Hedghog PSC programmable standards converter

[Jac]

It is the same with the video output of Philips CD-i players.
Fine with TV, but not working with standards converters.
Only the Dinosaur standards converter can handle that signal well! (Pineapple not tried.)

Jac

[FRANK.C]

Hi Courtney
The Hedghog's uses a TVP5150 video decoder. They require a 625 line composite signal. If for some reason the signal is non standard it may not work. It would be good to have a look at the signal with a scope.

Frank

[FRANK.C]

The Hedghog's uses a TVP5150 video decoder. They require a 625 line composite signal. If for some reason the signal is non standard it may not work. It would be good to have a look at the signal with a scope.
The Aurora also uses the TVP5150.


Something like the signal not being interlaced would cause the the converter not to work properly. As it needs to be able to tell which is the odd and even field in order to do the conversion.


Frank

[Jac]

The Domino sc uses a TDA8708 ADC and an LM1881 sync separator and also cannot handle the apparently non-standard video signal of the CD-i players.
Aurora uses also a TVP5150 video decoder, and has the same behaviour.

Jac

[marceljack]

The composite output of all home computers was non interlaced in order to avoid a line flicker which would be unaccepatble with a fixed picture displaying text.

The effective scanning was 312 line progressive with 50 Hz frame rate.
The useful line number was 288 but the graphic resolution was generally limited to 640 x 240 or 320 x 240 in order to be able to see the full picture despite the overscan of CRT TVs.

If the standard converter expects only interlaced signals, it will not synchronise properly.
TVs are very tolerant to non standard signals and accept 625i/25 or 312p/50 indifferently.

[FRANK.C]

Thanks for that explanation marceljack. That pretty much explains why any of the Hedghog's wont work from a composite signal from a home computer.


I have used a modern laptop as a signal source. By using the HDMI output from the laptop and a HDMI to composite converter.

Frank

[McMurdo]

the blackstar orion pattern generator also outputs non-interlaced signals as I found out when it sent my aurora (temporarily) loopy

[Semir_DE]

Hi Frank,

What a great project! I will PM you for a couple of PCBs if available

Is there any chance to make something like this with SDI input? That would allow HD signals to be used as an input. On Aliexpress you can get a very inexpensive HDMI to SDI converter. like this one:

https://www.aliexpress.com/item/4000...archweb201603_

I had recently ordered one and it seems to also work with my Blu-Ray player

So if you had SDI input capability the use of HDMI sources would be possible. Just a thought...

If you need an SDI source for testing e.g. a professional camera I might be able to help

[FRANK.C]

Hi Semir
SDI is something that could be looked at. A new project perhaps

But I have some unfinished business with this one first.
I want to give it a test card and also the ability to convert from 525 lines. It is almost there but I had to shelve it for a while.
The changes will be made in a firmware update.


Frank

[Freya]

Hi Semir,

I have about 30 boards, if thats any use.

Stephen

[FRANK.C]

I have updated the firmware on the Hedghog PSC webpage.
The FPGA and PIC firmware has changed and also the menu description has been updated to take account of the changes.


The update adds some new features.
It can now convert from 525 lines as well as 625 lines. The input standard is automatically detected.
I have also added some test patterns. Test card, Grey scale, Cross hatch, cruciform, Black screen and White screen.
The test patterns are inserted before the converter so are available on all output standards.

Frank

[Freya]

Well done, for all you hard work and effort.

[Jac]

Excellent results again Frank!

Thanks for all the work you've put into the Hedghogs!

Jac