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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 15th Apr 2023, 5:03 pm   #1
FRANK.C
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Default Hedghog L Standards Converter

The FPGA's needed to build the previous Hedghog's have become very difficult if not impossible to get. The Hedghog L is in response to that.

The Hedghog L uses a iCE40HX1K FPGA and a PIC microcontroller. The FPGA is very small compared to the Cyclone FPGA's used in earlier Hedghog's. So much so that before I tried I did not know if even the most basic converter would fit in it. It was chosen mainly because at the time of starting this project there was a good number of them in stock.

As much as possible of the workings of the converter was farmed out to the PIC so as to leave as much room as possible free in the FPGA. Even after doing that the converter had to be pruned back hard in order to get it to fit.

It uses a 2 line interpolater as it was all that would fit.
It has an option of equalising pulses and also can do aspect ratio of 4:3 in to 4:3 or 5:4 out.
Doing 16:9 in to 4:3 or 5:4 out would need little more space but would not fit.
One way of obtaining more functionality is to use a multiple boot system to programme the FPGA. With a number of programme images stored in flash memory. Each image can have a totally different function to each other. Depending on which function is required the appropriate image can be loaded into the FPGA.

To this end I have used 4 programme images.
1 is a 405 line converter with 4:3 input 4:3/5:4 output.
2 is a 405 line converter with 16:9 input 4:3/5:4 output.
3 is a 405 line test card.
4 is a 819 line converter4:3 input 4:3 output.

It also has a programmable multi standard modulator

The PIC now does the programming of the modulators and the video decoder. It also provides the 4 MHz clock for the modulators, drives the LCD and reads the encoders.

It's performance isn't up to that of previous Hedghog's but that said it still does a reasonably good conversion.

Details can be found here

Frank
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Old 15th Apr 2023, 9:08 pm   #2
slidertogrid
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Default Re: Hedghog L Standards Converter

Are they available ready built? I have the previous model but would like another.
Rich
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Old 15th Apr 2023, 9:14 pm   #3
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Default Re: Hedghog L Standards Converter

Hi Rich
I don't supply them. But forum member Freya does built them.

Frank
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Old 16th Apr 2023, 10:58 am   #4
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Default Re: Hedghog L Standards Converter

Hello Frank,

Thank you for your update.

Does program image 2 - '405 line converter with 16:9 input 4:3/5:4 output', do a 4:3/5:4 centre grab or does it 'squash' the entire 16:9 image into 4:3:5:4?

Cheers.
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Old 16th Apr 2023, 11:47 am   #5
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Default Re: Hedghog L Standards Converter

Hi
This Hedghog operates the same as others with this feature.

If you were to use it in 4:3 to 4:3 mode and the input was 16:9. The entire 16:9 would get squashed to 4:3.
When used in 16:9 to 4:3 the appropriate amount gets cropped off each side to leave the centre so it will fit in 4:3 with the correct aspect ratio.

I hope that answers your question OK.

Frank
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Old 16th Apr 2023, 1:32 pm   #6
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Default Re: Hedghog L Standards Converter

Thank you Frank, yes it does. Kind regards,

Andy
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Old 16th Apr 2023, 4:34 pm   #7
murphyv310
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Default Re: Hedghog L Standards Converter

Hi.
Great work as usual Frank.
I wonder if they will be priced cheaper? I suppose that's a question for Stephen!
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Old 16th Apr 2023, 6:57 pm   #8
FRANK.C
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Default Re: Hedghog L Standards Converter

Hi Trevor
Stephen would be the best person to ask about that.
But I couldn't see them being any cheaper. Components have gone up in price.
It is a while since I ordered PCB's but back then they were around 30 euro.
The last ones I got cost 42 euro. This mostly down to some country's outside the EU are now collecting VAT and duty for the EU at the point of sale.
That may not be the case in the UK.

Frank
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Old 25th Apr 2023, 5:41 pm   #9
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Default Re: Hedghog L Standards Converter

As Frank suggested I contacted Stephen for a ready built converter. It arrived today and I am very pleased with it. Easy to use, comprehensive instructions are supplied. I connected it to my faithful Dynatron and it works very well!
I have taken a couple of pictures. This is a slightly early birthday present to myself it will be my bench converter and means I won't have to keep unplugging the other Hedghog each time I want 405 on the bench.
Thanks Frank thanks Stephen ! Much appreciated!
Rich.
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