I haven’t done more tests with the mods, but as stated in my previous post, main issue is the logic being powered by +5V on Cadet Sync Gen and the 27MHz VCXO being +3.3V only. So maybe using a logic level converter to go from +5V at the output of the PLL to +3.3V to feed the lag/lead filter just before the VC input of the VCXO could work, there will surely be a bit of propagation delay, though might be negligible enough.
Else, most logic chips have a Vcc/2 input threshold (here 2.5V) , so in most cases, a +5V powered logic chip can accept a +3.3V signal at its input fine. The only critical part here is the VCXO VC, that needs to be +3.3V, since it expects a linearly changing signal, so it requires to be in the right range for the genlock feature to work as it should.
As was mentioned previously, it would be cool if the HC4046 oscillator could be used directly, without the need for a crystal at all. But as someone noted, the stability might be an issue. Anyone tried it yet?
Is anyone still thinking about taking this further? I have only 1 cadet sync generator but 2 RGB encoders. The plan always had been to have a second sync generator but they sold out before I got around to it
i’m also pinging this to find out if this was ever resolved – i am building a small system, and i would really need two CI’s to get it to work… seems the situation is somewhat hopeless at the moment
edit.; alternatively, are there any modules that could replace 2 Cadet I’s? i would appreciate all input
edit 2: or, perhaps, someone here has the specs of the VCXO in question? i can find some 13.5 mhz ones available… maybe there is some replacement option on the market still?
I don’t have an answer to your questions, but why do you need two C1s (especially for a small system)? Typically you only need one sync generator, and then you distribute that sync from there.
oh, you’re right, i needed to build two because we were thinking of assembling similar systems with a friend. for one system, yes, i intended to use just the one
Cool. Just making sure you weren’t thinking you could use them for something you can’t.
(BTW, if you don’t get an answer here, you can try on the lzx discord. It seems to be more active than this forum these days. Which is too bad because I prefer forums over discords.)
I just completed a Cadet Sync Generator this past month. It was tricky, but it works well. Here’s some preliminary documentation that might help. It’s still a work in progress. Hope it helps …
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