Getting the bug.
Posted: Tue Oct 24, 2017 9:35 pm
Hi.
After the success with my modified Bush TV22 and able to resolve obsolete electronic standards from 120/24p to 240/25p I thought id have a go trying to resolve mechanical standards on the scope.
I'd already built a small board comprising a single transistor for video inversion and of course more drive, a sync seperator using a 1881 chip and a sawtooth generator for field scan using a 555 timer chip. This was a total success with excellent results from 819 lines down to the German 180 line system.
50/25p50/25p96/25p
So yesterday i thought I'd have a go using some of the Mechanical standards generated by my 2004 Aurora Multistandard converter. I fed the input with a 625 line test card "F", The generator produces a sine wave from one audio channel to sync up or drive a motor for the mechanical standards but the sine wave is of course related to the video signal so can be utilised for sync. Even with just the sine wave the scope will lock perfectly and oddly enough in most cases the 1881 chip produces some weak pulses for the 555 timer to lock onto, My time base will run down to just a few hertz96/25p so all frame rates are accommodated.
Here are a few samples i took yesterday.
Sorry something has gone amiss with the pictures and the comments.
Anyway I have the bug biting at me now so i'm now considering building a small monitor, I've a fair selection of old small Green screen tubes.
After the success with my modified Bush TV22 and able to resolve obsolete electronic standards from 120/24p to 240/25p I thought id have a go trying to resolve mechanical standards on the scope.
I'd already built a small board comprising a single transistor for video inversion and of course more drive, a sync seperator using a 1881 chip and a sawtooth generator for field scan using a 555 timer chip. This was a total success with excellent results from 819 lines down to the German 180 line system.
50/25p50/25p96/25p
So yesterday i thought I'd have a go using some of the Mechanical standards generated by my 2004 Aurora Multistandard converter. I fed the input with a 625 line test card "F", The generator produces a sine wave from one audio channel to sync up or drive a motor for the mechanical standards but the sine wave is of course related to the video signal so can be utilised for sync. Even with just the sine wave the scope will lock perfectly and oddly enough in most cases the 1881 chip produces some weak pulses for the 555 timer to lock onto, My time base will run down to just a few hertz96/25p so all frame rates are accommodated.
Here are a few samples i took yesterday.
Sorry something has gone amiss with the pictures and the comments.
Anyway I have the bug biting at me now so i'm now considering building a small monitor, I've a fair selection of old small Green screen tubes.