Re: TRIO CO-1303D
Posted: Fri Oct 06, 2017 6:33 pm
Robonz wrote:Hi Harry
I do not fully understand what you are are doing but I can say if your DAC output is a bit delayed compared to the rest of the system then the 100uF output capacitor is likely adding some delay to your signal. It will only be a tiny delay though. To prove it you could add another 100uf capacitor on top of the 100uf and if the delay remains the same it is not the problem.
Any solution welcome Keith i more than likely have not explained what i am up to at this point reason i keep testing the slides at 32 64 line before moving on to higher line rates .
Problems ......to make the line and frame sawtooth for the scope raster that the pmt flying spot picks up Steve came up up with this digital solution using first a master clock running at 3.2768MHZ ......first this was a 4046 R/C oscillator and drift off that frequency was not much but it does not take much at the other end on the line frequency to go right out of sync ..i got a bit fed up with that and found there was a crystal at that frequency so i made a 4060 crystal oscillator and used that till now... i have a capacitor trimmer on it which i can adjust it a bit ...so i have adjusted the clock to one of the out puts of the 4040 line ic and pin 12 gives 400hz and i adjusted it to that ..recording that and playing back to Garys Doms software the sync is locking no drift but the out put of the DAC it drifts slight very slow picture roll so this ic must be causing a delay .....your solution might fix that or getting my frequency meter on the output of the DAC and seeing if i can adjust that clock to it .
The next problem is i making the video signal to record the video i am taking and i needed the line 400hz to insert via a monostable to the video sync mixer ...pin 12 of the line 4040 ic was a solution but because of i think the above first problem the sync bar is half way in the frame ..when i use as now the the out put of the DAC to do the same thing as in these videos i made today it is fine apart from the drift again ..So i am thinking the DAC is delaying things a slight amount which is understandable but i was not expecting that .
These videos are a bit better trying to find 35mm slides with large images ...the wav files shows the drifting but are clear need to adjust the aspect ratio by the looks of it ,i will post these two up and put some more later ...