zx-sizif-512
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RGBS Jitters every few seconds.
Hi,
Once again thanks for this great project/
RGBS video jitters every few secs, it happens on both Sizif that I built. The is sent from the Sizif video out to a GBS=Control upscaler, image is nice, sharp and clean except for the jitters. Video is in PAL mode and GBS-Control detects it correctly as PAL. Jitter also doesn't happen with my other game consoles. Here is a clip of the jitter - https://youtu.be/2h-cfVabX18
Thanks in advance. Terence
Hello I've never dealt with GBS. I suppose there is some incompatibility with Pentagon video signal timings, which is going beyond PAL specifications. Can you check in 48K and 128K modes?
Actually, The Pentagon timing is the only 1 that works, the others won't even lock.
Ouch, that's unexpected. 48K timings are best in terms of compatibility with TVs. Are you using latest firmware? How GBS is connected to Sizif? Is your TV/Monitor supports 50Hz? Can you check frequency on 74HCU clock output? There is should be 28 MHz exactly.
sadly, the clock is not 28Mhz exactly. it jitters at 27.78, 28.04, 28.09.
It think I my 74HCU04 might be the problem, the China seller might have give me 74HC04. Let me double check. Thanks.
is the clock out from 74HCU04N supposed to be a Square wave? mine is a sine wave. Ordering some 74HCU04 to try.
This may be caused by oscilloscope bandwidth limitation.
I have a RIGOL DS1052E. will it measure 28Mhz properly?
No. It's have 50MHz bandwidth. To get accurate square waveform at least 10x (280MHz) bandwidth required.