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Television Standards Converters, Modulators etc Standards converters, modulators anything else for providing signals to vintage televisions.

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Old 29th Aug 2012, 6:59 pm   #181
pitbuell94
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Default Re: 819 line standards convertor.

Hi CMJONES01,

Thank you for the support.

I'm just coming back from hollydays.

I 'll make tests asap and I give you the result.

Fred.
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Old 1st Sep 2012, 9:46 am   #182
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Default Re: 819 line standards convertor.

Hi,

After ckecking, the sync line signal is good.

It seems to be that there is problem with the data stored in the FIFO.

In normal way, For each line I have 510 pixels. => 510 * 80 ns = 40.8 µs (visible video in 819 line standart) but I think I sample for example "X" sample in entrance ( 625 lines) and I have for example for output signal "X" + or - Delat value.

Because of this, the next line on the screen never start at dot "0" but at Dot "0" + Delta depending of the line number shows in the screen .

I need to go back to sckool to calculate the start and the stop value of the sample function.

In parallel, I have a lot of problem with my hardware design.

Because there is some problem with the 5V, the less signifiants bits are not taken in account => bit 0, 1 and sometime 2...

I rebuild soon a new PCB with separate power supply voltage for each part( Digital, analog and final amplifier stage).

Fred C( Pitbuell94).
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Old 4th Sep 2012, 4:06 pm   #183
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Default Re: 819 line standards convertor.

Hi,

For those we want to convert and store some PIC in memory, I have this small soft.

Use it directly with DOS.

Minimun version is 1.6 for JAVA.

The name is rawgsconverter.

This soft take any pic and make a conversion to B&W file.

This file is like a bin file or hexa file.

You can resize the final B&W pic.

for e.g => resize=1000x768 => the output PIC is 1000 dot per 768 lines.


Here below, the synthax to use it.

rawgsconverter.exe inputfile=test2.jpg outputfile=pouet.raw resize=1000x768


Lecture de l'image......[OK]
Redimensionnage......[OK]
Convertion en niveaux de gris......[OK]
Convertion en byteArray......[OK]
Sauvegarde......[OK]
[Termine]

After all is ok, you'll find a file with matching gray level you can flash into your ROM.

Fred C.(Pitbuell94).
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Old 4th Sep 2012, 4:07 pm   #184
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Default Re: 819 line standards convertor.

Hi Again,

If you have any question concerning the previous post you can contact me.

Fred C( Pitbuell94).
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Old 14th Sep 2012, 7:00 am   #185
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Default Re: 819 line standards convertor.

Hi,

Some small goods news from last week.

Now, the picture don't move anymore from right to left but I have always a normal picture and in the same time, an other one cut in two pieces by the middle of the screen.

I send PIC soon.

Fred.
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Old 14th Sep 2012, 1:18 pm   #186
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Default Re: 819 line standards convertor.

Hi again,

As I promised, the picture.

It seems to be this is the night of the Walking Dead...

I try to do my best, the impossible things are on the way, for miracle, please give me a delay. .

Fred.
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Old 24th Oct 2012, 3:41 pm   #187
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Default Re: 819 line standards convertor.

Hi everyone,

Here I am.

The converteur runs good?

The electronic design was OK from the beginning.

The defective spare part was the LM1881.

I replace it by the EL 4583 who gives real synchro pulse.

In the same way, I rebuild the complet PCB.

There is a PSU for each function => 4 * LM 7805

2 * 5 V for the TDA 8708
1 * 5V for the TDA 8702
1 * 5V for the EL 4583.


The main problem were coming from the interpolator and the fact that I need to go back to school to make calculation and soustraction.

I output more pixel than I take from the input signal

Some PIC of the system.

Fred. (PITBUELL94).
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Old 25th Oct 2012, 1:02 pm   #188
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Default Re: 819 line standards convertor.

Magnifique! Well done for sticking with it, should spur me on I've had my FPGA development kit for a few years now and hardly done anything with it!
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Old 25th Oct 2012, 2:31 pm   #189
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Default Re: 819 line standards convertor.

Hi dominicbeesley,

What kind of FPGA kit did you have?

Mine is a FPGA kit from Digilent.

It's an NEXYS2 with a SPARTAN 3E and 500K gates.

For the converter, I thing you can use less than 500K gates.

In fact, you need at least in the FPGA to have around 8 KBytes of RAM.

=> 4 KBytes per FIFO => there is 2 FIFO working in paralel.

Then you add TDA8708, TDA 8702 and a EL4583( synchro extractor).

Don't forget to put to all signal a resistor between 100 ohms to 470 ohms to avaoid frying your FPGA ( Only 3v Tolerant...).

If you want my final code, I can supply it to you.

The same for the schematic.

Fred C.( Pitbuell94).
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Old 25th Oct 2012, 3:13 pm   #190
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Default Re: 819 line standards convertor.

Hi dominicbeesley,

In case your FPGA kit have not enough RAM, you can use external IC RAM like 4164 ( RAM about 8Kbytes) and just add the missing code to drive it.

You'll need at least to have 28 pin for the IO signal.

The total code is around of 30 k0.

DON'T FORGET TO ADD IN SERIE RESISTOR TO PROTECT the IN Pins.

My design run with a clock of 50 MHz.

It'll be better to work with a clock of 100MHZ.

Let me know what kind of kit you hve.

Fred C.
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