 will work ...its funny how in the real world these things can operate i have used the Tl072 in head amps pretty sure they are happier on 5 volts .
I will be doing some sync Tests of my own on the FSC monitor and i will test varying the voltage just to see on the resulting waveform ..
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Re: Handbook Sync Circuit

Postby FlyMario » Thu Aug 09, 2018 1:15 pm

Tonight I rebuilt my circuit using the CA3140 OP-AMP and I am getting a nice signal.

I don't really want to credit the OP-AMP for it more ... my own stupidity.

I realized while connecting this one op that I had been taking the 1k resistor into a 100k pot without connecting them via the legs but instead to the wiper which would have made the voltage divider really not one. It would make them in parallel instead of series. Blarb.

I think my 100k pot should probably be one of these long screw ones with more throw than this dial one. And probably be more like 200k. The signal is nice but It occasionally gets off. I could probably decide to ignore the bad pulses because the timing between them would be way off. However, I would like to get them near perfect.

So yeah, I think I am close with the sync part. I need to get on this so I can watch some TV. :)
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Re: Handbook Sync Circuit

Postby Steve Anderson » Thu Aug 09, 2018 7:00 pm

For those that haven't seen it I did a sync-pulse-extraction, frame-pulse-extraction and video clamping circuit some eight years ago...I'm not sure if it appeared in the newsletter or not. Looking back over it it potentially could do with some simplification without compromising performance. But for what it's worth here is the 2010 version...

It uses an 8-pin PIC micro to do the bulk of the work, the rest is fairly conventional analogue 'glue'. Circuits, text and 'scope screen-scrapes attached.

Now the problem for most with all software-based items of this nature is programming the chips. I'm happy to do that for anyone interested, the chips and postage should be under US$2.00 - so forget about it - unless thousands respond - I think unlikely! If anyone is interested let me know via this thread or a PM...

The Word file explains how it works and the limitations of it...

I need to find the prototype - I'm sure it's here somewhere...

Steve A.
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Re: Handbook Sync Circuit

Postby FlyMario » Thu Aug 09, 2018 11:27 pm

So here is the circuit to obtain the Sync. It matches the Club Circuit with exception of having a 200K Linear Pot to trim the trigger point and using the CA3140 OP-AMP which is a single version of the version used in the original circuit.

I am happy that I switched to the Linear Pot as it really helped me tweak the pulses to where I was happy. What design program do you folks use? I found this Digikey online one pretty fun but don't like when wires have to hop over other wires. It creates a headache. I would prefer the hopping(?) symbol than trying to show a break. I remember in electronic school (NAVY) in the 80's that a ball is actually proper for showing a connection but seems that is a dead standard maybe.


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Re: Handbook Sync Circuit

Postby Robonz » Thu Aug 09, 2018 11:38 pm

Hi Fly

Its great to see you making progress. Just a couple of notes.

1) There is no decoupling capacitor across the supply of the chip/s (in your diagram). You can end up with random sync pulses without it. Each op amp should have something like a 0.1uf or 0.01uf capacitor directly across the chip.

2) The input signal should be in a coaxial cable. You can end up with random sync pulses with out it.

Also your 5V rail should have at least 47uf capacitor across it for noise suppression.

Good luck
Keith
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Re: Handbook Sync Circuit

Postby FlyMario » Thu Aug 09, 2018 11:47 pm

Robonz wrote:Hi Fly

Its great to see you making progress. Just a couple of notes.

1) There is no decoupling capacitor across the supply of the chip/s (in your diagram). You can end up with random sync pulses without it. Each op amp should have something like a 0.1uf or 0.01uf capacitor directly across the chip.

2) The input signal should be in a coaxial cable. You can end up with random sync pulses with out it.

Also your 5V rail should have at least 47uf capacitor across it for noise suppression.

Good luck
Keith


Ahh great info! Thanks!
FlyMario
 

Re: Handbook Sync Circuit

Postby Harry Dalek » Fri Aug 10, 2018 1:01 am

FlyMario wrote:So here is the circuit to obtain the Sync. It matches the Club Circuit with exception of having a 200K Linear Pot to trim the trigger point and using the CA3140 OP-AMP which is a single version of the version used in the original circuit.

I am happy that I switched to the Linear Pot as it really helped me tweak the pulses to where I was happy.


There are many ways to do the same thing and if it works go for it ,i used a pot at the start to tune it into then went with a fixed resistor

]What design program do you folks use? I found this Digikey online one pretty fun but don't like when wires have to hop over other wires. It creates a headache. I would prefer the hopping(?) symbol than trying to show a break. I remember in electronic school (NAVY) in the 80's that a ball is actually proper for showing a connection but seems that is a dead standard maybe.


We were all taking about this a while back with Steve on the forum hoping or the brake cross over no one likes i think .Also taking about the best schematic program on line ,the one i liked the most was just a demo and they wanted 9 bucks a month after that so went looking again i sort of like circuit lab but again it not free either after sucking you into it .https://www.circuitlab.com/editor/#
it will show the hope on crossed wires .
i have just been trying copying and paste schematic images seeing if that's away to go ,its ok but a touch messy on the wiring ...on mine there is a point when you have to draw something memory on so much wiring can only go so far and nice to know how to remake some thing that works .
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: Handbook Sync Circuit

Postby FlyMario » Fri Aug 10, 2018 1:20 am

I am playing with DesignSpark PCB at the moment. I saw online that it would draw Hops. But sometimes it feels like these get overly complex. I guess it is about making the component to where you like it and then saving them to a user file. One day I would like to take my little Mill ( https://www.amazon.com/gp/product/B01GF ... UTF8&psc=1 ) to make a PCB. And maybe send out to have one made. Just to say I have done it.

Right now I am prototyping on one of these ( https://www.amazon.com/gp/product/B0040 ... UTF8&psc=1 ) Yes it is way wasted space but whatever. It will do.

Wow looks like I am being paid by Amazon.

I bought some of these the other day ( https://www.jameco.com/z/MCP41010-I-P-M ... 41744.html ) they look fun. Probably won't use on this project.

Do you test those big Volume control type of rotary pots by measuring the leg to the middle to find out if they are good? I tried to use one for the video signal and it seemed no good. I had to cross the video input directly into the coupling cap before I got a signal to go through the op amps.
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Re: Handbook Sync Circuit

Postby gary » Fri Aug 10, 2018 10:12 am

FlyMario wrote:Wow looks like I am being paid by Amazon.


Yes, I hate it when people put links to Amazon ;-), It's like taking a young child into a sweet/lolly/candy shop and telling them that they can only look.

(For all intents and purposes we don't have access to Amazon here in Australia - I am, of course, green with envy).
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Re: Handbook Sync Circuit

Postby smeezekitty » Fri Aug 10, 2018 11:15 am

FlyMario wrote:Do you test those big Volume control type of rotary pots by measuring the leg to the middle to find out if they are good? I tried to use one for the video signal and it seemed no good. I had to cross the video input directly into the coupling cap before I got a signal to go through the op amps.

I would test from outside to outside first to make sure it reads the rated resistance. And then test from the wiper to one of the outside terminals. Slowly turn it and make the resistance varies smoothly from 0 to the rated resistance
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